tag:theconversation.com,2011:/us/topics/lifespan-8497/articlesLifespan – The Conversation2024-01-22T13:27:25Ztag:theconversation.com,2011:article/2019272024-01-22T13:27:25Z2024-01-22T13:27:25ZBreaking down fat byproducts could lead to healthier aging − researchers identify a key enzyme that does just that<figure><img src="https://images.theconversation.com/files/569661/original/file-20240116-25-w3uhfy.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A buildup of fat byproducts like glycerol may contribute to accelerated aging.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/oily-water-royalty-free-image/492968264">MagicColors/iStock via Getty Images Plus</a></span></figcaption></figure><p>The journey of aging brings with it an unavoidable reality for many: an increased accumulation of body fat. Though much of society seems mostly focused on the aesthetics of being overweight, doctors look past any cosmetic concerns to focus on the health implications of fat byproducts in the body.</p>
<p><a href="https://www.britannica.com/science/fatty-acid">Fatty acids</a> are one of the molecular building blocks that make up fats. Though essential for various bodily functions, excessive amounts of fatty acids in the body <a href="https://doi.org/10.1111/acel.13048">can be harmful</a>, shortening a person’s <a href="https://theconversation.com/are-you-a-rapid-ager-biological-age-is-a-better-health-indicator-than-the-number-of-years-youve-lived-but-its-tricky-to-measure-198849">health span and life span</a> by increasing their risk of chronic disease, disrupting metabolic processes and promoting inflammation. </p>
<p>Fatty acids are <a href="https://medlineplus.gov/lab-tests/triglycerides-test/">routinely checked</a> during medical examinations, such as blood tests measuring your lipid profile. But clinicians and researchers often overlook the other key component of fat despite its potentially harmful effects: <a href="https://doi.org/10.1016/j.cmet.2009.10.003">glycerol</a>, a compound that links fatty acids to make a fat molecule. </p>
<p>Both of these fat byproducts disrupt cellular and organ function, mirroring the effects of aging. In fact, researchers are increasingly seeing obesity as a <a href="https://doi.org/10.3389%2Ffendo.2019.00266">catalyst for accelerated aging</a>.</p>
<p>The role that fats play in aging is one of the focuses of my work as a <a href="https://scholar.google.com/citations?user=O3qOkKsAAAAJ&hl=en">genomicist and biochemist</a>. My <a href="https://www.agingobesitylab.org">research team</a> and I wondered whether reducing harmful fat byproducts might help slow the aging process and consequently stave off common diseases. </p>
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<figcaption><span class="caption">Fats perform essential functions in your cells, but not all of them are good for you.</span></figcaption>
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<h2>Breaking down fat byproducts</h2>
<p>In studying ways to extend the life span and improving the health at late age of lab animals, my colleagues and I saw a <a href="https://doi.org/10.1016/j.cub.2023.01.059">consistent pattern</a>: All the anti-aging interventions we tested led to reduced glycerol levels.</p>
<p>For instance, when placed on a calorie-restricted diet, the nematode <em>Caenorhabditis elegans</em> <a href="https://doi.org/10.1073/pnas.95.22.13091">lives about 40% longer</a>. We found that the glycerol levels in the body of these long-lived worms were lower than in shorter-lived worms that were not food restricted. Calorie restriction also <a href="https://doi.org/10.1016/j.cub.2023.01.059">heightened the activity of an enzyme</a> responsible for breaking down glycerol, ADH-1, in their intestine and muscles.</p>
<p>We saw similar <a href="https://doi.org/10.1016/j.cub.2023.01.059">high ADH-1 activity levels in people</a> undergoing dietary restriction or treated with an anti-aging drug called rapamycin. This finding suggests there may be a common mechanism underlying healthy aging across species, with ADH-1 at its core.</p>
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<a href="https://images.theconversation.com/files/569663/original/file-20240116-20-gctpab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Figure showing the chemical structure of glycerol, a fatty acid, and a triglycerol" src="https://images.theconversation.com/files/569663/original/file-20240116-20-gctpab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/569663/original/file-20240116-20-gctpab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=792&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569663/original/file-20240116-20-gctpab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=792&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569663/original/file-20240116-20-gctpab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=792&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569663/original/file-20240116-20-gctpab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=995&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569663/original/file-20240116-20-gctpab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=995&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569663/original/file-20240116-20-gctpab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=995&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Triacylglycerols, also known as triglycerides, are composed of a glycerol linked to three fatty acids.</span>
<span class="attribution"><a class="source" href="https://bio.libretexts.org/Bookshelves/Microbiology/Microbiology_(Boundless)/02%3A_Chemistry/2.05%3A_Organic_Compounds/2.5.02%3A_Lipid_Molecules">Lumen Learning (formerly Boundless) via LibreTexts</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We hypothesized that elevated ADH-1 activity promotes health in old age by decreasing harmful levels of glycerol. Supporting this hypothesis were <a href="https://doi.org/10.1016/j.cub.2023.01.059">two critical observations</a>. First, we found that adding glycerol to the diet of worms <a href="https://doi.org/10.1016/j.cmet.2009.10.003">shortened their life span by 30%</a>. By contrast, animals genetically modified to boost levels of the glycerol-busting enzyme ADH-1 had low glycerol levels and remained lean and healthy with longer lives, even on unrestricted diets. </p>
<p>The simple molecular structure and wealth of research on ADH-1 make it an attractive target for developing drugs that boost its activity. My lab’s long-term goal is to explore how compounds that activate ADH-1 affect the health and longevity of both mice and people.</p>
<h2>A long-lived society</h2>
<p>Anti-aging research generates both excitement and debate. On the one hand, the benefits of <a href="https://theconversation.com/aging-is-complicated-a-biologist-explains-why-no-two-people-or-cells-age-the-same-way-and-what-this-means-for-anti-aging-interventions-202096">healthy aging</a> are clear. On the other hand, extending life span through healthier aging will likely introduce new societal challenges. </p>
<p>If life spans extending to 120 years become the norm, <a href="https://doi.org/10.1016/S2666-7568(21)00250-6">social structures</a>, including retirement ages and economic models, will need to evolve to accommodate an aging population. Legal and social frameworks regarding the elderly and family care may need revision. The <a href="https://www.washingtonpost.com/parenting/2023/03/22/caregivers-sandwich-generation/">sandwich generation</a>, those with children and living parents and grandparents, might find themselves caring for even more generations simultaneously. Longer lives will require society to rethink and reshape how we integrate and support an increasingly older population in our communities.</p>
<p>Whether through ADH-1 or dietary adjustments, the quest for the solution to healthy aging is not just a medical journey but a societal one.</p><img src="https://counter.theconversation.com/content/201927/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eyleen Jorgelina O'Rourke does not receive funding from any organization that would benefit from this article. </span></em></p>Although you get your fatty acid levels routinely checked at the doctor’s, rarely do clinicians and researchers consider the effects of their potentially harmful byproducts.Eyleen Jorgelina O'Rourke, Associate Professor of Biology and Cell Biology, University of VirginiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2113182023-08-28T12:02:28Z2023-08-28T12:02:28ZThere’s no age limit for politicians − as people live longer, should that change?<figure><img src="https://images.theconversation.com/files/544368/original/file-20230823-19-gm3p1u.jpeg?ixlib=rb-1.1.0&rect=6%2C9%2C2150%2C1425&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mitch McConnell, Diane Feinstein and Joe Biden are all over 80 years old, joining a number of politicians who are staying in office well past their 70s. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com">Anna Moneymaker/Chip Somodevilla/Samuel Corum/Getty Images </a></span></figcaption></figure><p>President Joe Biden was “<a href="https://twitter.com/WHCommsDir/status/1664347179282997258">fine</a>,” according to White House Communications Director Ben LaBolt, after tripping over a sandbag at a U.S. Air Force graduation ceremony on June 1, 2023.</p>
<p>But his fall was caught on live camera – and people on <a href="https://twitter.com/search?q=biden%20trips%20at%20US%20Air%20Force%20Academy">social media</a> speculated about what was behind it. </p>
<p>Biden, approaching his 81st birthday in November 2023, is the <a href="https://thehill.com/changing-america/enrichment/arts-culture/3744771-here-are-the-oldest-us-presidents-to-ever-hold-office/">oldest serving U.S. president</a>. He shares the distinction of old age with a growing number of politicians, including 81-year-old U.S. Senator Mitch McConnell.</p>
<p>On Aug. 30, 2023 81-year-old Sen. Mitch McConnell <a href="https://www.washingtonpost.com/politics/2023/08/30/mcconnell-freeze-speaking/">froze after a reporter asked him</a> about his re-election plans. He remained silent for more than 20 seconds, his gaze distant, including after a political aide asked him if he heard the question.</p>
<p>“We’re going to need a minute,” the aide said, and a few moments later ushered the senator away from the lectern. </p>
<p>This followed a <a href="https://newrepublic.com/post/174621/hell-just-happened-mitch-mcconnell-press-conference">similar incident with McConnell</a> in July 2023. </p>
<p>Some people – from fellow Democrats to <a href="https://www.nytimes.com/2023/05/05/opinion/dianne-feinstein-senate.html">The New York Times editorial board</a> – have questioned whether McConnell and other colleagues, including <a href="https://www.feinstein.senate.gov/public/index.cfm/biography">90-year-old Dianne Feinstein</a>, can fulfill the duties of their jobs. With Feinstein, there have been incidents in which she stumbled over words. She began reading prepared remarks during a Senate appropriations hearing vote on July 27, 2023, until her democratic colleague, <a href="https://www.cbc.ca/player/play/2250078787777">Sen. Patty Murray, whispered to her, “Just say aye.”</a>’</p>
<p>Such incidents prompt the question: Can politicians be too old to serve in office? Should society make retiring at a certain age mandatory for elected officials who run the country – like presidents and senators? </p>
<p><a href="https://depts.washington.edu/bhdept/nancy-s-jecker-phd-sheher">I am a philosopher and bioethicist</a> who studies <a href="https://global.oup.com/academic/product/ending-midlife-bias-9780190949075?cc=us&lang=en&#:%7E:text=Jecker%20coins%20the%20term%2C%20midlife,raises%20fundamental%20problems%20of%20fairness">ethics related to individual and societal aging</a>, and these questions are at the forefront of what I think about. Whatever view one takes on the ethics of age limits for politicians, voting remains the primary way to put one’s views into practice. </p>
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<a href="https://images.theconversation.com/files/543790/original/file-20230821-17-76jzq1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People in formal clothing gather around Mitch McConnell, who is at a lectern" src="https://images.theconversation.com/files/543790/original/file-20230821-17-76jzq1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543790/original/file-20230821-17-76jzq1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543790/original/file-20230821-17-76jzq1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543790/original/file-20230821-17-76jzq1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543790/original/file-20230821-17-76jzq1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543790/original/file-20230821-17-76jzq1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543790/original/file-20230821-17-76jzq1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Sen. John Barrasso helps Senate Minority Leader Mitch McConnell after he froze at the microphone on July 26, 2023.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sen-john-barrasso-reaches-out-to-help-senate-minority-news-photo/1556768368?adppopup=true">Drew Angerer/Getty Images</a></span>
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<h2>Minimum age requirements</h2>
<p>Requirements for U.S. presidential candidates haven’t changed since 1789, when <a href="https://guides.loc.gov/sb.php?subject_id=162830">the Constitution</a> was written.</p>
<p>Today, the life span for the average American is <a href="https://www.macrotrends.net/countries/USA/united-states/life-expectancy">79 years</a>. But it tends to be much higher for people like politicians, who are relatively wealthy and <a href="https://www.cdc.gov/about/sdoh/index.html">receive good health care</a>. </p>
<p>In the U.S., a person needs to be 35 years old or older <a href="https://www.loc.gov/classroom-materials/elections/presidential-election-process/requirements-for-the-president-of-the-united-states/">in order to be president</a>. A person must be at least 25 years old in order to serve in the House of Representatives, while the minimum age rises slightly to 30 years old for serving in the Senate. </p>
<h2>A question of maximum age limits</h2>
<p>The U.S. <a href="https://www.eeoc.gov/statutes/age-discrimination-employment-act-1967">banned age discrimination in workplaces</a> in 1967. </p>
<p>Should politicians who lead the country be an exception to this law? </p>
<p>A 2022 YouGov poll reported that <a href="https://today.yougov.com/topics/politics/articles-reports/2022/01/19/elected-officials-maximum-age-limit-poll">58% of Americans want</a> a maximum age for politicians. Those who support age limits usually say that politicians holding office should be no more than 70 years old. That would make <a href="https://www.pewresearch.org/short-reads/2023/01/30/house-gets-younger-senate-gets-older-a-look-at-the-age-and-generation-of-lawmakers-in-the-118th-congress">71% of current U.S. senators ineligible</a> to hold office. It is unclear how age limits like that could be implemented. </p>
<p>Increasingly, people everywhere will be forced to confront questions about whether a person can be too old to hold public office. <a href="https://www.census.gov/library/stories/2023/05/aging-united-states-population-fewer-children-in-2020.html">People are living longer lives</a> in the U.S., but the same is true <a href="https://desapublications.un.org/publications/world-social-report-2023-leaving-no-one-behind-ageing-world">across the world</a>. </p>
<h2>Ethical arguments for age limits</h2>
<p>Considering age limits for high-ranking politicians poses certain ethical questions that do not have a clear answer.</p>
<p>Staying in office despite health problems can threaten public safety. An American president holds immense power – including the ability to launch nuclear weapons. Members of Congress are responsible for making laws, declaring war and controlling taxes and spending.</p>
<p>Defenders of mandatory retirement say <a href="https://pubmed.ncbi.nlm.nih.gov/9158965/#:%7E:text=Four%20important%20characteristics%20of%20the,an%20aversion%20to%20inequality%3B%20and">older people have had their turn</a>.</p>
<p>Yet, if giving everyone a fair turn is the goal, why not cap the number of years worked? Like age limits, however, capping years <a href="https://doi.org/10.1111/josp.12471">would disproportionately affect older workers</a> – and some say that’s unjustly discriminatory.</p>
<p>Even without age cutoffs, age could still be a way to flag other relevant factors, like health. </p>
<p><a href="https://doi.org/10.1371/journal.pone.0229160">As people age, they face heightened risk of chronic disease</a> and of having multiple chronic conditions. Chronic health problems can interfere with daily functioning and put older politicians at higher risk of performing poorly on the job –- for example, falling.</p>
<p>Testing health – or, even better, job performance – is another option. Testing workers of all ages at regular intervals avoids ageist stereotypes. </p>
<p>Biden undergoes an annual health screening and has been deemed “<a href="https://www.whitehouse.gov/wp-content/uploads/2023/02/Health-Summary-2.16.pdf">fit for duty</a>.” Should Feinstein and McConnell be held to the same standard? That raises the thorny question, what if physicians disagree about a politician’s health and ability to remain in office? </p>
<h2>Ethical arguments against age limits</h2>
<p>Health checks differ from compulsory retirement. </p>
<p>In rich Western countries, people do not retire because they can no longer work –retirement is not correlated with an <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4214452/">actual reduction in physical or intellectual capabilities</a>. </p>
<p>Instead, <a href="https://DOI.org/10.1136/jech-2015-207097">people’s health</a> tends to decline <a href="https://doi.org/10.1371/journal.pone.0220857">after retiring</a>.</p>
<p><a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/josp.12471">Those who oppose compulsory retirement</a>, <a href="https://www.seattletimes.com/opinion/the-corrosive-power-of-ageism/">myself included</a>, say that mandating retirement generates ageism, or negative stereotypes based on age.</p>
<p>Experts have shown that older people are diverse, and they separate biological aging – like physical wear and tear on the body – from chronological aging.</p>
<p>In addition to stereotyping older people, forced retirement <a href="https://doi.org/10.1111/josp.12471">violates principles of equality</a>. People equally able to perform a job deserve equal chances to continue to work, independent of factors unrelated to job performance, such as age, race or gender identity. </p>
<p>Supporters of age-based retirement, meanwhile, say that this policy <a href="https://books.google.com/books/about/Am_I_My_Parents_Keeper.html?id=hGpHAAAAMAAJ">treats people equally over time</a>, since all young people eventually become old. Yet others disagree, insisting that <a href="https://doi.org/10.1086/233897">the point of equality is creating a community of equals</a>, and discriminating against older adults falls short.</p>
<h2>The people decide</h2>
<p>People supporting a maximum age limit for the president and members of Congress have launched online <a href="https://www.change.org/p/president-of-the-united-states-maximum-age-limit-for-congress-and-presidency">signature campaigns on Change.org</a>. But these efforts would require a constitutional amendment and have not gained major traction. </p>
<p>Two Republican senators also <a href="https://www.cruz.senate.gov/newsroom/press-releases/sen-cruz-introduces-constitutional-amendment-to-impose-term-limits-for-congress">introduced an amendment</a> to the U.S. Constitution in 2023 that would allow senators to serve only two six-year terms and Congress members to serve three two-year terms. Congress has voted down <a href="https://crsreports.congress.gov/product/pdf/IF/IF12343">previous proposals to set term limits</a>. </p>
<p>At the state level, <a href="https://www.ncsl.org/about-state-legislatures/the-term-limited-states">16 states limit terms</a> for legislators – but not necessarily because of age concerns. Direct age limits are under consideration in South Dakota, which will <a href="https://apnews.com/article/north-dakota-congressional-candidates-age-limit-e8c321aa3b180f51607899876750f066">vote in 2024</a> on a ballot measure to amend the state’s constitution and establish an upper age limit of 80 years for congressional candidates.</p>
<p>Since the government sets age minimums for Congress and the presidency, should there be maximum limits, too? This question remains open. In a democracy, we the people decide by voting.</p>
<p><em>Correction: We have updated this story to eliminate a reference to the average life expectancy in the U.S. in the late 1700s.</em></p><img src="https://counter.theconversation.com/content/211318/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nancy S. Jecker does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>While there are minimum age requirements for people who want to hold political office in the US, there are no limits on when someone must retire.Nancy S. Jecker, Professor of Bioethics and Humanities, School of Medicine, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2068522023-06-25T13:35:00Z2023-06-25T13:35:00ZFinding joy at age 100: Talking to centenarians about living their best life at any age<figure><img src="https://images.theconversation.com/files/530460/original/file-20230606-27-okg1ov.png?ixlib=rb-1.1.0&rect=143%2C0%2C1657%2C1003&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Centenarian Clementina Ripplinger with researcher Heather Nelson. Researchers spoke to very elderly people about what brings them joy and how they plan for the future.</span> <span class="attribution"><span class="source">(Shane Luhning)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Aging is seen as a period of loss, and there are unhelpful <a href="https://www.nia.nih.gov/health/10-myths-about-aging">myths about older adults</a>. Myths lead to treatable conditions being considered normal parts of aging, including cognitive decline, dementia, depression and loneliness. Some even consider exercise dangerous in older adults.</p>
<p>At the same time, mainstream media promotes the message that <a href="https://doi.org/10.4236/jss.2017.58015">being young is central to a person’s value</a>. These ideas lead to ageism and older adults being seen as lesser.</p>
<p>After spending time with six female centenarians in assisted living facilities, our research team — which included four nursing researchers and a documentary filmmaker — learned there is plenty still worth living for. </p>
<p>Centenarians are a small but growing segment of the population with <a href="https://www150.statcan.gc.ca/n1/en/daily-quotidien/220928/dq220928c-eng.pdf?st=LrkfjZE_">13,844 centenarians in Canada</a>, and our findings debunk myths about the experience of aging.</p>
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<figcaption><span class="caption">Trailer for documentary film about talking to centenarians.</span></figcaption>
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<p>We asked the centenarians questions about what brings them joy and how they plan for the future because we wanted to learn how the very elderly plan for and find ways to live their best lives. The results of this study were <a href="https://vimeo.com/showcase/looking-forward-at-100">turned into a 32-minute documentary</a> that captures participants’ long and interesting lives and offers insight into continued meaning experienced by centenarians in their daily lives. Three of the centenarians died shortly after the interviews took place.</p>
<h2>Long and interesting lives</h2>
<p>The participants were born between the years 1919 and 1922. They were children during the Great Depression and young adults during the Second World War. </p>
<p>One of the women helped build bullet casings and worked on the <a href="https://www.britannica.com/technology/Lancaster-airplane">Lancaster bomber</a>. Another woman helped her husband protect the blueprints of the ill-fated <a href="https://www.thecanadianencyclopedia.ca/en/article/avro-arrow">Avro Arrow aircraft</a> when he brought them home from work. Two women lost their husbands when their children were small and had to go to work to support their families. They all experienced love and adventure. </p>
<p>Our team was fascinated by their stories and wanted to further explore what their lives look like today. </p>
<p>Betty, 101, saw happiness as a choice. “I don’t know what’s really to complain about. I went through life staying happy,” she said.</p>
<h2>Joy and challenges</h2>
<p>This study used a research method called <a href="https://www.scribd.com/doc/151684840/Braun-Clarke-2006-Using-Thematic-Analysis">thematic analysis</a> to find four themes: Finding Joy, Act your Age, Looking Forward and Putting Challenges into Perspective.</p>
<p>The centenarians found joy each day and enjoyed the little things such as activities, visits and treats. Betty enjoyed cheating at solitaire and Jean, 100, played the piano. Clementina, 101, had fun gambling and Joyce, 100, continued to write stories and watch her grandchildren in music concerts.</p>
<p>Family was central to their lives and they enjoyed spending time with their children, grandchildren and great-grandchildren. Two of the women stated that raising their children was the biggest accomplishment in their lives.</p>
<p>The centenarians also found great joy in reminiscing about their interesting lives. However, one of the challenges was that there was no one left alive who had the same shared experiences.</p>
<h2>Limitations</h2>
<p>The centenarians were constrained by the limitations of society, their bodies and their self-perceptions. “You have to act your age,” said Clementina. She physically described this phenomenon by clasping her hands together in her lap and sitting still. </p>
<p>Some participants found life to be boring at 100 compared to their lives as younger adults. They had limited opportunities to do what they would like. “We had homes,” said Joyce, 100, describing how they had known better lives, which made it hard to accept the constraints of their current existence. </p>
<p>In spite of these feelings, many of the participants continued to be busy and live life fully despite limitations. Jean, despite needing a wheelchair for mobility, continues to do people’s taxes for a volunteer organization, plays piano for church services and leads choirs within her facility. </p>
<p>“I am constantly rebelling against my situation physically,” she said.</p>
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<p>The other women in this study also continued to challenge norms of what their age and disabilities meant. Joyce writes and submits short stories for publication, and has a poem in the war archives in Ottawa.</p>
<p>Assisted living facilities often prioritize resident safety, but this can come at a cost to personal freedom. Some residents only leave their facility accompanied by a facility employee or a family member. Clementina rebelled against this restriction and at the age of 97, snuck out of her assisted living facility in a cab to go to the casino, pretending that she was going to meet her son.</p>
<p>All of the participants put their life challenges into perspective. They all had lost spouses, friends and some had lost their children. “I was broken,” Clementina said about losing her husband. </p>
<p>Christine, 102, was asked how she managed after losing her husband when her children were still small. “I am still here,” she said.</p>
<h2>The future</h2>
<p>Most of the centenarians had few plans for themselves for the future and were more interested in leading their day-to-day lives. Betty jokingly described the inevitability of her death and that she was “looking for the bucket.” Most described being prepared to die except for Jean, who laughed and said she didn’t have time to die. “I have too many plans.”</p>
<p>The centenarians looked to the future of their families and the larger community and entrusted the next generation to make good choices.</p>
<p>Participants in this study had long and interesting lives and continued to find meaning each day. This study supports the idea that older adults continue to lead engaging lives and that we need to support older adults to live their best lives at any age.</p>
<p><em>This article was also co-authored by journalist and filmmaker Kelly-Anne Riess and retired nursing instructor Susan Page.</em></p><img src="https://counter.theconversation.com/content/206852/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Heather Joyce Nelson receives funding from the Saskatchewan Health Research Foundation and the Social Sciences and Humanities Research Council.</span></em></p><p class="fine-print"><em><span>Beverlee Ziefflie receives funding from the Saskatchewan Health Research Foundation and the Social Sciences and Humanities Research Council. </span></em></p><p class="fine-print"><em><span>Paula Mayer receives funding from the Saskatchewan Health Research Foundation and the Social Sciences and Humanities Research Council. </span></em></p>What is life like at 100? Centenarians shared their joys and future hopes with a team of Saskatchewan researchers.Heather Joyce Nelson, Assistant Professor of Nursing, University of ReginaBeverlee Ziefflie, Instructor, Nursing, Saskatchewan PolytechnicPaula Mayer, Associate Research Scientist, Nursing, Saskatchewan PolytechnicLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2059802023-05-25T12:27:37Z2023-05-25T12:27:37ZAmericans are increasingly moving to red, Republican-leaning states – where life is cheaper, but people also die younger<figure><img src="https://images.theconversation.com/files/527818/original/file-20230523-15-2671gg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">While blue, Democratic states are becoming bluer, red, Republican-leaning states are becoming more conservative. </span> <span class="attribution"><a class="source" href="https://media.gettyimages.com/id/1332599651/photo/divided-american-flag-in-window.jpg?s=1024x1024&w=gi&k=20&c=YofHukGaSoRcgrB59fBzp47y8zYm91SW5xEaVntqcc4=">Matt Champlin</a></span></figcaption></figure><p>The United States is an <a href="https://www.pewtrusts.org/en/trust/archive/winter-2021/america-is-exceptional-in-its-political-divide">increasingly polarized country</a> when it comes to politics – but one thing that almost all people want is to live a <a href="https://www.washingtonpost.com/wellness/2023/01/25/longevity-centenarians-healthy-living/">long, healthy life</a>.</p>
<p>More and more Americans are moving from <a href="https://www.cbsnews.com/news/states-where-americans-are-moving-florida-texas-north-carolina-south-carolina/">Democratic-leaning blue states to Republican-voting red ones</a>, and one of the effects of this change is that they are relocating to places with lower life expectancy. </p>
<p>Idaho, Montana and Florida, <a href="https://wisevoter.com/state-rankings/red-and-blue-states/">all red states</a>, had the <a href="https://www.axios.com/2023/04/07/population-change-pandemic">greatest population growth</a> among U.S. states between 2020 and 2022. Meanwhile, New York and Illinois, both blue states, and Louisiana, a red state, suffered the biggest population losses. California, another blue state, has experienced significant <a href="https://www.nytimes.com/2023/05/03/us/california-population-decline.html">recent population loss</a> as well.</p>
<p>One key reason for this migration is the <a href="https://www.seattletimes.com/nation-world/californias-population-dropped-by-500000-in-two-years-as-exodus-continues/">high cost of living</a> in places like New York and California, compared with the lower cost of living in red states such as <a href="https://www.forbes.com/home-improvement/moving-services/cheapest-states-to-live-in/">Georgia or Indiana</a>. </p>
<p>I am a scholar who <a href="https://writing.ucsb.edu/people/robert-samuels">studies the intersection</a> between politics, media and psychology. I think it is important to note that another trend, though, is that people are largely migrating to places with <a href="https://www.prb.org/resources/liberal-u-s-state-policies-linked-to-longer-lives/">lower life expectancies</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/527820/original/file-20230523-23-1oyxlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An aerial view shows suburban houses, all similar with dark roofs and white exteriors." src="https://images.theconversation.com/files/527820/original/file-20230523-23-1oyxlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527820/original/file-20230523-23-1oyxlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527820/original/file-20230523-23-1oyxlm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527820/original/file-20230523-23-1oyxlm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527820/original/file-20230523-23-1oyxlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527820/original/file-20230523-23-1oyxlm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527820/original/file-20230523-23-1oyxlm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An aerial view of a new housing development in Houston, Texas, which has experienced significant population growth in recent years.</span>
<span class="attribution"><a class="source" href="https://media.gettyimages.com/id/534814446/photo/usa-texas-suburban-housing-developement.jpg?s=1024x1024&w=gi&k=20&c=-4LxrUj_mSjHO3p701SusJwwVyDMVRHBlcGYTrx8A7o=">Brooks Kraft LLC/Corbis via Getty Images</a></span>
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<h2>Understanding demographics</h2>
<p>There is a <a href="https://www.cdc.gov/nchs/pressroom/sosmap/life_expectancy/life_expectancy.htm">large difference in expected life spans</a> for people living in certain states, according to U.S. Centers for Disease Control and Prevention data.</p>
<p>For instance, people born in New York and California – two of the <a href="https://worldpopulationreview.com/state-rankings/richest-states-in-usa">richest states</a> in the country, which largely vote Democratic – have a <a href="https://www.cdc.gov/nchs/pressroom/sosmap/life_expectancy/life_expectancy.htm">life expectancy</a> of 77.7 and 79 years, respectively. But people in Mississippi and Louisiana – two of the <a href="https://worldpopulationreview.com/state-rankings/poorest-states">poorest states</a>, which tend to vote Republican – live, on average, until they are <a href="https://www.cdc.gov/nchs/pressroom/sosmap/life_expectancy/life_expectancy.htm">71.9 and 73.1 years old</a>.</p>
<p>People who live in Republican-leaning states tend to have <a href="https://www.moneygeek.com/living/states-most-reliant-federal-government/">less money</a>, <a href="https://www.scientificamerican.com/article/people-in-republican-counties-have-higher-death-rates-than-those-in-democratic-counties/">worse health conditions</a>, higher rates of <a href="https://www.forbes.com/sites/ariannajohnson/2023/04/28/red-states-have-higher-gun-death-rates-than-blue-states-heres-why/?sh=739569121f81">gun-related deaths</a> and <a href="https://worldpopulationreview.com/state-rankings/least-educated-states">lower levels of education</a> than people living in Democratic states.</p>
<p><a href="https://www.census.gov/newsroom/press-releases/2022/acs-5-year-estimates.html">On average, people in red states have higher rates of poverty</a> than residents of blue states.</p>
<p>Poverty is an indicator for life expectancies in the U.S. – the poorer someone is, the more likely to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7792745/">die younger</a>. </p>
<p>But there are likely other issues at play in people in red states’ having lower life spans.</p>
<h2>Health differences</h2>
<p>Research in 2020 showed that Americans in blue states tend to live longer than people in red states, <a href="https://www.globenewswire.com/news-release/2020/08/04/2072712/0/en/Researchers-say-where-you-live-could-add-years-to-your-life.html">primarily because of state policies</a> on everything from seat belt laws to abortion laws. That research also identified health policies as a major factor. </p>
<p>People in blue states also tend to have <a href="https://www.kff.org/other/state-indicator/total-population/?currentTimeframe=0&sortModel=%7B%22colId%22:%22Location%22,%22sort%22:%22asc%22%7D">higher rates of health insurance</a> than people in red states. </p>
<p>Moreover, when looking at the rates of people who are diagnosed with <a href="https://worldpopulationreview.com/state-rankings/cancer-rates-by-state">cancer in each state</a>, it is clear that people in red states are generally less healthy than people in blue ones. Red-state residents are also more likely to <a href="https://www.cdc.gov/dhdsp/maps/national_maps/hd_all.htm#:%7E:text=Heart%20Disease%20Death%20Rates%2C%20Total%20Population%20Ages%2035%2B&text=The%20map%20shows%20that%20concentrations,%2C%20Kentucky%2C%20Tennessee%20and%20Guam.">die from heart disease</a> than people in blue states.</p>
<p>But health rates vary greatly across racial and ethnic groups. Black and Hispanic people are far more likely than white and Asian people in the U.S. to not have access to <a href="https://www.kff.org/racial-equity-and-health-policy/report/key-data-on-health-and-health-care-by-race-and-ethnicity">quality affordable health care</a>, regardless of their state of residence.</p>
<p>And <a href="https://www.cdc.gov/vitalsigns/aahealth/index.html">Black people remain more likely</a> than white people to have high blood pressure and to die from heart disease, <a href="https://www.cdc.gov/healthequity/features/maternal-mortality/index.html">among other health conditions</a>.</p>
<h2>Lower education levels</h2>
<p>Another key factor in this life span trend is that people in red states have <a href="https://worldpopulationreview.com/state-rankings/educational-attainment-by-state">lower levels of education</a> than people in blue states.</p>
<p>This matters, since some recent research has shown that education levels are the best <a href="https://news.yale.edu/2020/02/20/want-live-longer-stay-school-study-suggests#:%7E:text=Each%20educational%20step%20obtained%20led,are%20powerful%2C%22%20Roy%20said">predictor of a person’s life span</a> for a variety of complex, interconnected reasons, including an increased likelihood that receiving a higher education will <a href="http://doi.org/10.1186/s41118-019-0055-0">lead to a boost in income</a>. </p>
<p>Experts also often consider race and ethnicity another <a href="https://www.kff.org/racial-equity-and-health-policy/issue-brief/what-is-driving-widening-racial-disparities-in-life-expectancy/:%7E:text=As%20of%202021,%20provisional%20data,Asian%20people%20at%2083.5%20years.">major factor</a>, in part because of <a href="https://www.brookings.edu/articles/unequal-opportunity-race-and-education/">structural inequalities</a> facing people of color that may place access to quality affordable education out of reach, for example. </p>
<p>Lack of education may be the most direct reason for <a href="https://www.routledge.com/Educating-Inequality-Beyond-the-Political-Myths-of-Higher-Education-and/Samuels/p/book/9781138084988">lower incomes and shorter lives</a> – but it is not clear if attaining a higher level of education makes people wealthier, or if people who are born into wealth receive more and better education.</p>
<h2>Are people moving to die young?</h2>
<p>There are other reasons that factor into the complex question of life expectancy, and discrepancies in longevity across states.</p>
<p>One reason identified by the Centers for Disease Control and Prevention, for example, is that there are more gun deaths – <a href="https://www.kff.org/other/issue-brief/do-states-with-easier-access-to-guns-have-more-suicide-deaths-by-firearm/">by homicide and suicide</a> – in red states <a href="https://www.cdc.gov/nchs/pressroom/sosmap/firearm_mortality/firearm.htm">than blue states</a>.</p>
<p>People are moving to different states in the U.S. for a variety of reasons – including, in some cases, political ideologies. While blue ZIP codes have been found to be getting bluer, <a href="https://www.npr.org/2022/02/18/1081295373/the-big-sort-americans-move-to-areas-political-alignment">red ones are becoming</a> even more red.</p>
<p>But it is important to keep in mind that data on life spans and health are simply averages, and so there can be a high variation within particular locations.</p>
<p>There are people in red and blue states who defy these statistics – many people living long lives in poor red states, and people dying younger in rich blue ones.</p>
<p>Still, the overall trends are clear. People living in blue states – by and large – tend to live longer, healthier and wealthier lives.</p><img src="https://counter.theconversation.com/content/205980/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Samuels does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Idaho, Montana and Florida had the highest population growth among US states between 2020 and 2022.Robert Samuels, Continuing Lecturer in Writing, University of California, Santa BarbaraLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2017742023-04-10T20:02:25Z2023-04-10T20:02:25ZThe rich are pouring millions into life extension research – but does it have any ethical value?<p>Sam Altman, the chief executive of OpenAI, <a href="https://www.technologyreview.com/2023/03/08/1069523/sam-altman-investment-180-million-retro-biosciences-longevity-death/">recently invested</a> US$180 million into Retro Biosciences – a company seeking to extend human lifespans by <a href="https://retro.bio/announcement/">ten healthy years</a>. </p>
<p>One way it plans to achieve this is by “rejuvenating” blood. This idea is based on studies that found old mice <a href="https://www.science.org/content/article/young-blood-renews-old-mice">showed signs of reversed ageing</a> when given the blood of young mice.</p>
<p>Altman isn’t the only Silicon Valley entrepreneur supporting life extension efforts. PayPal cofounder Peter Thiel, Amazon founder Jeff Bezos and Google cofounder Larry Page have <a href="https://www.theguardian.com/science/2022/feb/17/if-they-could-turn-back-time-how-tech-billionaires-are-trying-to-reverse-the-ageing-process">poured millions</a> into projects that could profoundly affect how we live our lives.</p>
<p>The first question raised is scientific: could these technologies work? On this front the jury is still out, and there are grounds for both <a href="https://newseu.cgtn.com/news/2021-01-14/How-close-are-we-to-radical-life-extension-and-is-it-a-good-idea--X03UFbnMWs/index.html">optimism</a> and scepticism.</p>
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<em>
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Read more:
<a href="https://theconversation.com/can-ageing-really-be-treated-or-cured-an-evolutionary-biologist-explains-143255">Can ageing really be 'treated' or 'cured'? An evolutionary biologist explains</a>
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<p>The second question is just as important: even if lifespan extension is feasible, would it be ethical? </p>
<p>We explain why some common ethical arguments against lifespan extension aren’t as solid as they might seem – and put forth another, somewhat overlooked explanation for why trying to live forever might not be worth it.</p>
<h2>Is it worth it if you still die anyway?</h2>
<p>One might argue lifespan extension merely pushes back the inevitable: that we will die. However, the problem with this view is that <em>any</em> life saved will only be saved temporarily. </p>
<p>A lifespan extension of ten years is akin to saving a drowning swimmer, only for them to die in a traffic accident ten years later. Although we might be sad about their eventual death, we’d still be glad we saved them.</p>
<p>The same is true of conventional medicine. If a doctor cures my pneumonia, I will eventually die of something else, but that doesn’t mean the doctor or I will regret my being saved.</p>
<p>It’s also worth taking a longer view of where lifespan extension research could lead us. In the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC423155/">most optimistic scenarios</a> put forth by experts, even modest short-term gains could help people add centuries to their life, since the benefits of each intervention could cascade. For example, each extra year of life would increase the likelihood of surviving until the next big breakthrough.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519492/original/file-20230405-26-uqi8e0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Small figures are lined up on a white surface, with a line counting up years of life in 10 year intervals." src="https://images.theconversation.com/files/519492/original/file-20230405-26-uqi8e0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519492/original/file-20230405-26-uqi8e0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=294&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519492/original/file-20230405-26-uqi8e0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=294&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519492/original/file-20230405-26-uqi8e0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=294&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519492/original/file-20230405-26-uqi8e0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=370&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519492/original/file-20230405-26-uqi8e0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=370&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519492/original/file-20230405-26-uqi8e0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=370&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Some philosophers have pointed out that immortality, while it may initially be desirable, would eventually lose its sheen.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Is it worth it if immortality could get boring?</h2>
<p><a href="https://www.sciencedirect.com/science/article/abs/pii/S0277953604004691">Many</a> <a href="https://www.sciencedirect.com/science/article/abs/pii/S0890406510000757">have argued</a> against lifespan extension on ethical grounds, saying they wouldn’t use these technologies. Why might somebody be opposed?</p>
<p>One worry is that a very long life might be undesirable. Philosopher <a href="https://www.cambridge.org/core/books/abs/problems-of-the-self/makropulos-case-reflections-on-the-tedium-of-immortality/9180185912980E017EE675254B2F4169">Bernard Williams</a> said life is made valuable through the satisfaction of what he calls “categorical desires”: desires that give us reason to want to live. </p>
<p>Williams expects these desires relate to major life projects, such as raising a child, or writing a novel. He worries that, given a long enough life, we will run out of such projects. If so, immortality would become tedious.</p>
<p>It’s unclear whether Williams is right. <a href="https://www.tandfonline.com/doi/abs/10.1080/09672559.2012.713383">Some philosophers</a> point out human memories are fallible, and certain desires could resurface as we forget earlier experiences. </p>
<p><a href="https://link.springer.com/article/10.1007/s10892-015-9203-8">Others</a> emphasise that our categorical desires evolve as our life experiences reshape our interests – and might continue to do so over the course of a very long life.</p>
<p>In either case, our categorical desires, and hence our reason for living, would not be exhausted over a very long life.</p>
<p>Even if immortality did get tedious, this wouldn’t count against modest lifespan extensions. Many would argue 80-something years isn’t enough time to explore one’s potential. Personally, we’d welcome another 20 or even 50 years to write a novel, or start a career as a DJ. </p>
<h2>Is it worth it if poor people miss out?</h2>
<p>Another worry regarding lifespan extension technologies is egalitarian. </p>
<p>These technologies will be expensive; it seems unjust for Silicon Valley billionaires to celebrate their 150th birthdays while the rest of us mostly die in our 70s and 80s.</p>
<p>This objection seems convincing. Most people welcome interventions that promote health <em>equality</em>, which is reflected in broader societal demands for universal healthcare. </p>
<p>But there’s important nuance to consider here. Consider that universal healthcare systems promote equality by <em>improving</em> the situation of those who aren’t well off. On the other hand, preventing the development of lifespan extension technologies will <em>worsen</em> the situation of those who are well off.</p>
<p>The ethical desirability of equality based on “<a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/1467-9329.00041">levelling down</a>” is unclear. The poorest Australians are <a href="https://theconversation.com/the-poorest-australians-are-twice-as-likely-to-die-before-age-75-as-the-richest-and-the-gap-is-widening-139201">twice as likely</a> to die before age 75 than the richest. Yet few people would argue we should stop developing technologies to improve the health of those aged over 75. </p>
<p>Moreover, the price of lifespan extension technologies would eventually likely come down.</p>
<h2>The real problem</h2>
<p>However, we think there’s one serious ethical objection that applies to extreme cases of life extension. If humans routinely lived <em>very</em> long lives, this could reduce how adaptable our populations are, and lead to social stagnation. </p>
<p>Even modest increases in life expectancy would radically increase population size. To avoid overpopulation, we’d need to <a href="https://theconversation.com/thinking-of-having-a-baby-as-the-planet-collapses-first-ask-yourself-5-big-ethical-questions-196388">reduce birth rates</a>, which would drastically slow generational turnover. </p>
<p>As one of us (Chris) has explored in previous <a href="https://academic.oup.com/jmp/article/40/6/696/2747126">research</a>, this could be incredibly harmful to societal progress, because it may:</p>
<ol>
<li>increase our vulnerability to extinction threats</li>
<li>jeopardise individual wellbeing, and</li>
<li>impede moral advancement.</li>
</ol>
<p>Many fields benefit from a regular influx of young minds coming in and building on the work of predecessors. </p>
<p>Even if the brains of older scientists remained sharp, their “confirmation bias” – a tendency to seek and interpret information in ways that confirm one’s prior beliefs – could slow the uptake of new scientific theories.</p>
<p>Moral beliefs are also prone to <a href="https://link.springer.com/article/10.1007/s10670-020-00252-1">confirmation bias</a>. In a world of extended lifespans, individuals whose moral views were set in their youth (perhaps more than 100 years ago) will remain in positions of power.</p>
<p>It seems likely our society’s moral code is <a href="https://link.springer.com/article/10.1007/s10677-015-9567-7">badly mistaken</a> in at least some respects. After all, we think past societies were catastrophically mistaken in theirs, such as when they endorsed slavery, or rendered homosexuality illegal.</p>
<p>Slowing generational turnover could delay the point at which we recognise and fix our own moral catastrophes, especially those we can’t yet see.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/life-extension-the-five-most-promising-methods-so-far-169881">Life extension: the five most promising methods – so far</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/201774/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julian Koplin receives funding from Ferring Pharmaceuticals.</span></em></p><p class="fine-print"><em><span>Christopher Gyngell via his affiliation with the Murdoch Children's Research Institute received funding from the Victorian State Government via the Operational Infrastructure Support Program. He also receives funding from the Medical Research Future Fund.</span></em></p>We all have a stake in life extension research, since we all age and are all slated to die. But one of the greatest risks it brings is the potential for social stagnation.Julian Koplin, Lecturer in Bioethics, Monash University & Honorary fellow, Melbourne Law School, Monash UniversityChristopher Gyngell, Research Fellow in Biomedical Ethics, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2007912023-04-10T12:04:23Z2023-04-10T12:04:23ZHow do trees die?<figure><img src="https://images.theconversation.com/files/517217/original/file-20230323-26-hsn4ob.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6001%2C4232&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Eventually weather, pests and disease will take their toll, but the story doesn't end there. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/dried-dead-tree-with-moss-trees-in-forest-royalty-free-image/1392619431">Emanuel David / 500px via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>How and why do trees die? – Anish K., age 11, Boston, Massachusetts</strong></p>
</blockquote>
<hr>
<p>Trees can die suddenly or quite slowly. </p>
<p>Fire, flood or wind can cause a quick death by severely damaging a tree’s ability to <a href="https://www.treehugger.com/process-of-using-water-by-trees-1343505">transport water and nutrients</a> up and down its trunk. </p>
<p>Sometimes a <a href="https://www.youtube.com/watch?v=vR30qlK0-Cw">serious insect attack</a> or disease can kill a tree. This kind of death usually takes from a few months to a couple of years. Again, a tree loses its ability to move water and nutrients, but does so in stages, more slowly. </p>
<p>A tree can also die of what you might call old age.</p>
<p>I am a <a href="https://scholar.google.com/citations?hl=en&user=g2KEhV4AAAAJ">scientist who studies trees</a> and the web of living things that surround them. The death of a tree is not exactly what it seems, because it directly leads to new life.</p>
<h2>Different trees, different life spans</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of an enormous old living tree." src="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=896&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=896&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=896&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1126&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1126&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1126&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An ancient bristlecone pine (<em>Pinus longaeva</em>) in Patriarch Grove in California’s White Mountains.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nturland/5817568646/in/photostream/">Nicholas Turland/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Trees can live an <a href="https://www.scientificamerican.com/article/trees-have-the-potential-to-live-indefinitely">incredibly long time</a>, <a href="https://onetreeplanted.org/blogs/stories/oldest-tallest-biggest-trees">depending on what kind they are</a>. Some <a href="https://www.nps.gov/grba/planyourvisit/identifying-bristlecone-pines.htm">bristlecone pines</a>, for instance, are among the oldest known trees and are more than 4,000 years old. Others, like lodgepoles or poplars, will have much shorter life spans, from 20 to 200 years. The biggest trees in your neighborhood or town are probably somewhere in that range. </p>
<p>You’ve probably noticed that different living things have different life spans – a hamster is generally not going to live as long as a cat, which isn’t going to live as long as a person. Trees are no different. Their life spans are determined by their DNA, which you can think of as the <a href="https://kids.britannica.com/kids/article/DNA/390730">operating system embedded in their genes</a>. Trees that are programmed to grow very quickly will be less strong – and shorter lived – <a href="https://extension.psu.edu/why-do-some-trees-live-longer-than-others">than ones that grow very slowly</a>. </p>
<p>But even a tough old tree will eventually die. The years and years of damage done by insects and microscopic critters, combined with abuse from the weather, will slowly end its life. The death process may start with a single branch but will eventually spread to the entire tree. It may take a while for an observer to realize a tree has finally died. </p>
<p>You might think of death as a passive process. But, in the case of trees, it’s surprisingly active. </p>
<h2>The underground network</h2>
<p>Roots do more than anchor a tree to the ground. They are the place where microscopic fungi attach and <a href="https://www.nytimes.com/interactive/2020/12/02/magazine/tree-communication-mycorrhiza.html">act like a second root system for a tree</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of thin spiderweb-looking filaments attached to roots." src="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some fungi look like fragile spiderwebs, but these tiny tubes act like superhighways underground.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Mycorhizes-01.jpg">André-Ph. D. Picard</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Fungi form long, superfine threads called hyphae. Fungal hyphae can <a href="https://www.scientificamerican.com/article/do-trees-support-each-other-through-a-network-of-fungi">reach much farther than a tree’s roots can</a>. They gather nutrients from the soil that a tree needs. In exchange, the tree repays fungi with <a href="https://www.youtube.com/watch?v=D1Ymc311XS8">sugars it makes out of sunlight</a> in a process known as <a href="https://www.britannica.com/science/photosynthesis">photosynthesis</a>. </p>
<p>You might have heard that fungi can also pass nutrients from one tree to another. This is a topic that scientists are still working out. Some trees are likely connected to other trees by a complex underground network of fungi, sometimes called the “<a href="https://www.newyorker.com/tech/annals-of-technology/the-secrets-of-the-wood-wide-web">wood wide web</a>.”</p>
<p>How the wood wide web functions in a forest is still not well understood, but scientists do know that the fungi forming these networks are important for keeping trees healthy.</p>
<h2>Afterlife of a tree</h2>
<p>Before it topples over, a dead tree can stand for many years, providing a safe home for bees, squirrels, owls and <a href="https://www.nwf.org/Garden-for-Wildlife/Cover/Trees-and-Snags">many more animals</a>. Once it falls and becomes a log, it can host other living things, like badgers, moles and reptiles. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A mossy trunk from a dead tree lies in the forest." src="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">One day the remains of this tree will be completely gone.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/october-2021-lower-saxony-uslar-a-mossy-trunk-from-a-dead-news-photo/1236121962">Swen Pförtner/picture alliance via Getty Images</a></span>
</figcaption>
</figure>
<p>Logs also host a different kind of fungi and bacteria, called decomposers. These <a href="https://vinsweb.org/the-fallen-log/">tiny organisms help break down big dead trees</a> to the point where you would never know they had existed. Depending on the conditions, this process can take from a <a href="https://vinsweb.org/the-fallen-log/">few years to a century or more</a>. As wood breaks down, its nutrients return to the soil and become available for other living things, including nearby trees and fungal networks.</p>
<p>A tree leaves a legacy. While alive, it provides shade, home for many animals and a lifeline to fungi and other trees. When it dies, it continues to play an important role. It gives a boost to new trees ready to take its place, shelter to a different set of animals and, eventually, nourishment for the next generation of living things.</p>
<p>It’s almost as if a tree never truly dies but just passes its life on to others.</p>
<hr>
<p><em>Editor’s note: This story has been updated to emphasize that much remains unknown about the relationship between trees and fungi.</em></p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/200791/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Camille Stevens-Rumann does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Even in death, a tree helps others live.Camille Stevens-Rumann, Assistant Professor of Forest & Rangeland Stewardship, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1907312023-01-13T13:32:03Z2023-01-13T13:32:03ZMarriage provides health benefits – and here’s why<figure><img src="https://images.theconversation.com/files/502228/original/file-20221220-20-6x1y81.jpg?ixlib=rb-1.1.0&rect=17%2C17%2C5674%2C3097&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In relationships, women tend to take the lead in promoting healthy behaviors.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/bride-and-groom-wedding-figurines-royalty-free-image/1133833685">Peter Dazeley/The Image Bank via Getty Images</a></span></figcaption></figure><p>The new year is traditionally a time when many people feel a renewed commitment to create healthy habits, such as <a href="https://theconversation.com/hate-exercise-small-increases-in-physical-activity-can-make-a-big-difference-127679">exercising regularly</a>, drinking more water or eating more healthfully.</p>
<p>It turns out that when it comes to health, married people have an edge, especially married men. But surely the act of walking down the aisle is not what provides this health advantage. </p>
<p>So what exactly is at play?</p>
<p>As a team, we study how relationships affect health. One of us is a <a href="https://hhs.purdue.edu/directory/elizabeth-libby-richards/">nursing professor</a> who studies how social support influences health behaviors. One is a <a href="https://hhs.purdue.edu/directory/rosie-shrout/">social health psychologist</a> who explores how stress affects couples’ relationships and health, and one is a <a href="https://hhs.purdue.edu/directory/melissa-franks/">social psychologist</a> who researches how relationships influence health behavior changes. Together, we examine how partners influence each other’s health, taking gender into account in this equation.</p>
<h2>Health benefits of marriage, for men and women</h2>
<p>It’s important to note that most marriage and health studies have been limited to married men and women. But <a href="https://theconversation.com/marriage-could-be-good-for-your-health-unless-youre-bisexual-121865">more recent studies</a> are examining these relationships in partners who have the same gender identity, the same biological sex and who are gender diverse.</p>
<p>One theory that seeks to explain the link between marriage and health is the <a href="https://doi.org/10.1016/j.euroecorev.2018.02.005">act of self-selection</a>. Simply put, people who are wealthier and healthier than average are more likely not only to get married but also to find a partner who is wealthier and healthier than average. Men and women with poorer health and wealth than average <a href="https://doi.org/10.1016/j.euroecorev.2018.02.005">are less likely</a> to marry at all.</p>
<p>While this may be part of the story, marriage also provides partners <a href="https://doi.org/10.1177/2047487316643441">with a sense of belonging</a>, more opportunities for social engagement and reduced feelings of loneliness. <a href="https://link.springer.com/referenceworkentry/10.1007/978-3-319-69892-2_646-2#Sec5">This social integration</a>, or the extent to which people participate in social relationships and activities, can greatly influence health – from <a href="https://doi.org/10.1177/0898264314551172">reducing the risk of hypertension</a> and <a href="https://doi.org/10.1161/CIRCRESAHA.116.309443">heart disease</a> to <a href="https://doi.org/10.1177/0898264311432310">lowering one’s risk of death</a> or <a href="https://doi.org/10.1001/jamapsychiatry.2015.1002">suicide</a>.</p>
<figure class="align-center ">
<img alt="Middle-aged woman with long gray hair riding a bicycle in foreground and middle-aged man riding a bike in background." src="https://images.theconversation.com/files/502004/original/file-20221219-13540-5oeq00.jpg?ixlib=rb-1.1.0&rect=60%2C0%2C6720%2C4466&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502004/original/file-20221219-13540-5oeq00.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502004/original/file-20221219-13540-5oeq00.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502004/original/file-20221219-13540-5oeq00.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502004/original/file-20221219-13540-5oeq00.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502004/original/file-20221219-13540-5oeq00.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502004/original/file-20221219-13540-5oeq00.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A spouse’s healthy habits, like eating well and exercising, tend to improve a partner’s health too.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/senior-mexican-couple-riding-bikes-royalty-free-image/1143944592">adamkaz/E+ via Getty Images</a></span>
</figcaption>
</figure>
<p>Another important connection between marriage and health involves the body’s inflammatory process. Research links <a href="https://doi.org/10.1016/j.neubiorev.2020.02.002">loneliness and lack of close relationships</a> with <a href="https://theconversation.com/what-is-inflammation-two-immunologists-explain-how-the-body-responds-to-everything-from-stings-to-vaccination-and-why-it-sometimes-goes-wrong-193503">inflammation</a>, or the body’s way of reacting to illness, injury or disease. Though inflammation is needed for healing, chronic inflammation is associated with <a href="https://doi.org/10.1016/j.neubiorev.2020.02.002">heart disease, arthritis, cancers</a> and <a href="https://www.autoimmuneinstitute.org/inflammation-a-driving-force-of-autoimmune-disease/">autoimmune diseases</a>. While single adults undoubtedly have very meaningful close relationships too, a healthy marriage by nature provides more opportunities for closeness and socialization, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3971932/">supporting the link between marriage and inflammation</a>.</p>
<p>When you dig deeper, gender seems to play a role as well. One study related to <a href="https://doi.org/10.1111/j.1741-3737.2012.01023.x">marital quality, gender and inflammation</a> found a connection between lower levels of spousal support and higher levels of inflammation for women, but not men. In another study, if couples used negative communication patterns, such as one partner making demands while the other partner withdraws, <a href="https://doi.org/10.1016/j.psyneuen.2022.105989">women but not men experienced heightened inflammation</a>.</p>
<h2>Marriage and longevity</h2>
<p>Married men and married women live, on average, <a href="https://doi.org/10.1016/j.ssmph.2020.100642">two years longer than their unmarried counterparts</a>. One reason for this longevity benefit is the <a href="https://doi.org/10.1186/1471-2458-14-533">influence of marital partners on healthy behaviors</a>. Study after study shows that married people <a href="https://www.theguardian.com/lifeandstyle/2016/apr/17/couples-healthier-wealthier-marriage-good-health-single-survey-research">eat better and are less likely to smoke and drink excessively</a>. All of these healthy behaviors help explain why married people tend to live longer. However, men married to women tend to see <a href="https://doi.org/10.1007/s13524-011-0032-5">additional longevity benefits than women married to men</a>, for several possible reasons.</p>
<p>For example, female spouses may be looking out for their male partners, <a href="https://doi.org/10.1177/0022146518790560">reinforcing healthy behaviors</a> and providing more opportunities for healthy choices. On the flip side, married men are <a href="https://doi.org/10.1037/0033-2909.127.4.472">less likely to attempt to influence</a> their wives’ health behaviors. </p>
<p>Women tend to <a href="https://doi.org/10.1093/geroni/igx025">take the lead in promoting healthy behaviors</a>, benefiting their husbands. Data suggests that men and women in same-gender relationships <a href="https://doi.org/10.1016/j.socscimed.2011.11.011">tend to engage in teamwork</a> to mutually promote positive health behaviors. Further, married men and women are <a href="https://doi.org/10.1177/0022146518790560">more likely to want to change their partners’ health behaviors</a>, such as exercise, especially if the spouses’ habits are worse than their own. These findings suggest that both the person and the partner’s gender matter.</p>
<figure class="align-center ">
<img alt="middle-aged man kisses neck of male partner while he is washing dishes at kitchen sink" src="https://images.theconversation.com/files/502227/original/file-20221220-11-m98bch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502227/original/file-20221220-11-m98bch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502227/original/file-20221220-11-m98bch.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502227/original/file-20221220-11-m98bch.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502227/original/file-20221220-11-m98bch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502227/original/file-20221220-11-m98bch.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502227/original/file-20221220-11-m98bch.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Data suggests that people in same-gender relationships engage in teamwork when it comes to health.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/senior-gay-couple-washing-dishes-together-royalty-free-image/1183447121">NicolasMcComber/E+ via Getty Images</a></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.1177/0963721414549043">Relationship quality</a> can also influence health behaviors. For example, in the context of exercise, both men and women who reported higher levels of marital support <a href="https://doi.org/10.1177/08982643221083083">were more likely to walk for exercise</a>. However, as men aged, the association between marital support and walking <a href="https://doi.org/10.1177/08982643221083083">became even stronger for them</a>, but the same was not true for married women.</p>
<h2>Cultural norms and caregiving</h2>
<p>To further understand how men’s health benefits from their wives, consider cultural norms that foster expectations that women will be the <a href="https://www.aarp.org/home-family/caregiving/info-01-2014/caregiving-family-gender-siblings-jacobs.html">primary caretaker in committed relationships</a>.</p>
<p>Middle-aged people, and in particular women, have also been described as the “<a href="https://www.kiplinger.com/personal-finance/604449/why-the-sandwich-generation-just-got-worse-for-women">sandwich generation</a>,” since they are often “sandwiched” between taking care of growing children and aging parents. Caregiving can take a <a href="https://doi.org/10.1016/j.cobeha.2019.02.002">toll on the immune system and one’s overall health</a>. Additionally, <a href="https://www.whiteswanfoundation.org/caregiving/how-the-role-of-caring-disproportionately-burdens-women">invisible labor related to child care</a> and household duties, which often disproportionately fall to women, can leave women with less time for self-care, <a href="https://doi.org/10.1177/00221465211028910">such as being physically active</a>.</p>
<p><a href="https://doi.org/10.1016/j.socscimed.2011.11.011">Women also take on more responsibilities</a> in terms of coordinating doctors’ appointments and promoting adherence to medical advice for their husbands than husbands do for their wives. However, <a href="https://doi.org/10.1093/geronb/gby087">men often increase their time spent caregiving</a> when their wives are ill. </p>
<h2>Of course, not all marriages are created equal</h2>
<p><a href="https://doi.org/10.1177/0963721414549043">Relationship quality</a> and <a href="https://doi.org/10.1177/00221465211028910">relationship conflict</a> also play important roles when it comes to marriage and health. Gendered socialization and power differences often lead to women’s thinking and <a href="https://www.unicef-irc.org/evidence-for-action/what-is-gender-socialization-and-why-does-it-matter/">caring about their relationships more than men</a>, causing women to take primary responsibility for managing relationship issues, while men take on less of the burden.</p>
<p>Research shows that women are also more likely to <a href="https://doi.org/10.1037/0033-2909.122.1.5">base their identities on their relationships</a>, and so when they experience marital conflict or other relationship issues, they experience more negative <a href="https://doi.org/10.1111/pere.12292">emotional and physical health</a> effects than men. This can include increased risk of <a href="https://doi.org/10.1037/a0019547">metabolic syndrome</a>, <a href="https://doi.org/10.1037/a0026902">inflammation</a> and <a href="https://doi.org/10.1097/PSY.0b013e3180f62357">cardiovascular disease</a>.</p>
<p>Does this mean that all men should get married to protect their health or that unmarried people can’t enjoy the same health benefits as those who have said “I do”?</p>
<p>Not at all. Unmarried people can, of course, enjoy good health and longevity. Creating and <a href="https://doi.org/10.1016/j.ssmph.2019.100425">maintaining strong social ties</a> and <a href="https://doi.org/10.1016/j.ssmph.2020.100676">engaging with one’s community</a> go a long way when it comes to health. Further, making the best lifestyle choices available, seeking preventive health care and reducing stress can help everyone live a longer, healthier life.</p><img src="https://counter.theconversation.com/content/190731/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Libby Richards has received funding from the National Institutes of Health, The American Nurses Foundation, and is currently funded through the Indiana Clinical and Translational Sciences Institute. She is affiliated with the American Public Health Association and the International Society of Behavioral Nutrition and Physical Activity. </span></em></p><p class="fine-print"><em><span>Melissa Franks receives funding from the Indiana Clinical and Translational Sciences Institute.</span></em></p><p class="fine-print"><em><span>Rosie Shrout receives funding from the Indiana Clinical and Translational Sciences Institute. She is affiliated with several organizations, including the International Association for Relationships Research, National Council on Family Relations, American Psychosomatic Society, Gerontological Society of America, and Society for Personality and Social Psychology. </span></em></p>Most marriage and health studies have focused on married men and women. But more recent studies examine relationships in which partners have the same gender identity, the same biological sex and who are gender diverse.Libby Richards, Associate Professor of Nursing, Purdue UniversityMelissa Franks, Associate Professor of Human Development and Family Studies, Purdue UniversityRosie Shrout, Assistant Professor of Human Development and Family Studies, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1846252022-08-10T12:18:22Z2022-08-10T12:18:22ZOld age isn’t a modern phenomenon – many people lived long enough to grow old in the olden days, too<figure><img src="https://images.theconversation.com/files/478361/original/file-20220809-16-3s77rh.jpg?ixlib=rb-1.1.0&rect=668%2C129%2C5728%2C2901&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">If you made it past early childhood, your chances got better to see your golden years.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/midwife-bathing-newborn-after-birth-in-royalty-free-illustration/1039652044">Grafissimo/DigitalVision Vectors via Getty Images</a></span></figcaption></figure><p>Every year I ask the college students in the course I teach about the <a href="https://scholarworks.wmich.edu/cgi/viewcontent.cgi?article=1011&context=tmg">14th-century Black Death</a> to imagine they are farmers or nuns or nobles in the Middle Ages. What would their lives have been like in the face of this terrifying disease that killed millions of people in just a few years?</p>
<p>Setting aside how they envision what it would be like to confront the plague, these undergrads often figure that during the medieval period they would already be considered middle-aged or elderly at the age of 20. Rather than being in the prime of life, they think they’d soon be decrepit and dead.</p>
<p>They’re reflecting a common misperception that long life spans in humans are very recent, and that no one in the past lived much beyond their 30s.</p>
<p>But that’s just not true. <a href="https://scholar.google.com/citations?user=5mhMQ-8AAAAJ&hl=en&oi=ao">I am a bioarchaeologist</a>, which means that I <a href="https://doi.org/10.1002/ajpa.23322">study human skeletons excavated from archaeological sites</a> to understand what life was like in the past. I’m especially interested in <a href="https://doi.org/10.1002/ajpa.23317">demography</a> – mortality (deaths), fertility (births) and migration – and how it was linked with <a href="https://doi.org/10.1073/pnas.0705460105">health conditions and diseases</a> such as the <a href="https://doi.org/10.1371/journal.pone.0096513">Black Death</a> hundreds or thousands of years ago. There’s physical evidence that plenty of people in the past lived long lives – just as long as some people do today.</p>
<h2>Bones record the length of a life</h2>
<p>One of the first steps in research about demography in the past is to estimate how old people were when they died. Bioarchaeologists do this using information about how your bones and teeth change as you get older.</p>
<p>For example, I look for changes to <a href="https://doi.org/10.1016/j.forsciint.2011.11.031">joints in the pelvis</a> that are common at older ages. Observations of these joints in people today whose ages we know allow us to estimate ages for people from archaeological sites with joints that look similar.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/478359/original/file-20220809-16-1w3he4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="jawbone with teeth, a tooth, and a microscopy view of layers within a tooth's cementum" src="https://images.theconversation.com/files/478359/original/file-20220809-16-1w3he4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478359/original/file-20220809-16-1w3he4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=268&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478359/original/file-20220809-16-1w3he4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=268&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478359/original/file-20220809-16-1w3he4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=268&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478359/original/file-20220809-16-1w3he4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=337&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478359/original/file-20220809-16-1w3he4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=337&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478359/original/file-20220809-16-1w3he4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=337&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A researcher can count the layers within a tooth that were added over time to determine how old a person lived to be.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Cementochronology.tif">Benoitbertrand1974/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Another way to estimate age is to use a microscope to count the yearly additions of a mineralized tissue called cementum on teeth. It’s similar to counting a tree’s rings to see how many years it lived. Using approaches like these, <a href="https://doi.org/10.1371/journal.pone.0096513">many</a> <a href="https://doi.org/10.1016/j.ijpp.2015.05.001">studies</a> have documented the existence of people who lived long lives in the past.</p>
<p>For example, by examining skeletal remains, anthropologist <a href="https://www.semanticscholar.org/author/Meggan-Bullock/36970527">Meggan Bullock</a> and colleagues found that in the city of Cholula, Mexico, between 900 and 1531, most people who <a href="https://doi.org/10.1002/ajpa.22329">made it to adulthood lived past the age of 50</a>.</p>
<p>And of course there are many examples from historical records of people who lived very <a href="https://www.medievalists.net/2022/05/most-important-people-middle-ages/">long lives in the past</a>. For example, the sixth-century Roman Emperor Justinian I <a href="https://www.worldhistory.org/article/782/justinians-plague-541-542-ce/">reportedly died at the age of 83</a>.</p>
<p>Analysis of the tooth development of an ancient anatomically modern <em>Homo sapiens</em> individual from Morocco suggests that our species has experienced <a href="https://doi.org/10.1073/pnas.0700747104">long life spans for at least the past 160,000 years</a>.</p>
<h2>Clearing up a math misunderstanding</h2>
<p>Given physical and historical evidence that many people did live long lives in the past, why does the misperception that everyone was dead by the age of 30 or 40 persist? It stems from confusion about the difference between individual life spans and life expectancy.</p>
<p><a href="https://ourworldindata.org/life-expectancy-how-is-it-calculated-and-how-should-it-be-interpreted">Life expectancy</a> is the average number of years of life remaining for people of a particular age. For example, <a href="https://jech.bmj.com/content/55/1/38">life expectancy at birth (age 0)</a> is the average length of life for newborns. Life expectancy at age 25 is how much longer people live on average given they’ve survived to age 25.</p>
<p>In medieval England, life expectancy at birth for boys born to families that owned land was a mere <a href="https://doi.org/10.1093/ije/dyi211">31.3 years</a>. However, <a href="https://doi.org/10.1080/08898480902790387">life expectancy at age 25</a> for landowners in medieval England was 25.7. This means that people in that era who celebrated their 25th birthday could expect to live until they were 50.7, on average – 25.7 more years. While 50 might not seem old by today’s standards, remember that this is an average, so many people would have lived much longer, into their 70s, 80s and even older.</p>
<p>Life expectancy is a population-level statistic that reflects the conditions and experiences of a huge variety of people with very different health conditions and behaviors, some who die at very young ages, some who live to be over 100 years old, and lots whose life spans fall somewhere in between. Life expectancy is not a promise (or a threat!) about the life span of any single person.</p>
<p>What some people don’t realize is that low life expectancy at birth for any population usually reflects very high rates of <a href="https://www.cdc.gov/reproductivehealth/maternalinfanthealth/infantmortality.htm">infant mortality</a>. That’s a measure of deaths in the first year of life. Given that life expectancies reflect averages for a population, a high number of deaths at very young ages will skew calculations of life expectancy at birth toward younger ages. But typically, many people in those populations who make it past the vulnerable infant and early childhood years can expect to live relatively long lives.</p>
<p>Advances in <a href="https://doi.org/10.1371/journal.pone.0262802">modern sanitation</a> – which reduce the spread of diarrheal diseases that are a major killer of infants – <a href="https://doi.org/10.1073/pnas.1413559111">and vaccinations</a> can greatly increase life expectancies.</p>
<p>Consider the effect of infant mortality on overall age patterns in two contemporary populations with dramatically different life expectancies at birth.</p>
<p><iframe id="aP2wK" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/aP2wK/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>In <a href="https://www.cia.gov/the-world-factbook/countries/afghanistan/">Afghanistan, life expectancy at birth</a> is low, at just over 53 years, and infant mortality is high, at almost 105 deaths for every 1,000 children born.</p>
<p>In <a href="https://www.cia.gov/the-world-factbook/countries/singapore/#people-and-society">Singapore, life expectancy at birth</a> is much higher, at over 86 years, and infant mortality is very low – fewer than two infants die for every 1,000 who are born. In both countries, people do survive to very old ages. But in Afghanistan, because so many more people die at very young ages, proportionally fewer people survive to old age. </p>
<h2>Living a long life has long been possible</h2>
<p>It’s incorrect to view long lives as a remarkable and unique characteristic of the “modern” era.</p>
<p>Knowing that people often did have long lives in the past might help you feel more connected with the past. For example, you can imagine multigenerational households and gatherings, with grandparents in Neolithic China or Medieval England bouncing their grandchildren on their knees and telling them stories about their own childhoods decades before. You might have more in common with people who lived long ago than you had realized.</p><img src="https://counter.theconversation.com/content/184625/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sharon DeWitte receives funding from the National Science Foundation.</span></em></p>Nasty, brutish – but not necessarily short. Here’s how archaeologists know plenty of people didn’t die young.Sharon DeWitte, Professor of Anthropology, University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1855832022-06-23T20:08:24Z2022-06-23T20:08:24ZWe helped track 77 species for up to 60 years to try to reveal the secrets of long life. And some don’t seem to age at all<figure><img src="https://images.theconversation.com/files/470484/original/file-20220623-7584-nu1tiw.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Mike Gardner</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Ever wondered about the secret to a long life? Perhaps understanding the lifespans of other animals with backbones (or “vertebrates”) might help us unlock this mystery.</p>
<p>You’ve probably heard turtles live a long (and slow) life. At 190 years, <a href="https://www.smithsonianmag.com/smart-news/at-190-jonathan-the-tortoise-is-the-worlds-oldest-living-land-animal-180979514/">Jonathan</a> the Seychelles giant tortoise might be the oldest land animal alive. But why do some animals live longer than others?</p>
<p>Research <a href="https://www.science.org/doi/10.1126/science.abm0151">published today</a> by myself and colleagues in the journal Science investigates the various factors that may affect longevity (lifespan) and ageing in reptiles and amphibians.</p>
<p>We used long-term data from 77 different species of reptiles and amphibians – all cold-blooded animals. Our work is a collaboration between more than 100 scientists with up to 60 years of data on animals that were caught, marked, released and re-caught.</p>
<p>These data were then compared to existing information on warm-blooded animals, and several different ideas about ageing emerged.</p>
<h2>What factors might be important?</h2>
<h1>Cold-blooded or warm-blooded</h1>
<p>One popular line of thought we investigated is the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4843886/">idea</a> that cold-blooded animals such as frogs, salamanders and reptiles live longer because they age more <em>slowly</em>.</p>
<p>These animals have to rely on external temperatures to help regulate their body temperature. As a result they have slower “metabolisms” (the rate at which they convert what they eat and drink into energy).</p>
<p>Animals that are small and warm-blooded, such as mice, age quickly since they have faster metabolisms – and turtles age slowly since they have slower metabolisms. By this logic, cold-blooded animals should have lower metabolisms than similar-sized warm-blooded ones. </p>
<p>However, we found cold-blooded animals don’t age more slowly than similar-sized warm-blooded ones. In fact, the variation in ageing in the reptiles and amphibians we looked at was much greater than previously predicted. So the reasons vertebrates age are more complex than this idea sets out. </p>
<h1>Environmental temperature</h1>
<p>Another related <a href="https://academic.oup.com/biolinnean/article/125/4/730/5145102?login=true">theory</a> is that environmental temperature itself could be a driver for longevity. For instance, animals in colder areas might be processing food more slowly and have periods of inactivity, such as with hibernation – leading to an overall increase in lifespan. </p>
<p>Under this scenario, both cold and warm-blooded animals in colder areas would live longer than animals in warmer areas. </p>
<p>We found this was true for reptiles as a group, but not for amphibians. Importantly, this finding has implications for the effects of global warming, which might lead to reptiles ageing faster in permanently warmer environments.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/470478/original/file-20220623-51865-930myg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The stripy brown small lizard sits on a rock" src="https://images.theconversation.com/files/470478/original/file-20220623-51865-930myg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470478/original/file-20220623-51865-930myg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470478/original/file-20220623-51865-930myg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470478/original/file-20220623-51865-930myg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470478/original/file-20220623-51865-930myg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470478/original/file-20220623-51865-930myg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470478/original/file-20220623-51865-930myg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Viviparous lizard (<em>Zootoca vivipara</em>) is one of the cold-blooded species we studied.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/viviparous-lizard-zootoca-vivipara-34699252">Shutterstock</a></span>
</figcaption>
</figure>
<h1>Protection</h1>
<p>One <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jeb.12143">suggestion</a> is that animals with certain types of protections, such as protruding spines, armour, venom or shells, also don’t age as fast and therefore live longer. </p>
<p>A lot of energy is put into producing these protections, which can allow animals to live longer by making them less vulnerable to predation. However, could it be the very fact of having these protections allows animals to age more slowly?</p>
<p>Our work found this to be true. It seems having such protections does lead to animals living longer. This is especially true for turtles, which have hard shell protection and incredibly long lifespans.</p>
<p>We’ll need to conduct more research to figure out why just having protections is linked to a longer life.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/470483/original/file-20220623-51187-mpi2xr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A crocodile sits on the bank of a river with its mouth open" src="https://images.theconversation.com/files/470483/original/file-20220623-51187-mpi2xr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470483/original/file-20220623-51187-mpi2xr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470483/original/file-20220623-51187-mpi2xr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470483/original/file-20220623-51187-mpi2xr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470483/original/file-20220623-51187-mpi2xr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470483/original/file-20220623-51187-mpi2xr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470483/original/file-20220623-51187-mpi2xr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">One species of crocodile studied, <em>Crocodylus johnsoni</em>, has a powerful armoured body with protruding scales that protect it from predation.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/freshwater-crocodile-crocodylus-johnstoni-species-endemic-1541741615">Shutterstock</a></span>
</figcaption>
</figure>
<h1>Reproduction</h1>
<p>Finally, it has been <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0066670">posited</a> that perhaps longevity is linked to how late into life an animal reproduces. </p>
<p>If they can keep reproducing later into life, then natural selection would drive this ability, generation to generation, allowing these animals to live longer than those that reproduce early and can’t continue to do so.</p>
<p>Indeed, we found animals that start producing offspring at a later age do seem to live longer lives. Sleepy lizards (or shinglebacks) are a great example. They don’t reproduce until they’re about five years old, and live until they’re close to 50!</p>
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Read more:
<a href="https://theconversation.com/breakthrough-allows-scientists-to-determine-the-age-of-endangered-native-fish-using-dna-162084">Breakthrough allows scientists to determine the age of endangered native fish using DNA</a>
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<h2>The challenge in understanding ageing</h2>
<p>To understand ageing, we need a lot of data on the same animals. That’s simply because if we want to know how long a species lives, we have to keep catching the same individuals over and over, across large spans of time. </p>
<p>This is “longitudinal” research. Luckily, it’s exactly what some scientists have committed themselves to. It’s also what my team is doing with sleepy lizards, <em>Tiliqua rugosa</em>. These lizards have been studied continuously at Bundey Bore station in the Mid North of South Australia since 1982. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/470225/original/file-20220622-3398-sv0ijc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/470225/original/file-20220622-3398-sv0ijc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470225/original/file-20220622-3398-sv0ijc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470225/original/file-20220622-3398-sv0ijc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470225/original/file-20220622-3398-sv0ijc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470225/original/file-20220622-3398-sv0ijc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470225/original/file-20220622-3398-sv0ijc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470225/original/file-20220622-3398-sv0ijc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The sleepy lizard is one of the species used in the longevity study. As far as we know, this species lives up to 50 years.</span>
<span class="attribution"><span class="source">Mike Gardner</span></span>
</figcaption>
</figure>
<p>Here, more than 13,000 lizards have been caught over 40 years of study. Some have been caught up to 60 times! But given the 45-year longevity of these lizards, we’ve been studying them for a shorter time than some of them live. By keeping the survey work going we might find they live even longer. </p>
<h2>Some animals’ chance of dying isn’t linked to age</h2>
<p>Another interesting part of this research was finding, for a range of animals, that their chance of dying is just as small when they’re quite old compared to when they’re young. This “negligible ageing” is found in at least one species across each of frogs, salamanders, lizards, crocodiles and, of course, in tortoises like Jonathon. </p>
<p>We’re not quite sure why this is. The next challenge is to find out – perhaps by analysing species genomes. Knowing some animals have negligible ageing means we can target these species for future investigations. </p>
<p>Understanding what drives long life in other animals might lead to different biomedical targets to study humans too. We might not live to Jonathan the tortoise’s age, but we could theoretically use this knowledge to develop therapies that help stop some of the ageing process in us. </p>
<p>For now, healthy eating and exercising remain surer ways to a longer life.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/the-search-to-extend-lifespan-is-gaining-ground-but-can-we-truly-reverse-the-biology-of-ageing-75127">The search to extend lifespan is gaining ground, but can we truly reverse the biology of ageing?</a>
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<img src="https://counter.theconversation.com/content/185583/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mike Gardner receives funding from the Australian Research Council. He is affiliated with The South Australian Museum. </span></em></p>Our research is countering some previous ideas about what factors might slow down ageing. Further study could help us create targeted treatments in humans too.Mike Gardner, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1847852022-06-21T10:12:45Z2022-06-21T10:12:45ZDo optimists really live longer? Here’s what the research says<figure><img src="https://images.theconversation.com/files/469985/original/file-20220621-16-b1wwi2.jpg?ixlib=rb-1.1.0&rect=13%2C20%2C4642%2C3078&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Women who reported themselves to have high levels of optimism lived longer on average.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/happy-senior-lady-sitting-on-wooden-458894395">FamVeld/ Shutterstock</a></span></figcaption></figure><p>Do you tend to see the glass as half full, rather than half empty? Are you always looking on the bright side of life? If so, you may be surprised to learn that this tendency could actually be good for your health.</p>
<p>A <a href="https://content.apa.org/record/2020-71981-001">number of studies</a> have shown that optimists enjoy higher levels of wellbeing, better sleep, lower stress and even better cardiovascular health and immune function. And now, <a href="https://pubmed.ncbi.nlm.nih.gov/35674052/">a recent study</a> has shown that being an optimist is linked to longer life. </p>
<p>To conduct their study, researchers tracked the lifespan of nearly 160,000 women aged between 50 to 79 for a period of 26 years. At the beginning of the study, the women completed a <a href="https://local.psy.miami.edu/people/faculty/ccarver/availbale-self-report-instruments/lot-r/">self-report measure of optimism</a>. Women with the highest scores on the measure were categorised as optimists. Those with the lowest scores were considered pessimists.</p>
<p>Then, in 2019, the researchers followed up with the participants who were still living. They also looked at the lifespan of participants who had died. What they found was that those who had the highest levels of optimism were more likely to live longer. More importantly, the optimists were also more likely than those who were pessimists to live into their nineties. Researchers refer to this as “exceptional longevity”, considering the average lifespan for women is about 83 years in developed countries. </p>
<p>What makes these findings especially impressive is that the results remained even after accounting for other factors known to predict a long life – including education level and economic status, ethnicity, and whether a person suffered from depression or other chronic health conditions. </p>
<p>But given this study only looked at women, it’s uncertain whether the same would be true for men. However, <a href="https://www.pnas.org/doi/abs/10.1073/pnas.1900712116">another study</a> which looked at both men and women also found that people with the highest levels of optimism enjoyed a lifespan that was between 11% and 15% longer than those who were the least optimistic. </p>
<h2>The fountain of youth?</h2>
<p>So why is it that optimists live longer? At first glance it would seem that it may have to do with their healthier lifestyle. </p>
<p>For example, <a href="https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.117.310828">research from several studies</a> has found that optimism is linked to eating a healthy diet, staying physically active, and being less likely to smoke cigarettes. These healthy behaviours are well known to improve heart health and <a href="https://www.who.int/news-room/fact-sheets/detail/noncommunicable-diseases">reduce the risk</a> for cardiovascular disease, which is a <a href="https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)">leading cause of death</a> globally. Adopting a healthy lifestyle is also <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3857242/">important for reducing the risk</a> of other potentially deadly diseases, such as diabetes and cancer. </p>
<figure class="align-center ">
<img alt="Two elderly women out for a walk together on a pier on a sunny day." src="https://images.theconversation.com/files/469986/original/file-20220621-11-wty41p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/469986/original/file-20220621-11-wty41p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469986/original/file-20220621-11-wty41p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469986/original/file-20220621-11-wty41p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469986/original/file-20220621-11-wty41p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469986/original/file-20220621-11-wty41p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469986/original/file-20220621-11-wty41p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Optimists tend to have healthier lifestyle habits.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/action-portrait-elderly-women-jogging-together-162594119">karelnoppe/ Shutterstock</a></span>
</figcaption>
</figure>
<p>But having a healthy lifestyle may only be part of the reason optimists live a longer than average life. This latest study found that lifestyle only accounted for 24% of the link between optimism and longevity. This suggests a number of other factors affect longevity for optimists.</p>
<p>Another possible reason could be due to the way optimists manage stress. When faced with a stressful situation, optimists tend to deal with it head-on. They <a href="https://pubmed.ncbi.nlm.nih.gov/16859439/">use adaptive coping strategies</a> that help them resolve the source of the stress, or view the situation in a less stressful way. For example, optimists will problem-solve and plan ways to deal with the stressor, call on others for support, or try to find a “silver lining” in the stressful situation.</p>
<p>All of these approaches are well-known to reduce feelings of stress, as well as the biological reactions that occur when we feel stressed. It’s these <a href="https://www.apa.org/topics/stress/body">biological reactions to stress</a> –- such as elevated cortisol (sometimes called the “stress hormone”), increased heart rate and blood pressure, and impaired immune system functioning –- that can take a toll on health over time and increase the risk for developing <a href="https://www.sciencedirect.com/science/article/pii/S0889159115004316?via%3Dihub">life-threatening diseases</a>, such as cardiovascular disease. In short, the way optimists cope with stress may help protect them somewhat against its harmful effects. </p>
<h2>Looking on the bright side</h2>
<p>Optimism is typically viewed by researchers as a relatively stable personality trait that is determined by both <a href="https://www.cambridge.org/core/journals/twin-research-and-human-genetics/article/sex-differences-in-the-genetic-architecture-of-optimism-and-health-and-their-interrelation-a-study-of-australian-and-swedish-twins/58F21AA11943D44B4BA4C63A966E6AC7#">genetic</a> and early childhood influences (such as having a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6541423/">secure and warm relationship</a> with your parents or caregivers). But if you’re not naturally prone to seeing the glass as half full, there are some ways you can increase your <a href="https://www.tandfonline.com/doi/abs/10.1080/17439760.2016.1221122?journalCode=rpos20">capacity to be optimistic</a>.</p>
<p>Research shows optimism can change over time, and can be cultivated by engaging in simple exercises. For example, visualising and then writing about your “<a href="https://www.psychologytoday.com/us/blog/what-matters-most/201303/what-is-your-best-possible-self">best possible self</a>” (a future version of yourself who has accomplished your goals) is a technique that studies have found can <a href="https://www.tandfonline.com/doi/full/10.1080/17439760.2016.1221122">significantly increase optimism</a>, at least temporarily. But for best results, the goals need to be both positive and reasonable, rather than just wishful thinking. Similarly, simply <a href="https://www.tandfonline.com/doi/abs/10.3200/SOCP.149.3.349-364">thinking about positive future events</a> can also be effective for boosting optimism.</p>
<p>It’s also crucial to temper any expectations for success with an accurate view of what you can and can’t control. Optimism is reinforced when we experience the positive outcomes that we expect, and <a href="https://psycnet.apa.org/record/1970-20680-001">can decrease</a> when these outcomes aren’t as we want them to be. Although more research is needed, it’s possible that regularly envisioning yourself as having the best possible outcomes, and taking realistic steps towards achieving them, can help develop an optimistic mindset. </p>
<p>Of course, this might be easier said than done for some. If you’re someone who isn’t naturally optimistic, the best chances to improve your longevity is by <a href="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003332">living a healthy lifestyle</a> by staying physically active, eating a healthy diet, managing stress, and getting a good night’s sleep. Add to this cultivating a more optimistic mindset and you might further increase your chances for a long life.</p><img src="https://counter.theconversation.com/content/184785/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fuschia Sirois receives funding from Economic and Social Research Council, UK.</span></em></p>According to a recent study, optimists were more likely to live into their nineties.Fuschia Sirois, Professor in Social & Health Psychology, Durham UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1764942022-02-08T19:03:46Z2022-02-08T19:03:46ZChanging your diet could add ten years to your life – new research<p>Everyone wants to live longer. And we’re often told that the key to doing this is making healthier lifestyle choices, such as exercising, avoiding smoking and not drinking too much alcohol. Studies have also shown that diet can <a href="https://content.iospress.com/articles/mediterranean-journal-of-nutrition-and-metabolism/mnm180225">increase lifespan</a>. </p>
<p>A <a href="http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003889">new study</a> has found that eating healthier could extend lifespan by six to seven years in middle-aged age adults, and in young adults, could increase lifespan by about ten years. </p>
<p>The researchers brought together data from many studies that looked at diet and longevity, alongside data from the <a href="https://www.healthdata.org/gbd/2019">Global Burden of Disease</a> study, which provides a summary of population health from many countries. Combining this data, the authors were then able to estimate how life expectancy varied with continuous changes in intake of fruit, vegetables, whole grains, refined grains, nuts, legumes, fish, eggs, dairy, red meat, processed meat and sugary drinks. </p>
<p>The authors were then able to produce an optimal diet for longevity, which they then compared with the typical western diet – which mostly contains high amounts of processed foods, red meat, high-fat dairy products, high-sugar foods, pre-packed foods and low fruit and vegetable intake. According to their research, an optimal diet included more legumes (beans, peas and lentils), whole grains (oats, barley and brown rice) and nuts, and less red and processed meat. </p>
<p>The researchers found that eating an optimal diet from age 20 would increase life expectancy by more than a decade for women and men from the US, China and Europe. They also found that changing from a western diet to the optimal diet at age 60 would increase life expectancy by eight years. For 80-year-olds, life expectancy could increase by almost three and a half years. </p>
<p>But given it isn’t always possible for people to completely change their diet, the researchers also calculated what would happen if people changed from a western diet to a diet that was halfway between the optimal diet and the typical western diet. They found that even this kind of diet – which they called a “feasibility approach diet” – could still increase life expectancy for 20-year-olds by just over six years for women and just over seven years for men.</p>
<figure class="align-center ">
<img alt="A table which shows how many grams of each food group a person should aim to consume on each of the three diets the researchers looked at in their study." src="https://images.theconversation.com/files/445094/original/file-20220208-21-2q91vx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/445094/original/file-20220208-21-2q91vx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/445094/original/file-20220208-21-2q91vx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/445094/original/file-20220208-21-2q91vx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/445094/original/file-20220208-21-2q91vx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/445094/original/file-20220208-21-2q91vx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/445094/original/file-20220208-21-2q91vx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A table showing the typical amount of foods people should aim to consume daily on each type of diet.</span>
<span class="attribution"><span class="source">Laura Brown</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These results show us that making long-term diet changes at any age may have substantial benefits to life expectancy. But the gains are largest if these changes start early in life. </p>
<h2>Full picture?</h2>
<p>The life expectancy estimates this study makes come from the most thorough and recent meta-analyses (a study that combines the results of multiple scientific studies) on diet and mortality. </p>
<p>While meta-analyses are, in many cases, the best evidence because of the amount of data analysed, they still produce assumptions with the data, which may cause important differences between studies to be ignored. It’s also worth noting that the evidence for reducing consumption of eggs and white meat was of a lower quality than the evidence they had for whole grains, fish, processed meats and nuts. </p>
<p>There are also a few things the study didn’t take into account. First, to see these benefits, people needed to make changes to their diet within a ten-year period. This means it’s uncertain if people may still see benefits to their lifespan if they make changes to their diet over a longer period of time. The study also didn’t take past ill-health into account, which can affect life expectancy. This means that the benefits of diet on life expectancy only reflect an average and may be different for each person depending on a variety of other factors, such as ongoing health issues, genetics and lifestyle, such as smoking, drinking alcohol and exercise.</p>
<p>But the evidence the researchers looked at was still robust and drawn from many studies on this subject. These findings also align with <a href="https://content.iospress.com/articles/mediterranean-journal-of-nutrition-and-metabolism/mnm180225#ref181">previous research</a> which has shown that modest but long-term improvements to diet and lifestyle can have <a href="https://pubmed.ncbi.nlm.nih.gov/20421558/">significant health benefits</a> – including longevity.</p>
<p>It’s not yet entirely clear all the mechanisms that explain why diet can improve lifespan. But the optimal diet that the researchers uncovered in this study includes many foods that are high in antioxidants. <a href="https://content.iospress.com/articles/mediterranean-journal-of-nutrition-and-metabolism/mnm180225#ref18">Some research</a> in human cells suggests that these substances may slow or prevent damage to cells, which is one cause of ageing. However, research in this area is still ongoing, so it’s uncertain whether antioxidants that we consume as part of our diet will have the same effect. Many of the foods included within this study also have anti-inflammatory properties, which may also delay the onset of various diseases – and the ageing process. </p>
<p>Of course, changing your diet completely can be difficult. But even introducing some of the foods shown to increase longevity may still have some benefit.</p><img src="https://counter.theconversation.com/content/176494/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Laura Brown does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Diets high in legumes, whole grains, nuts and less red and processed meat were shown to be more beneficial for longevity.Laura Brown, Senior Lecturer in Nutrition, Food, and Health Sciences, Teesside UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1328242020-07-01T12:29:59Z2020-07-01T12:29:59ZFrom marmots to mole-rats to marmosets – studying many genes in many animals is key to understanding how humans can live longer<figure><img src="https://images.theconversation.com/files/340715/original/file-20200609-21196-112b33n.jpg?ixlib=rb-1.1.0&rect=7%2C7%2C5144%2C3561&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Is there a genetic switch that can help reverse the aging process?</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/portrait-of-woman-holding-black-and-white-younger-royalty-free-image/1149473225?adppopup=true">Dimitri Otis / Getty Images</a></span></figcaption></figure><p>Much of longevity and aging research focuses on studying extremely long-lived species, including <a href="https://www.nature.com/articles/ncomms3212">bats</a>, <a href="https://www.nature.com/articles/nature10533/">naked mole-rats</a> and <a href="https://www.sciencedirect.com/science/article/pii/S2211124714010195">bowhead whales</a>, to find genetic changes that contribute to long life. </p>
<p>However, such work has yielded highly species-specific genetic changes that are not generalizable to other species, including humans. As a graduate student, I have studied growing evidence, including recent work from my advisers’ labs (<a href="http://chikinalab.org/index.html">Maria Chikina</a> and <a href="http://clark.genetics.utah.edu/">Nathan Clark</a>), that supports the hypothesis that lifespan is a complex and highly context-dependent trait that calls for a shift in how biologists think about aging.</p>
<h2>Old age: The human problem</h2>
<p>Aging is the process by which the likelihood of death increases the longer an organism is alive. In mammals, aging is hallmarked by several <a href="https://doi.org/10.1016/j.cell.2013.05.039">molecular changes</a>, including the breakdown of DNA, a shortage of stem cells and malfunctioning proteins. </p>
<p>Numerous theories that exist to explain why aging happens fall into <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995895/">two categories</a>. “Wear-and-tear” theories postulate that essential processes simply wear out over time. On the other hand, “programmed death” theories assert that specific genes or processes are designed to drive aging.</p>
<p>Traditional definitions and aging theories are human-centric, and when we examine aging from a <a href="https://doi.org/10.1038/nature12789">cross-species perspective</a>, it becomes clear that human aging is unique. In fact, among animals there is no typical way to age. </p>
<p>Humans show low mortality rates until a sharp spike in mortality at very old age, around 80 years. Most mammals have relatively less increase in mortality with age and more consistent mortality through their lifespans. Some mammals, such as the tundra vole and the yellow-bellied marmot, show <a href="https://doi.org/10.1038/nature12789">virtually no increase in mortality with age</a>. In other words, older individuals are equally as likely to die as younger individuals, possibly because aging does not impact survival.</p>
<p>Current aging theories fail to explain the full complexity of aging across all mammals, let alone the tree of life. Such diversity not only highlights the complexity of aging and longevity but also makes it difficult to apply knowledge gained about one species to increase lifespan in another.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344840/original/file-20200630-103645-10xifz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344840/original/file-20200630-103645-10xifz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=432&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344840/original/file-20200630-103645-10xifz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=432&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344840/original/file-20200630-103645-10xifz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=432&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344840/original/file-20200630-103645-10xifz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=543&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344840/original/file-20200630-103645-10xifz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=543&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344840/original/file-20200630-103645-10xifz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=543&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A bowhead whale and a surfer in Vrangel Bay. Bowhead whales, also known as Greenland right whales, can weigh from 75 to 100 tonnes.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/bowhead-whale-and-a-sup-surfer-in-the-vrangel-bay-50km-of-news-photo/1019871652?adppopup=true">Yuri Smityuk\TASS via Getty Images</a></span>
</figcaption>
</figure>
<h2>An overabundance of ‘longevity genes’</h2>
<p>Studies of exceptionally long-lived species have produced a plethora of so-called longevity genes. One such gene, called the insulin-like growth factor 1, or IGF1, receptor gene, promotes cell growth. IGF1 was originally associated with long life in <a href="https://www.nature.com/articles/ncomms3212">bats</a> and also increases lifespan in <a href="https://doi.org/10.3389/fendo.2019.00027">worms and mice</a>. However, IGF1 may have the <a href="https://doi.org/10.1038/nrendo.2013.67">opposite effect</a> in humans, because too much IGF1 may increase age-related illnesses like diabetes and cancer.</p>
<p>[<em><a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=experts">Expertise in your inbox. Sign up for The Conversation’s newsletter and get expert takes on today’s news, every day.</a></em>]</p>
<p>Another potential longevity gene called the ERCC1 gene produces a protein that helps repair DNA. The <a href="https://doi.org/10.1016/j.celrep.2014.12.008">bowhead whale</a>, the longest-lived mammal at 211 years, has a mutation in the ERCC1 gene that may contribute to the species’ exceptionally long lifespan, but the mutation is not shared by other long-lived species. Elephants have <a href="https://doi.org/10.7554/eLife.11994">19 copies of the TP53 gene</a>, an essential cancer prevention gene, but adding even one extra TP53 gene to mice <a href="https://doi.org/10.1182/blood-2006-03-010413">accelerates aging because stem cells are slower to regenerate</a>.</p>
<p>Longevity genes can be inconsistent even within a single species. Studies that hunt for genetic changes common in long-lived humans, and absent from humans who lived shorter lives, have not delivered a master longevity gene. The genes detected are <a href="https://doi.org/10.1007/s00439-013-1342-z">largely inconsistent across studies</a> and rely heavily on the subpopulation of humans sampled and the precise definition of “exceptionally long-lived.”</p>
<h2>So how do we find longevity genes?</h2>
<p><a href="https://doi.org/10.7554/eLife.51089">My recent work</a> underscores the argument that aging researchers should not be looking for individual longevity genes. Instead biologists should be seeking many genes with similar functions working together to control longevity. Further, an effective search should not just focus on a single species, but many, to avoid species-specific elements. </p>
<p>As part of a research study, I used genomes from 61 mammals to detect genes that evolved in tandem with the evolution of extreme lifespan, thereby uncovering longevity-related changes universal across all mammals. At the gene level, I found few longevity genes, which makes sense in light of previous work. There is probably no single gene in all mammals that regulates lifespan.</p>
<p>When I looked at the big picture, however, and considered groups of genes working together to perform a similar function, I found a strong association between longevity and pathways related to controlling cancer. Examples of such groups of genes are those involved in regulating the cell cycle and programmed cell death, and pathways for immune function and DNA repair. All of these functions have been <a href="https://doi.org/10.1016/j.cell.2013.05.039">previously implicated</a> in lifespan regulation in a wide variety of studies. </p>
<p>My work highlights the importance of a new perspective on aging and longevity.</p>
<p>Species-specific and human genome-wide association studies have limitations that may be enriched by a broader analyses, both in terms of the genomic elements studied and the species considered. Rather than searching for a single gene in a single species that drives increased lifespan, broadening the search to many genes across many species can bring new insights. </p>
<p>One <a href="https://doi.org/10.1007/s11357-011-9340-3">modified genome-wide approach</a> using information about functional relationships among genes found an association between the human IGF1 pathway and longevity scattered over nine genes, a key example of broadening the search for the genetics of lifespan beyond single genes. </p>
<p>Similarly, <a href="https://doi.org/10.1016/j.semcdb.2017.08.007">comparative studies</a> like mine that interrogate genetic similarities and differences among long-lived species have repeatedly demonstrated the power to detect longevity-related genetic changes spread over many genes and shared across many species.</p>
<p>While there may not be a proverbial genetic “Fountain of Youth” – one single genetic change that magically allows us all to live longer – scientists like me are continually improving our strategies to study longevity so we can someday all have longer, healthier lives.</p><img src="https://counter.theconversation.com/content/132824/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amanda Kowalczyk was supported by funding provided by NIH R01HG009299, NIH U54 HG008540, and HHMI T32 EB009403 while completing the research described in this article.</span></em></p>Is there a single master gene that controls longevity in all mammals? Or are ‘Fountain of Youth’ genes little more than a myth?Amanda Kowalczyk, Postdoctoral Researcher, University of PittsburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1290682020-01-15T19:08:18Z2020-01-15T19:08:18ZDon’t die wondering: apps may soon be able to predict your life expectancy, but do you want to know?<figure><img src="https://images.theconversation.com/files/310160/original/file-20200115-151844-1ole8rh.jpg?ixlib=rb-1.1.0&rect=46%2C23%2C3833%2C2681&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Monaco and Japan have some of the highest life expectancies in the world. But calculating an individual's life expectancy will require taking data analysis several steps further.</span> <span class="attribution"><span class="source">SHUTTERSTOCK</span></span></figcaption></figure><p><em>When will I die?</em></p>
<p>This question has endured across cultures and civilisations. It has given rise to a plethora of religions and spiritual paths over thousands of years, and more recently, <a href="https://apps.apple.com/us/app/when-will-i-die/id1236569653">some highly amusing apps</a>. </p>
<p>But this question now prompts a different response, as technology slowly brings us closer to accurately predicting the answer. </p>
<p>Predicting the lifespan of people, or their “Personal Life Expectancy” (PLE) would greatly alter our lives. </p>
<p>On one hand, it may have benefits for policy making, and help optimise an individual’s health, or the services they receive. </p>
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<strong>
Read more:
<a href="https://theconversation.com/were-not-just-living-for-longer-were-staying-healthier-for-longer-too-118588">We're not just living for longer – we're staying healthier for longer, too</a>
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<p>But the potential misuse of this information by the government or private sector poses major risks to our rights and privacy.</p>
<p>Although generating an accurate life expectancy is currently difficult, due to the complexity of factors underpinning lifespan, emerging technologies could make this a reality in the future.</p>
<h2>How do you calculate life expectancy?</h2>
<p>Predicting life expectancy is not a new concept. <a href="http://www.bbc.com/travel/story/20170807-living-in-places-where-people-live-the-longest">Experts do this</a> at a population level by classifying people into groups, often based on region or ethnicity. </p>
<p>Also, tools such as <a href="https://www.nature.com/articles/s41598-018-23534-9">deep learning</a> and <a href="https://mipt.ru/english/news/scientists_use_ai_to_predict_biological_age_based_on_smartphone_and_wearables_data">artificial intelligence</a> can be used to consider complex variables, such as biomedical data, to predict someone’s biological age. </p>
<p>Biological age refers to how “old” their body is, rather than when they were born. A 30-year-old who smokes heavily may have a biological age closer to 40.</p>
<p><a href="https://www.mdpi.com/2227-7080/6/3/74/htm">Calculating a life expectancy reliably</a> would require a sophisticated system that considers a breadth of environmental, geographic, genetic and lifestyle factors – <a href="https://www1.health.gov.au/internet/publications/publishing.nsf/Content/oatsih-hpf-2012-toc%7Etier1%7Elife-exp-wellb%7E119">all of which have influence</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/310166/original/file-20200115-151848-pc2cam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/310166/original/file-20200115-151848-pc2cam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/310166/original/file-20200115-151848-pc2cam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310166/original/file-20200115-151848-pc2cam.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310166/original/file-20200115-151848-pc2cam.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310166/original/file-20200115-151848-pc2cam.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310166/original/file-20200115-151848-pc2cam.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310166/original/file-20200115-151848-pc2cam.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The use of devices such as fitness trackers will become crucial in predicting personal life expectancy in the future.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/healthy-lady-run-away-angel-death-329261456">Shutterstock</a></span>
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<p>With <a href="https://builtin.com/artificial-intelligence/machine-learning-healthcare">machine learning</a> and artificial intelligence, it’s becoming feasible to analyse larger quantities of data. The use of deep learning and cognitive computing, such as with <a href="https://www.ibm.com/watson-health">IBM Watson</a>, helps doctors make more accurate diagnoses than using human judgement alone. </p>
<p>This, coupled with <a href="https://www.cio.com/article/3273114/what-is-predictive-analytics-transforming-data-into-future-insights.html">predictive analytics</a> and increasing computational power, means we may soon have systems, or even apps, that can calculate life expectancy.</p>
<h2>There’s an app for that</h2>
<p>Much like <a href="https://www.mdanderson.org/for-physicians/clinical-tools-resources/clinical-calculators.html">existing tools</a> that predict cancer survival rates, in the coming years we may see apps attempting to analyse data to predict life expectancy.</p>
<p>However, they will not be able to provide a “death date”, or even a year of death.</p>
<p>Human behaviour and activities are so unpredictable, it’s almost impossible to measure, classify and predict lifespan. A personal life expectancy, even a carefully calculated one, would only provide a “natural life expectancy” based on generic data optimised with personal data.</p>
<p>The key to accuracy would be the quality and quantity of data available. Much of this would be taken directly from the user, including gender, age, weight, height and ethnicity.</p>
<p>Access to real-time sensor data through fitness trackers and smart watches could also monitor activity levels, heart rate and blood pressure. This could then be coupled with lifestyle information such as occupation, socioeconomic status, exercise, diet and family medical history. </p>
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Read more:
<a href="https://theconversation.com/your-local-train-station-can-predict-health-and-death-54946">Your local train station can predict health and death</a>
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<p>All of the above could be used to classify an individual into a generic group to calculate life expectancy. This result would then be refined over time through the analysis of personal data, updating a user’s life expectancy and letting them monitor it.</p>
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<img alt="" src="https://images.theconversation.com/files/308303/original/file-20191230-11891-nswi58.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308303/original/file-20191230-11891-nswi58.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=176&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308303/original/file-20191230-11891-nswi58.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=176&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308303/original/file-20191230-11891-nswi58.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=176&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308303/original/file-20191230-11891-nswi58.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=221&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308303/original/file-20191230-11891-nswi58.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=221&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308303/original/file-20191230-11891-nswi58.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=221&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">This figure shows how an individual’s life expectancy might change between two points in time (F and H) following a lifestyle improvement, such as weight loss.</span>
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<h2>Two sides of a coin</h2>
<p>Life expectancy predictions have the potential to be beneficial to individuals, health service providers and governments.</p>
<p>For instance, they would make people more aware of their general health, and its improvement or deterioration over time. This may motivate them to make healthier lifestyle choices.</p>
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Read more:
<a href="https://theconversation.com/faster-more-accurate-diagnoses-healthcare-applications-of-ai-research-114000">Faster, more accurate diagnoses: Healthcare applications of AI research</a>
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<p>They could also be used by insurance companies to provide individualised services, such as how some car insurance companies use <a href="https://www.theguardian.com/money/2017/dec/16/motoring-myths-black-boxes-telematics-insurance">black-box technology</a> to reduce premiums for more cautious drivers.</p>
<p>Governments may be able to use predictions to more efficiently allocate limited resources, such as social welfare assistance and health care funding, to individuals and areas of greater need.</p>
<p>That said, there’s a likely downside. </p>
<p>People <a href="https://www.theatlantic.com/health/archive/2017/11/the-existential-slap/544790/">may become distressed</a> if their life expectancy is unexpectedly low, or at the thought of having one at all. This raises concerns about how such predictions could impact those who experience or are at risk of mental health problems. </p>
<p>Having people’s detailed health data could also let insurance companies more accurately profile applicants, <a href="https://www.abc.net.au/news/2019-07-08/fitness-tracker-used-to-set-health-insurance-premiums/11287126">leading to discrimination against groups or individuals</a>. </p>
<p>Also, pharmaceutical companies could coordinate targeted medical campaigns based on people’s life expectancy. And governments could choose to tax individuals differently, or restrict services for certain people.</p>
<h2>When will it happen?</h2>
<p>Scientists have been working on ways to <a href="https://towardsdatascience.com/what-really-drives-higher-life-expectancy-e1c1ec22f6e1">predict human life expectancy</a> for many years. </p>
<p>The solution would require input from specialists including demographers, health scientists, data scientists, IT specialists, programmers, medical professionals and statisticians.</p>
<p>While the collection of enough data will be challenging, we can likely expect to see advances in this area in the coming years.</p>
<p>If so, issues related to data compliance, as well and collaboration with government and state agencies will need to be carefully managed. Any system predicting life expectancy would handle highly sensitive data, raising ethical and privacy concerns.</p>
<p>It would also attract cybercriminals, and various other security threats.</p>
<p>Moving forward, the words of Jurassic Park’s Dr Ian Malcolm spring to mind:</p>
<blockquote>
<p>Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should.</p>
</blockquote><img src="https://counter.theconversation.com/content/129068/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Predicting life expectancy remains in the realm of science fiction, but it may soon be possible. Are we prepared for such information? And who else would benefit from this knowledge?James Jin Kang, Lecturer, Edith Cowan UniversityPaul Haskell-Dowland, Associate Dean (Computing and Security), Edith Cowan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1286232019-12-12T18:56:56Z2019-12-12T18:56:56ZA new study shows an animal’s lifespan is written in the DNA. For humans, it’s 38 years<figure><img src="https://images.theconversation.com/files/306247/original/file-20191211-95149-xw1kep.jpg?ixlib=rb-1.1.0&rect=14%2C0%2C4905%2C3280&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A genetic "clock" lets scientists estimate how long extinct creatures lived. Wooly mammoths could expect around 60 years.</span> <span class="attribution"><span class="source">Australian Museum</span></span></figcaption></figure><p>Humans have a “natural” lifespan of around 38 years, according to a new method we have developed for estimating the lifespans of different species by analysing their DNA. </p>
<p>Extrapolating from genetic studies of species with known lifespans, we found that the extinct woolly mammoth probably lived around 60 years and bowhead whales can expect to enjoy more than two and a half centuries of life. </p>
<p>Our research, <a href="https://www.nature.com/articles/s41598-019-54447-w">published today in Scientific Reports</a>, looked at how DNA changes as an animal ages – and found that it varies from species to species and is related to how long the animal is likely to live.</p>
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Read more:
<a href="https://theconversation.com/the-search-to-extend-lifespan-is-gaining-ground-but-can-we-truly-reverse-the-biology-of-ageing-75127">The search to extend lifespan is gaining ground, but can we truly reverse the biology of ageing?</a>
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<h2>The mystery of ageing</h2>
<p>The ageing process is very important in biomedical and ecological research. As animals grow older, they experience a decline of biological functions, which limits their lifespan. Until now it has been difficult to determine how many years an animal can live. </p>
<p>DNA is the blueprint of living organisms and it is an obvious place to seek insights into ageing and lifespan. However, no-one has been able to find differences in DNA sequences that account for differences in lifespans.</p>
<p>Lifespans among vertebrates varies greatly. The pygmy goby (<em>Eviota sigillata</em>) is a small fish that lives only eight weeks, whereas individual Greenland sharks (<em>Somniosus microcephalus</em>) have been found that lived for more than 400 years. </p>
<p>Knowing the lifespan of wild animals is fundamental for wildlife management and conservation. For endangered species, lifespan can be used to understand what populations are viable. In industries such as fisheries, lifespan is used in population models to determine catch limits. </p>
<p>However, the lifespan of most animals is unknown. Most estimates come from a small number of individuals living in captivity whose ages at death were known. For long-lived species it is difficult to obtain a lifespan as they may outlive a generation of researchers. </p>
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Read more:
<a href="https://theconversation.com/tick-tock-how-stress-speeds-up-your-chromosomes-ageing-clock-127728">Tick, tock... how stress speeds up your chromosomes' ageing clock</a>
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<h2>Using changes in DNA to measure age</h2>
<p>Over the past few years researchers have developed DNA “clocks” that can determine how old an animal is using a special type of change in the DNA called DNA methylation. </p>
<p>DNA methylation does not change the underlying sequence of a gene but controls whether it is active. Other researchers have shown that DNA methylation in specific genes is associated with the maximum lifespan of some mammals such as primates. </p>
<p>Despite DNA methylation being linked to ageing and lifespan, no research until now has used it as a method to estimate the lifespan of animals.</p>
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Read more:
<a href="https://theconversation.com/it-looks-like-an-anchovy-fillet-but-this-ancient-creature-helps-us-understand-how-dna-works-107353">It looks like an anchovy fillet but this ancient creature helps us understand how DNA works</a>
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<p>In our research, we have used 252 genomes (full DNA sequences) of vertebrate species that other researchers have assembled and made publicly available in an <a href="https://www.ncbi.nlm.nih.gov/genome/">online database</a>. We then compared these genomes to <a href="https://genomics.senescence.info/species/">another database</a> of known animal lifespans. </p>
<p>Using this data, we found that we could estimate the lifespan of vertebrate species by looking at where DNA methylation occurs in 42 particular genes. This method also lets us estimate the lifespans of long-lived and extinct species. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306222/original/file-20191211-95138-nfsxg8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306222/original/file-20191211-95138-nfsxg8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306222/original/file-20191211-95138-nfsxg8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306222/original/file-20191211-95138-nfsxg8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306222/original/file-20191211-95138-nfsxg8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306222/original/file-20191211-95138-nfsxg8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=523&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306222/original/file-20191211-95138-nfsxg8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=523&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306222/original/file-20191211-95138-nfsxg8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=523&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Using DNA analysis, scientists can now estimate the lifespans of long-lived and extinct species.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Extinct species</h2>
<p>We found the lifespan of the bowhead whale, thought to be the world’s longest lived mammal, is 268 years. This estimate is 57 years higher than the oldest individual that has been found, so they may have a much longer lifespan than previously thought. </p>
<p>We also found the extinct woolly mammoth had a lifespan of 60 years, similar to the 65-year span of the modern-day African elephant. </p>
<p>The extinct Pinta Island giant tortoise had a lifespan of 120 years by our estimate. The last member of this species, Lonesome George, died in 2012 at age 112. </p>
<p>Interestingly, we found Neanderthals and Denisovans, which are extinct species closely related to modern humans, had a maximum lifespan of 37.8 years. </p>
<p>Based on DNA, we also estimated a “natural” lifespan modern humans of 38 years. This matches some anthropological estimates for early modern humans. However, humans today may be an exception to this study as advances in medicine and lifestyle have extended the average lifespan. </p>
<p>As more scientists assemble the genomes of other animals, our method means their lifespans can readily be estimated. This has huge ecological and conservation significance for many species which require better wildlife management.</p><img src="https://counter.theconversation.com/content/128623/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Benjamin Mayne receives funding from CSIRO Environomics Future Science Platform and is supported by the the North West Shelf Flatback Turtle Conservation Program (<a href="https://flatbacks.dbca.wa.gov.au/about">https://flatbacks.dbca.wa.gov.au/about</a>). </span></em></p>Knowing an animal’s normal lifespan is hugely important for conservation efforts, but it’s harder to find out than you’d think.Benjamin Mayne, Molecular biologist and bioinformatician, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/986852018-07-23T10:21:57Z2018-07-23T10:21:57ZHow old is my pet in dog years or cat years? A veterinarian explains<figure><img src="https://images.theconversation.com/files/228459/original/file-20180719-142428-2hinnw.jpg?ixlib=rb-1.1.0&rect=509%2C0%2C4270%2C3425&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Did anyone check the number of candles on here?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dog-race-french-bulldogs-on-birthday-398117596">KikoStock/Shutterstock.com</a></span></figcaption></figure><p>“Just how old do you think my dog is in dog years?” is a question I hear on a regular basis. People love to anthropomorphize pets, attributing human characteristics to them. And most of us want to extend our animal friends’ healthy lives for as long as possible.</p>
<p>It may seem like sort of a silly thing to ponder, born out of owners’ love for their pets and the <a href="https://www.avma.org/KB/Resources/Reference/human-animal-bond/Pages/Human-Animal-Bond-AVMA.aspx">human-animal bond</a> between them. But determining a pet’s “real” age is actually important because it helps veterinarians like me recommend life-stage specific healthcare for our animal patients.</p>
<p>There’s an old myth that one regular year is like seven years for dogs and cats. There’s a bit of logic behind it. People observed that with optimal healthcare, an <a href="https://ebusiness.avma.org/files/productdownloads/PetsAgeFaster.pdf">average-sized, medium dog</a> would on average live one-seventh as long as its human owner – and so the seven “dog years” for every “human year” equation was born. </p>
<p>Not every dog is “average-sized” though so this seven-year rule was an oversimplification from the start. Dogs and cats age differently not just from people but also from each other, based partly on breed characteristics and size. Bigger animals tend to have shorter life spans than smaller ones do. While cats vary little in size, the size and life expectancy of dogs can vary greatly – think a Chihuahua versus a Great Dane.</p>
<p>Human life expectancy has changed over the years. And vets are now able to provide far superior medical care to pets than we could even a decade ago. So now we use a better methodology to define just how old rule of thumb that counted every calendar year as seven “animal years.”</p>
<p>Based on the American Animal Hospital Association <a href="https://doi.org/10.5326/JAAHA-MS-4009">Canine Life Stages Guidelines</a>, today’s vets divide dogs into six categories: puppy, junior, adult, mature, senior and geriatric. Life stages are a more practical way to think about age than assigning a single number; even human health recommendations are based on developmental stage rather than exactly how old you are in years.</p>
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<p>Dog breed and its associated size is one of the largest contributors to life expectancy, with nutrition and associated weight likely being the next most important factors for individual dogs.</p>
<p>But this still doesn’t answer the question of how old your individual animal is. If you’re determined to figure out if Max would be graduating from high school or preparing for retirement based on how many “dog years” he’s lived, these life stages can help. Lining up canine and human developmental milestones over the course of an average life expectancy can provide a rough comparison.</p>
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<p>In a similar manner, the joint American Association of Feline Practitioners-The American Animal Hospital Association <a href="https://www.aaha.org/public_documents/professional/guidelines/felinelifestageguidelines.pdf">Feline Life Stage Guidelines</a> also divide cats into six categories: kitten, junior, prime, mature, senior and geriatric. Since most healthy cats are around the same size, there’s less variability in their age at each life-stage.</p>
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<p>Figuring out how old Buddy is in dog years or Fluffy is in cat years allows a veterinarian to determine their life-stage. And that’s important because it suggests what life-stage-specific health care the animal might need to prolong not just its life, but also its quality of life.</p>
<p>Physicians already apply this very concept to <a href="https://www.hhs.gov/programs/prevention-and-wellness/health-screenings/index.html">human age-specific health screenings</a>. Just like a normal human toddler doesn’t need a colonoscopy, a normal puppy doesn’t need its thyroid levels checked. An adult woman likely needs a regular mammogram, just like an adult cat needs annual intestinal parasite screenings. Of course these guidelines are augmented based on a physician’s or veterinarian’s examination of the human or animal patient.</p>
<p>And as is the case for people, your pet’s overall health status can influence their “real age” for better or for worse. So next time you take your pet to the veterinarian, talk about your animal’s life stage and find out what health recommendations come with it. Watching out for health abnormalities and maintaining a healthy weight could help your cat live long past the literal “prime” of its life.</p><img src="https://counter.theconversation.com/content/98685/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jesse Grady receives funding from The Stanton Foundation. </span></em></p>Based on his age in ‘dog years,’ could your animal pal legally buy alcohol? Or would he be cashing in on his senior discount? Veterinarians are more interested in life stage than a particular number.Jesse Grady, Clinical Instructor of Veterinary Medicine, Mississippi State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/907682018-02-02T13:55:51Z2018-02-02T13:55:51ZHeight, lifespan, GDP: humanity has stagnated for most of its history<figure><img src="https://images.theconversation.com/files/203547/original/file-20180126-100923-184betm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Is the observation that the standard of living stagnated until 1820 reliable?</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/BXOXnQ26B7o">Uroš Jovičić/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Measuring economic growth is difficult, especially for periods for which little information is available. However, harmonized national accounts were set up in most countries after World War II, and they provide different ways to measure aggregate production, either through summing the added values of all resident production sectors, or through summing all the incomes distributed by those sectors. Based on a broad set of historical studies, <a href="http://www.ggdc.net/maddison/oriindex.htm">Maddison (2003)</a> reconstructed income per capita data over the past two centuries, and added some point estimates for earlier periods (in 1 Common Era (CE), 1000 CE, 1500 CE, 1600 CE and 1700 CE). Such estimates often require educated guesses on unobservable trends, but they nonetheless show the best information given what is known at one point in time. </p>
<p>Recently, Bolt and van Zanden, (2013) have revised and complemented Maddison’s work with the <a href="https://www.rug.nl/ggdc/historicaldevelopment/maddison/">“Maddison project”</a>), and some of the findings are striking. </p>
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<p>Over the past millennium, income per capita in the selected countries has increased 32-fold, from 717 US dollars per person per year around the year 1000 to 23,086 dollars in 2010. This contrasts sharply with the previous millennia, when there was almost no advance in income per capita. The figure shows that it started rising and accelerating around the year 1820 and it has sustained a steady rate of increase over the last two centuries. One of the main challenges for growth theory is to understand this transition from stagnation to growth and in particular to identify the main factor(s) that triggered the take-off.</p>
<p>Is the finding that there was stagnation in the standard of living until 1820 truly robust? This claim is particularly important given that mankind experienced significant technological improvements that would have been expected to increase productivity and income per person, from the Neolithic revolution to the invention of the printing press. </p>
<p>Two facts corroborate the idea that there was indeed stagnation over the most part of human history: first, estimates of longevity computed on specific groups across time and space do not display any trend before 1700 CE. For example, <a href="https://link.springer.com/article/10.1007/s10887-015-9117-0">De la Croix and Licandro (2015)</a> show using a long-running database of 300,000 famous people that there was no trend in mortality during most of human history, confirming the existence of a Malthusian stagnation epoch. </p>
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<p>Second, body height computed from skeletal remains does not display any trend either, while height is known to depend very much on nutrition when young <a href="https://www.jstor.org/stable/41378413">(Koepke and Baten, 2005)</a>. This indicates that there was no systematic improvement in nutrition over time. One has to wait until the 19th century to observe a trend in height, as witnessed by the data of the Swedish army. </p>
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<p>The three measures of standard of living proposed here – GDP per capita, height and lifespan – are therefore in the same direction: that of stagnation for most of human history. The economic growth that we now enjoy, with its positive effects on the standard of living but also its negative effects on the environment, is therefore an unprecedented and recent phenomenon on a historical scale.</p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/201397/original/file-20180109-36019-1jllshy.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/201397/original/file-20180109-36019-1jllshy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=244&fit=crop&dpr=1 600w, https://images.theconversation.com/files/201397/original/file-20180109-36019-1jllshy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=244&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/201397/original/file-20180109-36019-1jllshy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=244&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/201397/original/file-20180109-36019-1jllshy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=306&fit=crop&dpr=1 754w, https://images.theconversation.com/files/201397/original/file-20180109-36019-1jllshy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=306&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/201397/original/file-20180109-36019-1jllshy.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=306&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>This article is part of a series of contributions from the <a href="http://www.ipsp.org">International Panel on Social Progress</a>, an international academic initiative bringing together 300 researchers and academics – all social sciences and humanities – who are preparing a report on the prospects for social progress for the 21st century. In partnership with The Conversation France, these articles offer an exclusive overview of the contents of the report and the research of its authors.</em></p>
<p><em>The data visualizations were done by Diane Frances</em>.</p><img src="https://counter.theconversation.com/content/90768/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David de la Croix receives funding from the French speaking community of Belgium (ARC project 15/19-063, "Family Transformations, Incentives and Norms".</span></em></p>Despite the technological advances that humanity has known for millennia, the standard of living did not begin to rise until around 1800.David de la Croix, Professeur d'économie, Université catholique de Louvain (UCLouvain)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/872172017-11-12T23:09:53Z2017-11-12T23:09:53ZLoneliness could kill you<figure><img src="https://images.theconversation.com/files/194015/original/file-20171109-13296-zeo2ob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Studies are showing that loneliness can be deadly, even more so than obesity. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Independence is glorified in North American culture as a symbol of strength. As a society, we value individual achievement and extol self-reliance.</p>
<p>I am an expert on aging and retirement and I also help employees transition from work to retirement by facilitating seminars and workshops in corporate Canada. And I often wonder however if our “go at it alone” attitude has led us down a lonely and isolating path.</p>
<p>Here are some recent stats: </p>
<ul>
<li><p>40 per cent of Americans <a href="https://hbr.org/cover-story/2017/09/work-and-the-loneliness-epidemic">don’t feel close to others</a> at any given time. And the number of lonely Americans has doubled since the 1980s.</p></li>
<li><p><a href="http://www.carp.ca/2017/06/05/loneliness-survey-results/">In a recent Canadian Association of Retired People poll</a>, 16 per cent of Canadians indicated that they lacked companionship</p></li>
<li><p>Fifteen per cent in the CARP poll said they had nobody to turn to or talk to</p></li>
<li><p>Fifteen per cent were unhappy doing things alone.</p></li>
</ul>
<p>I suspect that these numbers are even higher among the general Canadian population, not just CARP members.</p>
<p>According to science, loneliness shortens our lifespan. <a href="https://news.uchicago.edu/article/2014/02/16/aaas-2014-loneliness-major-health-risk-older-adults">Twice as much as obesity.</a> Yes, you read that right.</p>
<p>Dr. John <a href="http://psychology.uchicago.edu/people/faculty/cacioppo/">Cacioppo</a>, the world’s foremost authority on loneliness, maintains that the number of people in your life does not inoculate you from experiencing loneliness. Rather, it’s the feeling of being lonely that places the brain and body at risk.</p>
<p>Cacioppo equates feeling lonely with feeling hungry. We compromise our survival and well-being when either is ignored.</p>
<p>We are biologically hardwired to respond to our environment. When we experience low blood-sugar levels, we crave food. The feeling of our stomachs being empty is a warning sign to eat and it’s essential to our very survival.</p>
<p>When we feel lonely, we desire connection with others, much like the loud rumble that your tummy makes when hungry.</p>
<h2>A lonely brain is restless</h2>
<p>Loneliness triggers “hyper-vigilance.” That is your brain is on the lookout for social threats, which consequently puts us on the defensive. We become more reactive to negative events and perceive daily hassles as more stressful.</p>
<p>A lonely brain awakens often, experiences fragmented sleep and cannot recover from the day’s stressful events.</p>
<p>A lonely brain is also subject to an increase in depressive symptoms and has difficulty self-regulating. That is why you may find yourself irritable and impulsive.</p>
<p>A lonely brain is also at risk of cognitive and physical decline.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/23232034">A three-year Dutch study</a> followed more than 2,000 participants aged 65 to 86. While none of the participants had signs of dementia at the outset of the study, results revealed that those who reported feeling lonely had a 64 per cent increase in the risk of developing dementia.</p>
<p>People also experience an increase in loneliness when they retire from work. That’s why you want <a href="http://rewiretoretire.com/delay-retirement/">to make sure that you’re retiring <em>to</em> something</a>, and that you have friends outside of your place of employment. </p>
<h2>A lonely body</h2>
<p>Loneliness also affects the body. Psychologist <a href="https://irp.nih.gov/pi/stephen-suomi">Stephen Suomi’s</a> research indicates that loneliness distorts the expression of certain genes. An experiment separating newborn primates from their mothers during their first four months of life resulted in the altered development of immunity-related genes that help the body fight viruses.</p>
<p>Social psychologist <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3633610/">Lisa Jaremka’s research</a> indicates that lonely people have higher levels of activated viruses in their system and are at greater risk of suffering from chronic inflammation, which has been linked to Type 2 diabetes, arthritis, heart disease and even suicide.</p>
<p>While obesity increases your odds of an early death by 20 per cent, loneliness increases <a href="https://www.ucsf.edu/news/2012/06/12184/loneliness-linked-serious-health-problems-and-death-among-elderly">your odds by 45 per cent</a>.</p>
<p>What are we to do with an emotional state that is so powerful that it can alter our brains, compromise our physiology and cut short our longevity?</p>
<h2>The antidote to loneliness</h2>
<ol>
<li><p>Seek out connection: We all need a tribe!</p></li>
<li><p>Stop denying and accept “feeling lonely” as simply a craving for connection.</p></li>
<li><p>Acknowledge the consequences of prolonged loneliness. If you ignore hunger, you starve. Same is true of our need for belonging. If you feel lonely, reach out to others.</p></li>
<li><p>Recognize that quality relationships are most effective at feeding this void.</p></li>
</ol>
<p>We are physiologically and psychologically primed for connection.</p>
<p>The next time you feel lonely and out of sorts, acknowledge it as a signal that you are in need of connection and seek out companionship.</p>
<p>Your body and your brain will be thankful that you did, and you may even increase your longevity.</p><img src="https://counter.theconversation.com/content/87217/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gillian Leithman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Loneliness shortens our life spans and some studies suggest it’s even more lethal than obesity. We are physiologically and psychologically primed for connection, so don’t shrug off your loneliness.Gillian Leithman, Assistant Professor of professional business skills and aging, retirement, and knowledge management researcher, Concordia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/835082017-10-16T18:48:50Z2017-10-16T18:48:50ZWe all have to die of something, so why bother being healthy?<figure><img src="https://images.theconversation.com/files/188929/original/file-20171005-9797-qdefs0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We all have to die of something, so why can't I die by delicious donuts?</span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>It’s 6:45 on a cold and rainy Tuesday morning. The alarm blares. As you begin to wake and wonder how it could possibly be morning already, your good intentions dawn on you. It’s run morning – and it’s the last thing you want to do. As you roll over to hit the snooze button, your mind scrambles for a valid excuse.</p>
<p>Why bother trying to be healthy? <em>We all have to die of something, right?</em></p>
<p>In part this is true. Regardless of our discomfort with death, we all have to die sometime, and we all have to die from something. However, this is where the truth ends. </p>
<p>Today in Australia, the <a href="http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/3303.0%7E2015%7EMain%20Features%7EAustralia's%20leading%20causes%20of%20death,%202015%7E3">leading causes of death</a> are mostly preventable – or at least can be significantly delayed. Factors like poor diet and tobacco drive ailments including heart disease, stroke, diabetes (type 2), lung disease and cancers. And when you look more deeply at what ill-health brings, it’s not just death that makes the strongest case for getting out of bed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-the-government-should-tax-unhealthy-foods-and-subsidise-nutritious-ones-72790">Why the government should tax unhealthy foods and subsidise nutritious ones</a>
</strong>
</em>
</p>
<hr>
<h2>You’ll die later</h2>
<p>Sure you have to die of something, but you may not have to die so soon. <a href="http://content.healthaffairs.org/content/early/2017/07/17/hlthaff.2016.1569">Science</a> suggests having a healthier lifestyle even at age 50 is associated with a four to seven year longer life expectancy.</p>
<p>Even <a href="http://www.bmj.com/content/345/bmj.e5568">at older age</a>, improving lifestyle factors can benefit longevity. Avoiding an unhealthy weight, not smoking, maintaining a social network and engaging in leisure activities around age 75 sees a whopping five years added to a woman’s and six years added to a man’s life span.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-australians-die-cause-5-diabetes-57874">How Australians Die: cause #5 – diabetes</a>
</strong>
</em>
</p>
<hr>
<h2>You’ll be healthier, longer</h2>
<p>Trying to be as healthy as you can is not just about adding more years to your life, but adding <em>healthy</em> years, or even decades. Populations who follow healthy forms of behaviour show a <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0081877">60% decline in dementia</a>, in addition to a 70% reduction in type 2 diabetes, heart disease and stroke when compared with unhealthier peers. Studies also find <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0081877">healthier 50 year-olds</a> live longer without disability than those who are overweight or smoke.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188930/original/file-20171005-9767-1ci868b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188930/original/file-20171005-9767-1ci868b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188930/original/file-20171005-9767-1ci868b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188930/original/file-20171005-9767-1ci868b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188930/original/file-20171005-9767-1ci868b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188930/original/file-20171005-9767-1ci868b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188930/original/file-20171005-9767-1ci868b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188930/original/file-20171005-9767-1ci868b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Yes, we all have to die eventually, but we want to be happy, well, independent and pain-free leading up to our deaths.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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</figure>
<p>A significant proportion of octogenarians are also <a href="https://academic.oup.com/biomedgerontology/article/69/6/640/528242/Heterogeneity-in-Healthy-Aging">living healthier</a>, more active lives. This is seen in measures of mobility, self-care, levels of pain and discomfort, and absence of anxiety and depression. But rather than being related just to age, variations in health-related quality of life are also linked to factors such as exercise, nutrition and social engagement. </p>
<p>So being active and eating well could mean a healthier, more independent life for longer.</p>
<h2>You’ll feel better in the meantime</h2>
<p>Eating healthier and exercising have also been shown to have benefits on your day-to-day wellbeing. Exercise can improve and protect mental health. As a strategy to manage mild to moderate depression, exercise can provide <a href="https://www.ncbi.nlm.nih.gov/pubmed/21495519">comparable benefits to some antidepressants</a>, and can complement medications to improve symptoms further. Similarly, exercise can play a role in treating <a href="https://www.ncbi.nlm.nih.gov/pubmed/23300122">anxiety</a>, obsessive-compulsive disorder, and post-traumatic stress disorder. It can also improve your <a href="https://www.ncbi.nlm.nih.gov/pubmed/28919335">sleep quality</a> and even benefit <a href="https://www.ncbi.nlm.nih.gov/pubmed/25226604">self-esteem</a> and confidence.</p>
<p>It’s thought exercise does this by reducing your sensitivity to the symptoms of anxiety, building resilience to stressful mood states, positively altering the neurotransmitters in the brain, and disrupting or distracting you from social isolation. </p>
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Read more:
<a href="https://theconversation.com/interactive-body-map-physical-inactivity-and-the-risks-to-your-health-68157">Interactive body map: physical inactivity and the risks to your health</a>
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<p>Getting active can also allay general body aches and pains. An <a href="https://www.nature.com/articles/srep45975">Australian study</a> recently suggested jogging improves the composition of the cushion-like discs in your spine, reducing wear and tear. Exercise not only fortifies the discs but is also <a href="https://www.ncbi.nlm.nih.gov/pubmed/18801686">generally effective</a> in preventing and treating pain. This is particularly important given <a href="http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/4841.0Chapter12011">67% of Australians</a> experience pain at least monthly, with inactivity being a major risk factor.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188931/original/file-20171005-9767-1m6e88v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188931/original/file-20171005-9767-1m6e88v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188931/original/file-20171005-9767-1m6e88v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188931/original/file-20171005-9767-1m6e88v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188931/original/file-20171005-9767-1m6e88v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188931/original/file-20171005-9767-1m6e88v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188931/original/file-20171005-9767-1m6e88v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188931/original/file-20171005-9767-1m6e88v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Exercise has benefits for most aspects of our physical and mental well-being.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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<p>A healthy diet combined with exercise can also <a href="https://www.ncbi.nlm.nih.gov/pubmed/25963237">strengthen your bones</a>, reducing the risk of fractures if you do have a serious injury.</p>
<h2>You’ll save more and spend less</h2>
<p>There’s <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-016-2996-y">good evidence</a>, including <a href="https://theconversation.com/a-healthy-diet-is-cheaper-than-junk-food-but-a-good-diet-is-still-too-expensive-for-some-57873">from Australia</a>, that eating healthy food is actually more affordable than an unhealthy diet. And smoking one pack of cigarettes per day, when combined with the health costs that result, is estimated to cost a staggering <a href="https://www.cancer.org/research/infographics-gallery/tobacco-related-healthcare-costs.html">US$638,750</a> (A$812,556) to you and society over 50 years.</p>
<p>Type 2 diabetes, often associated with obesity, is estimated to result in A$4,025 per year per person in <a href="https://static.diabetesaustralia.com.au/s/fileassets/diabetes-australia/e7282521-472b-4313-b18e-be84c3d5d907.pdf">total costs</a> without medical complications, or in excess of A$9,645 once complications develop. These costs are incurred not only through the need for treatment, but also in job discrimination, higher health insurance costs, lost productivity with sick days and poor physical function.</p>
<p>While no similar analysis exists for Australia, evidence from the US estimates lifetime social and public health costs of obesity at <a href="http://www.thefiscaltimes.com/2015/05/15/New-Lifetime-Estimate-Obesity-Costs-92235-person">US$92,235</a> (A$117,332) per person, when combining medical expenditure and reduced productivity. </p>
<p>The <a href="https://www.pwc.com.au/pdf/weighing-the-cost-of-obesity-final.pdf">direct medical costs</a> to individuals in Australia may be lower due to our universal health system, but the costs from obesity still add up to A$873 million each year. A <a href="http://www.medibank.com.au/client/documents/pdfs/the_cost_of_physical_inactivity_08.pdf">A$719 million per annum</a> slice of the Australian budget is spent on the complications of physical inactivity alone, through heart disease, stroke, type 2 diabetes, breast cancer, colon cancer, depression and falls.</p>
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<strong>
Read more:
<a href="https://theconversation.com/sugar-tax-is-not-nanny-state-its-sound-public-policy-59059">Sugar tax is not nanny state, it's sound public policy</a>
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<p>This isn’t noted to shame anyone or to recommend reducing care, it’s about realising policy and health inaction comes at a huge economic and social cost.</p>
<h2>Your kids will be healthier, and maybe even their kids</h2>
<p>Poor diet, smoking, alcohol use and a lack of physical activity can also affect your kids’ health – and maybe even the health of their kids.</p>
<p>Firstly, through role modelling. The kids of parents <a href="http://www.medicaldaily.com/role-models-kids-are-6-times-more-likely-smoke-if-older-siblings-or-parents-smoke-249207">who smoke</a> are <a href="https://link.springer.com/article/10.1007/s10865-006-9090-3">significantly</a> more likely to smoke themselves, and likewise with <a href="https://drinkwise.org.au/parents/is-your-drinking-influencing-your-kids/#">unhealthy drinking</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/22089441">eating</a>. These kids are <a href="https://www.ncbi.nlm.nih.gov/pubmed/16391557">also more likely</a> to be obese. Some of these effects could also be from socioeconomic factors.</p>
<p>Second, through a mechanism called <a href="https://theconversation.com/how-epigenetics-may-help-us-slow-down-the-ageing-clock-76878">epigenetics</a>, our own health can influence the health of subsequent generations. This results from alterations in the expression of genes and not through changes in the genes themselves. </p>
<p>Altered epigenetics from physical inactivity, diet and environmental factors are <a href="https://theconversation.com/how-your-grandparents-life-could-have-changed-your-genes-19136">now thought to be</a> <a href="https://www.ncbi.nlm.nih.gov/pubmed/25253098">passed down</a> through generations. They influence the subsequent risk of metabolic diseases such as obesity and diabetes.</p>
<p>Finally, being overweight, a <a href="http://www.mayoclinic.org/diseases-conditions/infertility/symptoms-causes/dxc-20228738">lack of exercise</a> and even <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3321066/">consuming sugary drinks</a> could actually reduce your chances of having kids in the first place. In women, being overweight increases the risk of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861983/">polycystic ovarian syndrome</a>, which causes irregular ovulation and can occasionally render women infertile.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/walking-the-fine-line-between-healthy-weight-advice-and-fat-shaming-81759">Walking the fine line between healthy weight advice and fat shaming</a>
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<p>While in men, excess weight contributes to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408383/">infertility</a> by reducing the quality of semen, as well as increasing the risks of sexual dysfunction. </p>
<h2>The bigger picture</h2>
<p>Living a healthier lifestyle is about making small, possible, simple and sustainable changes like taking the stairs instead of the lift - not totally rethinking the way you live. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/189038/original/file-20171005-9753-kigbq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/189038/original/file-20171005-9753-kigbq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/189038/original/file-20171005-9753-kigbq2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/189038/original/file-20171005-9753-kigbq2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/189038/original/file-20171005-9753-kigbq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/189038/original/file-20171005-9753-kigbq2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/189038/original/file-20171005-9753-kigbq2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Being healthy is about small, incremental, sustainable changes over many years.</span>
<span class="attribution"><span class="source">Flickr / TYFVMP</span></span>
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<p>But while there are many compelling reasons to be healthy, personal discipline alone will never solve our chronic disease and obesity epidemics. If neighbourhoods lack safe spaces for kids to run, or fresh food is inaccessible and unaffordable, good intentions will not get you very far. Government policies need to make health easier, even preferred.</p>
<p>In the meantime, look to friends for motivation; your family to share and support a healthy diet; <a href="https://www.vichealth.vic.gov.au/media-and-resources/vichealth-apps/healthy-living-apps">apps</a> that map and commend the exercise you do; and your GP and important services like <a href="http://www.quitnow.gov.au/">Quitline</a> for assistance with alcohol reduction and smoking cessation.</p><img src="https://counter.theconversation.com/content/83508/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Alessandro Demaio works for the World Health Organization in Geneva. This post was written by Dr Alessandro Demaio in his personal capacity. The views, opinions and positions expressed in this article are the author’s own and do not reflect the views of any third party. Additionally, those providing comments on this blogs are doing so in their personal capacity, and do not necessarily reflect the views, opinions or positions of the author.
Sandro is also co-host of ABC TV's Ask The Doctor.</span></em></p>Sure, you have to die of something, but you may not have to die so soon - and you could be healthier, wealthier and happier in the meantime.Sandro Demaio, Australian Medical Doctor; Fellow in Global Health & NCDs, University of CopenhagenLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/834852017-09-18T02:28:18Z2017-09-18T02:28:18ZI’ve always wondered: does anyone my age have any chance of living for centuries?<figure><img src="https://images.theconversation.com/files/184593/original/file-20170905-9762-kpxfwo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How likely is it that someone alive today may live for centuries?</span> <span class="attribution"><span class="source">Flickr/Santiago Sito</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><em>This is an article from I’ve Always Wondered, a new series where readers send in questions they’d like an expert to answer. Send your question to alwayswondered@theconversation.edu.au</em></p>
<hr>
<p><strong>Does anyone my age have any chance of living for centuries? Will younger generations have a chance? - Adam Barclay, 44, Newcastle.</strong></p>
<p>One century? Yes, a decent chance. We might in theory be able to live for centuries. This is a dream that many are working towards - but we aren’t there yet.</p>
<p>The subject of living longer, and more importantly, healthier lives is now a <a href="https://theconversation.com/the-search-to-extend-lifespan-is-gaining-ground-but-can-we-truly-reverse-the-biology-of-ageing-75127">serious, mainstream endeavour in biology and medical science</a>. </p>
<p>Molecular biologists, geneticists, and nutritional scientists are reaching for the ultimate goal of delaying onset of age-related conditions, which would reduce the incidence of nearly every non-communicable disease ageing brings. </p>
<p>Although reduced disease burden is the public health goal that motivates governments and the medical science community to pursue ageing research, it is living longer - finding the elixir of youth, seeking immortality - that captures the public imagination.</p>
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Read more:
<a href="https://theconversation.com/the-search-to-extend-lifespan-is-gaining-ground-but-can-we-truly-reverse-the-biology-of-ageing-75127">The search to extend lifespan is gaining ground, but can we truly reverse the biology of ageing?</a>
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<p>With the exception of wars, famine, or <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4679063/">major economic dislocation</a>, human lifespan has been steadily increasing around the world for the past century. Life expectancy in Australia is around 83 years, the <a href="http://www.who.int/gho/publications/world_health_statistics/2016/Annex_B/en/">fourth greatest in the world</a>. These gains are largely due to improved access to and quality of health care. We are yet to see the impact of therapies specifically targeted to treat ageing, which could turbo-charge this increase in life expectancy.</p>
<h2>What researchers are working on</h2>
<p>Most of the anti-ageing or “geroprotective” compounds under development work by mimicking the effects of calorie restriction or physical exercise. Lifelong calorie restriction, reducing calorie intakes by around 30%, is one of the <a href="https://www.ncbi.nlm.nih.gov/pubmed/12936916">strongest interventions known for extending lifespan</a>. </p>
<p>For the past two decades, research into ageing has sought to determine which genes and molecular pathways are turned on and off by eating less and exercising more. This has resulted in the discovery of a number of pathways (called the <a href="https://www.ncbi.nlm.nih.gov/pubmed/27552971">sirtuins</a>, <a href="https://www.nature.com/nature/journal/v424/n6946/full/nature01789.html">insulin/IGF-I signalling</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/23325216">mTOR</a>, and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4287273/">AMPK</a>) that can be manipulated in animals to extend lifespan. An anti-diabetic drug called metformin activates one of these, and is <a href="https://www.ncbi.nlm.nih.gov/pubmed/27304507">being trialled to improve health in old age</a>.</p>
<p>Another way to extend lifespan might be to remove so-called “<a href="http://www.nature.com/nrm/journal/v15/n7/abs/nrm3823.html">senescent</a>”, or old and damaged cells, which <a href="https://www.ncbi.nlm.nih.gov/pubmed/26840489">cause disease</a>. But here’s the thing - those pathways extend lifespan by only up to 30%, which on a “normal” human lifespan of 83 years, takes us to merely one century. </p>
<p>While increasing life expectancy to over a century would be an <em>astounding</em> achievement, this is nowhere near the centuries that many people dream of. To achieve that, the biology of ageing will have to move beyond mimicking calorie restriction, tinkering with metabolism, and trimming away old cells. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/185624/original/file-20170912-11499-p60yex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185624/original/file-20170912-11499-p60yex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185624/original/file-20170912-11499-p60yex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185624/original/file-20170912-11499-p60yex.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185624/original/file-20170912-11499-p60yex.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185624/original/file-20170912-11499-p60yex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185624/original/file-20170912-11499-p60yex.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185624/original/file-20170912-11499-p60yex.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Calorie restriction is one of the most reliable ways to extend lifespan.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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<h2>Possible future directions</h2>
<p>Instead, we might look to nature for inspiration. The jellyfish <a href="https://www.ncbi.nlm.nih.gov/pubmed/9615920?dopt=Abstract"><em>Hydra</em> has no discernable biological ageing</a>, and is functionally immortal, most likely due to a <a href="https://www.ncbi.nlm.nih.gov/pubmed/19891641">high content of stem cells</a> that can replenish the adult body. Another species, <em>Turritopsis dohrnii</em>, the “immortal jellyfish”, can <a href="http://www.journals.uchicago.edu/doi/abs/10.2307/1543022">reverse back from its adult body into its juvenile state</a>, as a polyp growing on a rock, and then grow back into an adult, and repeat that cycle to achieve near immortality. </p>
<p>So how could we imitate the immortal jellyfish? Well, we could reprogram our “epigenomes” - which is the arrangement that keeps different parts of our DNA code turned on and off. Excitingly, we already know how to do this. There are just four genes, called “Yamanaka factors”, which <a href="https://www.ncbi.nlm.nih.gov/pubmed/18035408">rejuvenate adult cells back into embryonic stem cells</a> - like Benjamin Button, this would mean turning our cells from aged adults back to those of a developing baby.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/why-we-cant-live-forever-understanding-the-mechanisms-of-ageing-7353">Why we can't live forever: understanding the mechanisms of ageing </a>
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<p>In theory, turning these factors on for the right amount of time in the right places could rejuvenate our bodies back into those of young people - at which point, in theory, we <em>might</em> be able to live for centuries. </p>
<p>The trick will be figuring out when, where, how much and for how long to turn these Yamanaka factors on. <a href="https://www.nature.com/nature/journal/v502/n7471/full/nature12586.html">Too much</a>, and our organs could turn into a mass of undifferentiated embryonic stem cells, which could grow back into the wrong tissue type. Too little, and there would be no effect. Getting the <a href="https://www.ncbi.nlm.nih.gov/pubmed/27984723">dosage <em>just right</em></a> could be very powerful. Testing for the first time in humans would be risky. </p>
<p>It’s worth remembering that extending lifespan alone is not the same as extending quality of life or healthy years. Advancement of lifespan should not occur by delaying death following long periods of sickness. Instead, <a href="https://www.ncbi.nlm.nih.gov/pubmed/7383070">shortening the amount of time people are unwell</a> should be the ultimate goal. </p>
<p>At some point prior to death, everyone crosses the threshold of being independent, healthy and active, to becoming dependent, sick and immobile. The duration spent below this threshold is unique to the individual, but everyone agrees this time should be minimal in comparison to the person’s healthy years. </p>
<p>Lifestyle changes, and advances in technology and medicine, aim to maximise the proportion of time spent living life to the fullest and delaying the (unavoidable) onset of age-related conditions. But living for centuries remains a dream – for now.</p>
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<p><em>* Email your question to alwayswondered@theconversation.edu.au
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* Tell us on <a href="http://www.facebook.com/conversationEDU">Facebook</a></em></p><img src="https://counter.theconversation.com/content/83485/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lindsay Wu is a founder, director and shareholder in Jumpstart Fertility and Life Biosciences. He is also a shareholder in Continuum Biosciences, Senolytic Therapeutics, EdenRoc Sciences, and Intravital. His lab at UNSW Sydney receive funding from the National Health and Medical Research Council (NHMRC) of Australia and Jumpstart Fertility, and has in the past received funding from Cancer Institute NSW and MetroBiotech NSW. His salary at UNSW Sydney is supported by an RD Wright Biomedical Fellowship from the NHMRC. </span></em></p><p class="fine-print"><em><span>Stefanie Mikolaizak works at Robert Bosch Krankenhaus (Hospital) in Germany. RBMF is the medical research department associated with the hospital of the German charity foundation “Robert Bosch Stiftung”. She is currently coordinating the German clinical site of a large multi-centre intervention trial (PreventIT). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 689238.</span></em></p>Reader Adam Barclay, 44, wants to know if someone his age has any chance of living forever.Lindsay Wu, NHMRC Senior Lecturer, School of Medical Sciences, UNSW SydneyStefanie Mikolaizak, Postdoc Fellow, Robert Bosch KrankenhausLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/752062017-04-03T19:22:49Z2017-04-03T19:22:49ZHealth-care spending has only a modest effect on lifespan and premature death<figure><img src="https://images.theconversation.com/files/163260/original/image-20170330-15595-y9p3he.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A new analysis found spending on health doesn't have a big effect on whether people die prematurely. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><a href="http://www.sciencedirect.com/science/article/pii/S0277953617301132">A new analysis has found</a> spending more on health care has little impact on improving key health outcomes. It found that a 10% increase in health-care spending reduces the number of deaths by only 1.3%, and increases life expectancy by only 0.4%. </p>
<p>Our new meta-analysis, which pooled results from 65 studies, looked at health-care spending by both the private and public sectors including preventive and curative care.</p>
<p>Health-care spending as a share of GDP has nearly doubled in <a href="http://www.oecd.org/els/health-systems/health-data.htm">OECD countries</a> since 1970. Death rates fell in OECD countries by 86% during this period. While this is a great achievement, given our study found health spending improves death rates by only a small amount, the doubling of spending explains only a small fraction of this large improvement in health. This is because health-care spending is only one of many factors that affect health. </p>
<p>Our analysis looked at two measures of health: life expectancy and death rates, which are major health status indicators. These are two of the most important measures of health status, but health care treats a large number of diseases and conditions not investigated by our study.</p>
<p>Our analysis also showed public health-care spending is more effective in reducing death than private spending, contrary to <a href="http://www.tandfonline.com/doi/abs/10.1080/00036840210135665?journalCode=raec20">some earlier studies</a>. We found no real difference between the effect of spending on health in developed and developing countries, or between genders.</p>
<h2>Wealthier countries spend more on health</h2>
<p>Health-care spending per person has risen throughout the world. In 2014, the high-income OECD countries spent, on average, the equivalent of <a href="http://api.worldbank.org/v2/en/indicator/SH.XPD.PCAP.PP.KD?downloadformat=excel">US$4,698</a> per person on health. In Australia we spent US$4,357 per person. These amounts are significantly higher than the global average of US$1,276 per person. </p>
<p>Over time, spending on health has been diverging between high-income countries and the rest of the world, with spending in high-income countries growing faster than in other countries. This raises the issue of value for money, especially in the USA where spending is US$9,403 per person. This is despite having pretty <a href="https://ourworldindata.org/the-link-between-life-expectancy-and-health-spending-us-focus">poor outcomes</a> compared to money spent.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/163570/original/image-20170403-19445-1y6tfpc.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/163570/original/image-20170403-19445-1y6tfpc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/163570/original/image-20170403-19445-1y6tfpc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163570/original/image-20170403-19445-1y6tfpc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163570/original/image-20170403-19445-1y6tfpc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163570/original/image-20170403-19445-1y6tfpc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163570/original/image-20170403-19445-1y6tfpc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163570/original/image-20170403-19445-1y6tfpc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Richer countries spend more on health care. Data here are in international dollars, adjusted for inflation and purchasing power price differences.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Even though spending is diverging among countries, some health outcomes are becoming similar over time between developed and developing countries. For example, child mortality has fallen throughout the world but the fall has been greater in non-OECD countries.</p>
<p>In 1960, <a href="http://api.worldbank.org/v2/en/indicator/SH.DYN.MORT?downloadformat=excel">child mortality</a> in OECD countries was 63 deaths per 1,000, compared to 183 in the world as a whole. This is a difference of 120 deaths. By 2015, mortality in the OECD countries fell to seven deaths per 1,000 and in the world as whole mortality fell to 43.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/163571/original/image-20170403-19417-8577zq.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/163571/original/image-20170403-19417-8577zq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/163571/original/image-20170403-19417-8577zq.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163571/original/image-20170403-19417-8577zq.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163571/original/image-20170403-19417-8577zq.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163571/original/image-20170403-19417-8577zq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163571/original/image-20170403-19417-8577zq.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163571/original/image-20170403-19417-8577zq.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The gap in child mortality between the OECD and all nations is narrowing.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>And while <a href="http://api.worldbank.org/v2/en/indicator/SP.DYN.LE00.IN?downloadformat=excel">life expectancy</a> has increased globally, the gap between OECD countries and all countries has remained largely unchanged.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/163572/original/image-20170403-19452-8lfw16.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/163572/original/image-20170403-19452-8lfw16.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/163572/original/image-20170403-19452-8lfw16.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163572/original/image-20170403-19452-8lfw16.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163572/original/image-20170403-19452-8lfw16.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163572/original/image-20170403-19452-8lfw16.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163572/original/image-20170403-19452-8lfw16.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163572/original/image-20170403-19452-8lfw16.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Life expectancy has increased globally but a large gap remains between nations.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>So where should the money go?</h2>
<p>So it follows from our study that household income, education, wealth inequality, demographics and lifestyle choices play a collectively more important role in improving health. Lifestyle choices include nutrition, physical activity, and the consumption of alcohol and tobacco. </p>
<p>Some health-care spending is <a href="http://www.keepeek.com/Digital-Asset-Management/oecd/social-issues-migration-health/tackling-wasteful-spending-on-health_9789264266414-en#page1">wasted</a> on <a href="https://theconversation.com/why-were-wasting-money-on-medical-tests-and-how-behavioural-insights-can-help-72801">unnecessary procedures</a>, <a href="https://theconversation.com/how-to-slash-half-a-billion-dollars-a-year-from-australias-drugs-bill-73050">slow uptake of generic drugs</a> and administrative inefficiencies. Some of this is possibly due to the influence of powerful interest groups such as the pharmaceutical industry and medical bureaucracies.</p>
<p>The finding that public funding of health care results in a slightly larger reduction in premature death than private funding highlights the importance of directing funding to government hospitals and other public health measures. Progress in medical technology – for example, in fighting cancer and heart disease – is especially important and warrants additional funding.</p><img src="https://counter.theconversation.com/content/75206/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Doucouliagos does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Our new meta-analysis, which pooled results from 65 studies, looked at health-care spending by both the private and public sectors including preventive and curative care.Chris Doucouliagos, Professor of Economics, Department of Economics, Deakin Business School and Alfred Deakin Institute for Citizenship and Globalisation, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/668522016-10-12T05:31:18Z2016-10-12T05:31:18ZIf we were like mice we could live to 400 – but we’re not, so we don’t<figure><img src="https://images.theconversation.com/files/141351/original/image-20161012-8418-1x6rscg.jpg?ixlib=rb-1.1.0&rect=8%2C116%2C2959%2C2241&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mice can slow the wheel of ageing almost at will. Humans, not so much.</span> <span class="attribution"><span class="source">Ron and Joe/Shutterstock.com</span></span></figcaption></figure><p>You may have seen the news that the human lifespan <a href="https://theconversation.com/is-there-a-natural-limit-to-how-long-humans-can-live-66460">cannot be extended beyond about 115 years</a>, as shown by a <a href="http://www.nature.com/nature/journal/vaop/ncurrent/full/nature19793.html">demographic analysis</a> confirming that the steady improvements in lifespan seen for many populations over recent decades has stalled since the 1990s.</p>
<p>The researchers’ conclusion that “the maximum lifespan of humans is fixed and subject to natural constraints” is sobering reading for those who dream that human ageing can one day be successfully hacked. But for evolutionary ecologists, it should not come as a surprise.</p>
<p>As well as striking a note of biological realism, this research also highlights how research on human ageing often neglects the insights available from evolutionary theory – and particularly from a research field called “comparative life-history ecology”. </p>
<p>This genre of research explains why mice and humans grow old at such different rates (more on why this is a problem for ageing research later). It aims to bring us closer to understanding the “ultimate” reasons why we age – which in turn can tell us whether the hundreds of millions of dollars poured into ageing research are actually a good investment. </p>
<p>Strive as we might, an evolutionary perspective tells us that maximum lifespans will not be extended by simply solving one symptom of ageing after another.</p>
<h2>Growing old – the ‘why’ as well as the ‘how’</h2>
<p>Ageing – or “senescence”, to use the biological term – is defined as a decline in physiological condition with age. You might wonder why natural selection allows this to happen at all. The answer is that senescence happens in a “selection shadow” – that is, after organisms have already reproduced and passed on their genes. There is no real evolutionary penalty for failing to ward off the ravages of old age, because in animal populations relatively few individuals make it into their geriatric years anyway, thanks to predators, disease, hardship or bad luck.</p>
<p>Natural selection reaches a crescendo at sexual maturity, when most individuals in a population are alive and striving to produce viable offspring. This is the age at which the genetic baton is passed to the next generation. Unfortunately for those of us over 40, it’s all downhill from here in terms of the evolutionary pressure to maintain a healthy body.</p>
<p>This knowledge – that selection pressure changes with age in a way that depends not just on the expected lifespan but also on the timing of reproductive effort – is fundamental to evolutionary theories of ageing. It is also fundamental to how we design and interpret the research that aims to help us prolong our own maximum lifespans.</p>
<p>Many of the species most frequently studied by biologists – such as mice, flies and worms – are chosen precisely because their short lifespans and fast generational turnover make them quicker and easier to work with. But their short lives and adaptable reproductive strategies actually make them unsuitable models for testing drugs or other anti-ageing interventions aimed at slowing human ageing.</p>
<p>Short-lived species seem to be able to “trade in” their investment in growth and sexual reproduction in return for slowing down the ageing process – <a href="http://rspb.royalsocietypublishing.org/content/282/1806/20150209">switching to a physiological state</a> in which they instead invest in maintenance of body condition and warding off senescence. </p>
<p>This strategy makes sense for species whose brief lives can be subject to wide variability in environmental conditions. For a small rodent, having a litter of pups would be rather pointless if food is too scarce for them to grow and survive to adulthood. Hamsters, for example, can instead enter a torpid state that actually <a href="http://rsbl.royalsocietypublishing.org/content/8/2/304">protects their cells from ageing</a> over winter.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/141349/original/image-20161012-8401-tvejbw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/141349/original/image-20161012-8401-tvejbw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/141349/original/image-20161012-8401-tvejbw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/141349/original/image-20161012-8401-tvejbw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/141349/original/image-20161012-8401-tvejbw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/141349/original/image-20161012-8401-tvejbw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/141349/original/image-20161012-8401-tvejbw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/141349/original/image-20161012-8401-tvejbw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For mice, having babies really can age you faster.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File%3ABabymouse.jpg">ShwSie/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>In contrast, species with long expected natural lifespans (which have reduced their mortality risk by evolving to a large size, or being able to fly or hibernate, or having a large brain) have already invested strongly, and perhaps maximally, in protecting their cells from ageing. This suggests there is no “anti-ageing switch” available to flick for a species such as ourselves. Whether or not we have children, it seems we’re already naturally geared to live as long as we possibly can.</p>
<p>This might sound weird, but it’s supported by a <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0012019">simple comparative analysis</a> that a colleague and I published back in 2010, in which we compared the <em>average expected</em> lifespan with the <em>maximum recorded</em> lifespan for various mammals. From this we can calculate a simple ratio of average to maximum lifespan, which tells you, for a given species, how much it is theoretically possible to expand lifespan.</p>
<p>If we take the ratio of a short-lived species like a mouse and apply it to humans, we would predict a maximum lifespan of about 400 years! But despite all of our efforts to push the boundaries through medicine and nutrition, humans (along with elephants and other highly durable animals) don’t come close to these biblical lifespans.</p>
<p>So if mice find it much easier to slow down the ageing process than we do, what does that mean for anti-ageing studies using mice? Sadly, the implication is that most tactics shown to prolong lifespan in mice – such as calorie restriction – will be <a href="http://www.nature.com/nature/journal/v489/n7415/full/nature11432.html">far less effective in humans</a>. </p>
<p>If we are to break the evolutionary constraints on maximum lifespan in humans, we need to better take account of life-history ecology. This theory tells us that the causes of ageing are to be found not at the end of our lives, but at the beginning. </p>
<p>How our maximum lifespan is ultimately limited will be understood by research that seeks to answer why the pace of life varies so much among different animals. For me, this is the take-home message from this recent excellent research.</p><img src="https://counter.theconversation.com/content/66852/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Turbill's research has been funded by a Discovery Early Career Researcher Award (DECRA) from the Australian Government.</span></em></p>Anti-ageing research often uses short-lived model species such as mice. But these species age in a very different way to us, so they may not tell us all that much about boosting our own lifespans.Christopher Turbill, Senior Lecturer in Animal Ecology, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/638372016-08-15T18:10:25Z2016-08-15T18:10:25ZHow your parent’s lifespan affects your health<figure><img src="https://images.theconversation.com/files/134086/original/image-20160815-15261-te69mp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A tale of generations.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic.mhtml?language=en&id=284570273">Shutterstock</a></span></figcaption></figure><p>The longer your parents live, the more likely you are to live longer and have a healthy heart. These are the results of <a href="http://dx.doi.org/10.1016/j.jacc.2016.05.072">our latest study</a> of nearly 200,000 volunteers. </p>
<p>The role of genetics in determining the age at which we die is increasingly known, but the relationship between parental age at death and survival and health in their offspring is complex, with many factors playing a part. Shared environment and lifestyle choices also play a large role, including diet and smoking habits, for example. But, even accounting for these factors, parents lifespan is still predictive in their offspring – something we have also <a href="http://dx.doi.org/10.1093/gerona/glt061">shown in previous research</a>. However it was unclear how the health advantages of having longer-lived parents was transferred to children in middle age. </p>
<p>In the new study, published in the Journal of the American College of Cardiology, we used information on people in the <a href="http://www.ukbiobank.ac.uk/">UK Biobank study</a>. The participants, aged 55 to 73, were followed for eight years using data from hospital records. We found that for each parent that lived beyond their seventies, the participants had 20% less chance of dying from heart disease. To put this another way, in a group of 1,000 people whose fathers died at 70 and who were followed for ten years, around 50 on average would die from heart disease. But when compared to a group whose fathers died at 80, on average only 40 would die from heart disease over the same ten-year period. Similar trends were seen when it came to the age of mothers. </p>
<p>Interestingly, family history of early heart attacks is already used by physicians to identify patients at increased risk of disease. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/134088/original/image-20160815-15256-1h069bs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/134088/original/image-20160815-15256-1h069bs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/134088/original/image-20160815-15256-1h069bs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/134088/original/image-20160815-15256-1h069bs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/134088/original/image-20160815-15256-1h069bs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/134088/original/image-20160815-15256-1h069bs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/134088/original/image-20160815-15256-1h069bs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Family history?</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-109674029/stock-photo-adult-man-suffering-from-severe-heartache.html?src=E1az-Yn7oCNyMZ1az83bGg-1-16">Shutterstock</a></span>
</figcaption>
</figure>
<h2>All is not lost</h2>
<p>The biggest genetic effects on lifespan in <a href="http://dx.doi.org/10.18632/aging.100930">our studies</a> affected the participant’s blood pressure, their cholesterol levels, their body mass index and their likelihood to be addicted to tobacco. These are all factors that affect risk of heart disease, so is consistent with the lower rates of heart disease that we saw in the offspring. We did find some clues in our analysis of novel genetic variants that there might also be other pathways to longer life, for example through better repair of damage to DNA, but much more work is needed on these. </p>
<p>It is really important to note that our findings were group-level effects. These effects do not necessarily apply to individuals, as so many factors affect one’s health. So the results are really positive – although people with longer-lived parents are more likely to live longer themselves, but they do not mean people with shorter-lived parents should lose hope. There are lots of ways for those with shorter-lived parents to improve their health. </p>
<p>Current public health advice about being physically active (for example going for regular walks), eating well and not smoking are very relevant – and people can really take their health into their own hands. People can overcome their increased risk by choosing the healthy options in terms of not smoking, keeping active, avoiding obesity and so on and getting their blood pressures and cholesterol levels tested. Of course, they should discuss their family history with their physicians, as there are some good treatments for some of the causes of premature deaths. </p>
<p>Conversely, people with long-lived parents cannot assume they will therefore live long lives – if you are exposed to the big health risk factors, this will be more important to your health than the age at which your parents died.</p><img src="https://counter.theconversation.com/content/63837/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Pilling receives funding from the University of Exeter.</span></em></p><p class="fine-print"><em><span>Janice Atkins receives funding from the Medical Research Council. </span></em></p>Longer-lived parents have healthier children - but why? Insights from the UK Biobank study.Luke Pilling, Research Fellow in Genomic Epidemiology, University of ExeterJanice Atkins, Research Fellow, University of ExeterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/637412016-08-15T10:46:19Z2016-08-15T10:46:19ZHow old church records are helping us to assess the impact of childhood disease and why we’re living longer<figure><img src="https://images.theconversation.com/files/133811/original/image-20160811-28149-kf0gdz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Finnish family, pictured around the late 19th century.
</span> <span class="attribution"><span class="source">Virpi Lummaa</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The Great Exhibition of 1851, housed in London’s Crystal Palace, showcased the newest of culture and science – including the world’s largest diamond, a precursor to the fax machine and barometer which worked entirely through leeches. Living conditions were tough, but having survived to the age of 20, a young Londoner attending the exhibition could expect to live until around 60. A century and a half later, 20-year-old Londoners watching the Olympics down the pub can expect to live to the age of 80. </p>
<p>But what is behind this extraordinary 50% increase in human lifespan since the 1850s? Many factors are at play, including the development of contraception, vaccination, antibiotics and improved nutrition and hygiene. But the impact of each factor has remained a bit of a mystery. This is a shame, as understanding the precise nature of forces behind lifespan is essential if we want to be able to predict how long we may live in the future. To shed some light on this, <a href="http://www.pnas.org/content/113/32/8951.abstract">we investigated church records</a> from Finnish individuals born between 1751 and 1850, just before this huge extension in lifespan, to work out how childhood diseases may affect a population’s lifespan.</p>
<p>As long ago as 1934, <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2170911/pdf/jhyg00241-0003.pdf">a study</a> reported that a person’s chances of dying were determined not by the current year, but by the year in which they were born. The authors of this early study concluded that “the figures behave as if the expectation of life was determined by the conditions which existed during the child’s earlier years”. So what might these conditions be? </p>
<p>In 2004 <a href="http://science.sciencemag.org/content/305/5691/1736">a new paper</a> put forward a compelling hypothesis to explain the link between early-life conditions and adult mortality. Infectious diseases are caused by bacteria and viruses, which elicit inflammatory immune responses. Many, or severe, infections can lead to chronic inflammation, which is linked to atherosclerosis, a hardening of the arteries, and thrombosis, coagulation of the blood, which are risk factors for cardiovascular disease and stroke. Since 1850, serious childhood infections such as smallpox and whooping cough have largely been eradicated by vaccination and hygiene in industrialised countries.</p>
<p>A decline in serious childhood infections could therefore explain why lifespan has increased: fewer chronic infections, lower inflammation, and less atherosclerosis could have lead to a later onset of cardiovascular disease and therefore longer lifespan. </p>
<p>There is evidence that chronic infections in early life can have a long-lasting impact on inflammation. Union Army soldiers who suffered tuberculosis as young adults during the American Civil War <a href="http://link.springer.com/article/10.2307/2648096">had a 20% increase in risk of cardiovascular disease in middle age</a>. Meanwhile, Tsimane forager farmers in the Bolivian Amazon who live with endemic parasite infections from early life have <a href="http://biomedgerontology.oxfordjournals.org/content/63/2/196.long">far higher levels of inflammation</a> than people in the modern US. Despite this link, higher inflammation in the Tsimane does not lead to cardiovascular disease: they are protected by their excellent diet and active lifestyle. This suggests that such diseases are a result of modern lifestyles and may have been rare during human history. </p>
<p>But this is not the whole story. Intriguingly, people in the Ecuadorian Amazon, who also live with endemic infections, <a href="http://onlinelibrary.wiley.com/doi/10.1002/ajhb.22296/abstract">seem to have lower levels of inflammation</a> than people in the modern US. This suggests that the experience of infections in early life may alter inflammatory responses in later life and prevent overzealous inflammation.</p>
<p>There is <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3635829/">abundant evidence</a> that high death rates in early life are linked to higher mortality in later life. Most such studies use data from pre-industrial populations, because an unfortunate drawback of studying modern people is that they tend to outlive the researchers. In these populations people born in years where the infant mortality rate is higher are consistently shown to have a higher mortality rate as adults. </p>
<p>There is, however, one issue with these findings. Infant mortality has decreased over time. So has adult lifespan. We assume a causal relationship between the two, but the link could be caused by something else, related to both of these, also changing across time. </p>
<p>For example, general improvements in living conditions could drive down infant mortality, through reduced infections, and increase adult lifespan, through improved diet. The link between reduced infant mortality and longer adult lifespan could therefore arise because of improvements in living conditions. To deal with this problem, a statistical technique called “de-trending” is used, so that the data provide information on infant mortality <em>relative to</em> the prevailing conditions. </p>
<h2>Lessons from pre-industrial Finland</h2>
<p>Using this technique, <a href="http://www.demographic-research.org/volumes/vol22/12/">recent studies</a> have found negligible associations between infant mortality rate and later-life mortality risk. Something missing from these studies, however, is data on disease in early life: infant mortality rate is used as a proxy, but infant death could be related to other factors. </p>
<p>Recently, we used data from church records on death rates from infections in pre-industrial Finnish people. These records contain information about births, marriage, and death for thousands of people. From the death data, we could determine, in every year, what percentage of the children died from an infection. We assumed that lots of deaths meant lots of the surviving children were infected. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/134081/original/image-20160815-15256-1auxzuq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/134081/original/image-20160815-15256-1auxzuq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/134081/original/image-20160815-15256-1auxzuq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/134081/original/image-20160815-15256-1auxzuq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/134081/original/image-20160815-15256-1auxzuq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/134081/original/image-20160815-15256-1auxzuq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/134081/original/image-20160815-15256-1auxzuq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Living to 106. Research suggests lifespan will continue to increase, perhaps until we can all expect to live to a hundred.</span>
</figcaption>
</figure>
<p>We used the “de-trending technique” to remove the change in child disease across time and studied how child infection exposure during the first five years of life influenced later life survival, cause of death, and fertility. The results were very clear: we found no link between infant disease exposure and later-life mortality, death from cardiovascular disease, or later-life fertility. Indeed, the evidence seems to be mounting that the link between early disease and adult lifespan is relatively weak. Similarly, the evidence that people in populations who experience frequent infections can moderate their inflammatory responses also weakens the link between infection and chronic inflammation. </p>
<p>Without a doubt, the fact that modern Londoners generally get enough food, have clean drinking water and access to free medical care will extend their lifespan. Current evidence suggests that <a href="https://www.rgs.org/NR/rdonlyres/228B6A47-DAE7-4A41-BA67-5CCE2137A13F/0/KS3_Population_factsheet.pdf">these processes</a> acting in adulthood seem to be the dominant factor.</p>
<p>All of this raises the inevitable question: at what point will human lifespan stop increasing? Certainly, every time a prediction is published, it is quickly exceeded. Many researchers agree that as long as living conditions continue to improve, average lifespan could increase for a little while longer, perhaps to the point at which it reaches 100 years. Research into life-extending treatments is exciting both scientifically and commercially, but given we don’t know what may be possible it is hard to predict the limits of human lifespan into the future. But that’s a whole other debate.</p><img src="https://counter.theconversation.com/content/63741/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Hayward does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Study investigates whether a decrease in serious childhood disease could be extending human lifespan.Adam Hayward, Research Fellow in Evolutionary Ecology, University of StirlingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/637842016-08-11T21:04:20Z2016-08-11T21:04:20ZA 400-year-old shark is the latest animal discovery to reveal the secrets of long life<figure><img src="https://images.theconversation.com/files/133787/original/image-20160811-18034-1rgkjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Julius Nielsen</span></span></figcaption></figure><p>For the <a href="https://www.researchgate.net/publication/257568506_Pangnirtung_Inuit_and_the_Greenland_Shark_Co-producing_Knowledge_of_a_Little_Discussed_Species">local Pangnirtung Inuit</a>, the Greenland shark is an animal that does not die easily.</p>
<blockquote>
<p>Dad used to say to me that sharks’ flesh has a hard time dying. The shark can be rotten, even sticky rotten, and when you touch the skin or the meat it still moves. You know, it is still alive but it is rotten.</p>
</blockquote>
<p>This might sound rather gruesome, but it turns out that this reputation has an element of truth to it. With an estimated lifespan of 400 years, the Greenland shark <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aaf1703">has just been reported</a> to be the longest-lived vertebrate on the planet. This is only the latest of a series of recent findings that push the boundaries of animal longevity, and it raises the perennial question of what factors enable some animals to achieve what we might call extreme longevity – lifespans that can be measured in centuries. </p>
<p>The key to becoming a long-lived species is for individuals to regularly die of old age (and not from disease or being eaten) in the first place. Experiencing age-related degeneration allows a species <a href="http://www.senescence.info/evolution_of_aging.html">to evolve resistance to it</a>. So an effective defence mechanism against predators, such as a thick external shell, must be in place first. Once this “safe space” has been achieved, living longer becomes a way to produce more offspring in the most efficient way, <a href="http://onlinelibrary.wiley.com/doi/10.1002/bies.950100408/abstract">especially when the food supply is intermittent</a>.</p>
<p>Here are five of the longest-living animals ever recorded.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133809/original/image-20160811-18034-10n2pxo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133809/original/image-20160811-18034-10n2pxo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133809/original/image-20160811-18034-10n2pxo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133809/original/image-20160811-18034-10n2pxo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133809/original/image-20160811-18034-10n2pxo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133809/original/image-20160811-18034-10n2pxo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133809/original/image-20160811-18034-10n2pxo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Of course, all this was ice in my day.</span>
<span class="attribution"><span class="source">Julius Nielsen</span></span>
</figcaption>
</figure>
<h2>1. Greenland shark</h2>
<p>As well as being a top predator itself, the Greenland shark has developed a defence against predators in the form of <a href="http://www.wired.com/2014/02/creature-feature-10-fun-facts-greenland-shark/">highly poisonous flesh</a>. Not being hunted in its early years allows the shark to pursue a more relaxed reproductive strategy. Females don’t reach reproductive maturity until <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aaf1703">an estimated age of 150 years</a>.</p>
<p>At the high latitudes where the shark lives, the limited amount of light during the winter means fewer plants and algae for other creatures to feed on, which can affect the amount of nutrients right up the food chain. So the ability to withstand the poor years and reproduce during the good years is key to the shark's’ survival, and a long lifetime is a great way to maximise the number of good years.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133812/original/image-20160811-11853-wo1i5t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133812/original/image-20160811-11853-wo1i5t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=405&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133812/original/image-20160811-11853-wo1i5t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=405&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133812/original/image-20160811-11853-wo1i5t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=405&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133812/original/image-20160811-11853-wo1i5t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=509&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133812/original/image-20160811-11853-wo1i5t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=509&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133812/original/image-20160811-11853-wo1i5t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=509&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Bottom of the sea, top of the pile.</span>
</figcaption>
</figure>
<h2>2. The ocean quahog</h2>
<p>The clam species <em>Arctica islandica</em> holds the record for the longest-lived animal known to science. We can measure its exact age by counting the annual bands in its shell, and this is how we identified a specimen (now popularly known as “Ming”) collected from Iceland that had lived <a href="http://www.sciencenordic.com/new-record-world%E2%80%99s-oldest-animal-507-years-old">for 507 years</a>.</p>
<p>In common with <a href="http://rspb.royalsocietypublishing.org/content/283/1836/20161364">many species of mollusc</a>, <em>A. islandica</em> grows more slowly and lives longer with increasing latitude. North of Iceland, they regularly live <a href="http://www.sciencedirect.com/science/article/pii/S0031018212000302">more than 300 years</a>, while further south in European and North American waters (where nutrients are less limited) their age limit is about 250 years. As with the Greenland shark, this is a useful reproductive strategy in nutrient-poor waters when there is no threat from predators.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133815/original/image-20160811-18014-1b7tcry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133815/original/image-20160811-18014-1b7tcry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133815/original/image-20160811-18014-1b7tcry.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133815/original/image-20160811-18014-1b7tcry.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133815/original/image-20160811-18014-1b7tcry.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133815/original/image-20160811-18014-1b7tcry.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133815/original/image-20160811-18014-1b7tcry.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Shark.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Bowhead_whale#/media/File:Bowhead-1_Kate_Stafford_edit_(16272151841).jpg">Who does that shark think he is?</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>3. Bowhead whale</h2>
<p>A bowhead whale collected during a whaling expedition off Alaska in 2007 was found to have the head of a <a href="http://www.nature.com/news/2007/070619/full/news070618-6.html">late 19th-century harpoon</a> embedded in its neck blubber. Its age was estimated by radiocarbon dating to be 211 years, making this the longest-lived mammal so far identified. Unlike other whales, the bowhead lives entirely in cold Arctic and subarctic waters. Once again, this suggests a strategy that uses longevity to compensate for low nutrients in the winter.</p>
<p><a href="http://www.medicaldaily.com/can-marine-biology-help-us-live-forever-bowhead-whale-can-live-200-years-cancer-316424">Analysis of bowhead whale DNA</a> suggests that the lack of natural predators has enabled the whale to evolve natural mechanisms to resist age-related decline. For example, cancer, while occasionally present, is extremely rare. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133814/original/image-20160811-18014-1wjt4b1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133814/original/image-20160811-18014-1wjt4b1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133814/original/image-20160811-18014-1wjt4b1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133814/original/image-20160811-18014-1wjt4b1.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133814/original/image-20160811-18014-1wjt4b1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133814/original/image-20160811-18014-1wjt4b1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133814/original/image-20160811-18014-1wjt4b1.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Time flies when you’re having fun.</span>
</figcaption>
</figure>
<h2>4. Giant tortoise</h2>
<p>The only terrestrial animal known to live beyond 200 years, the giant tortoise, is now confined to a few islands in the Indian and Pacific Oceans. An individual Aldabra giant tortoise <a href="http://news.bbc.co.uk/1/hi/world/south_asia/4837988.stm">died in a Kolkata zoo</a> in 2006 at an estimated age of 255 years. The oldest giant tortoise living now, a Seychelles tortoise called Jonathan <a href="http://www.bbc.co.uk/news/science-environment-35268755?ocid=socialflow_facebook&ns_mchannel=social&ns_campaign=bbcnews&ns_source=facebook">is reportedly 184 years old.</a></p>
<p>The giant tortoise employs a “belt and braces” approach to predators, and maintains its thick shell even while living on isolated predator-free islands. Without the fear of predators, the animal can –- like the Greenland shark and <em>A. islandica</em> – slow its metabolic activity right down, helping it to survive periods of drought <a href="https://animalcaseprofile.wordpress.com/2015/10/21/galapagos-giant-tortoise-geochelone-nigra/">when food supply is limited</a>.</p>
<h2>5. <em>Homo sapiens</em></h2>
<p>Jeanne Calment, who died in 1997 at the age of 122, was the oldest person (and probably the oldest land mammal) ever to have lived <a href="http://www.nytimes.com/1997/08/05/world/jeanne-calment-world-s-elder-dies-at-122.html">whose age has been precisely verified</a>. In fact, <em>Homo sapiens</em> is the only terrestrial mammal <a href="http://www.encyclopedia.com/topic/lifespan.aspx">known to live for more than 100 years</a>, and it is an interesting question whether this was the case even before the advent of organised agriculture.</p>
<p>One indicator of longevity in mammals seems to be brain size. This reflects an increased ability to adapt to a changing environment and, of course, is also an effective defence against predators. It seems that even early humans, if they could survive childhood, commonly lived to 70 or 80 years, <a href="http://biomedgerontology.oxfordjournals.org/content/55/4/B201.full.pdf+html">significantly longer than the other great apes</a>. The frequency with which modern humans live beyond 100 years may also be related to modern medical practice, or may simply reflect the sheer number of humans.</p><img src="https://counter.theconversation.com/content/63784/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Butler receives funding from the EU.</span></em></p>What are the oldest living animals on the planet?Paul Butler, Research Lecturer, School of Ocean Sciences, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/571492016-05-17T19:34:21Z2016-05-17T19:34:21ZSales increase by up to 56% when shoppers know a product will last<figure><img src="https://images.theconversation.com/files/121779/original/image-20160509-20595-1fod9rr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>From fashion to food and electronics, many industries are facing a backlash against cheaply made products that do not last. Sick of printers that break within two years, or suitcases that fall apart the second time you use them, there is a growing appetite for long-life guarantees – from the promise of the <a href="http://www.tomcridland.com/">30-year jumper</a> to the rise of <a href="http://www.theguardian.com/lifeandstyle/2016/feb/16/buy-me-once-online-store-lifetime-guarantee-product-reviews">shopping sites</a> dedicated to products that last a lifetime. </p>
<p>But we don’t always know whether a product will last when we buy it.</p>
<p>We recently carried out a study to see how consumption patterns would change if consumers were informed about product lifetime at the time of purchase. The European Economic and Social Committee has published the findings of this study, carried out by the <a href="http://www.univ-ubs.fr">University of Southern Brittany</a>, the <a href="http://www.sircome.com/">Sircome agency</a>, and the <a href="http://www.prf.jcu.cz">University of Southern Bohemia</a>.</p>
<p>Our main goal was to see whether displaying a product’s lifespan would influence a consumer’s decision to purchase. In other words, would our consumption patterns change if the lifetime was indicated? Would we choose the same products if we had this information? It seems we would not, and there are easy ways for manufacturers to inform of us of our options.</p>
<p>The experiment involved a sample of 2,917 participants from five European countries (Belgium, the Czech Republic, France, Spain and the Netherlands). We designed a fake shopping website, which consumers could use just as if it were Amazon or ASOS. (Participants did not know the site was fake.) Once they had checked out their shopping basket, participants were directed to a questionnaire which gauged various socio-economic and psycho-social indicators.</p>
<p>The results showed that if shoppers had information on product lifespan, they would choose to buy longer lasting items: on average, a product’s sales increased by 56% if its lifetime was longer than competing products’.</p>
<h2>The products we want to last</h2>
<p>Displaying the lifetime does not have the same impact on sales of all products. Of the products tested, purchases of suitcases (+128%) and printers (+70%) were influenced the most by displaying the lifetime. Why these two products?</p>
<p>Suitcases are the quintessential roaming product, giving them two characteristics which makes the consumer rank lifetime as a priority: the trials of transport make resilience a key factor, and any item used solely for travel will be brought out only occasionally. If it is used rarely, the consumer has every reason to hope it will last a long time.</p>
<p>As for printers, they have one of the shortest lifetimes of all household electronic goods, and people buy them because they need them, not for pleasure – two more good reasons why we would want them to last.</p>
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<a href="https://images.theconversation.com/files/121781/original/image-20160509-20599-1621488.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/121781/original/image-20160509-20599-1621488.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/121781/original/image-20160509-20599-1621488.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/121781/original/image-20160509-20599-1621488.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/121781/original/image-20160509-20599-1621488.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/121781/original/image-20160509-20599-1621488.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/121781/original/image-20160509-20599-1621488.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/121781/original/image-20160509-20599-1621488.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Graveyard of broken dreams.</span>
</figcaption>
</figure>
<p>Sales of smartphones are among the least affected by displaying lifetime (+41%) – possibly because they are bought for pleasure and having the latest model is a factor for many consumers.</p>
<p>It would also seem that the importance attached to lifetime increases with the amount that people are prepared to pay. In other words, lifetime is more important when purchasing top-of-the-range products (+49%) than bottom-of-the-range products (+44%).</p>
<p>A full 90% of participants said that they would be prepared to pay more for a dishwasher which would last two years longer. On average, they said they would be prepared to pay €102 more for that guarantee on a dishwasher priced between €300 and €500. The results also showed that the amount consumers were prepared to pay for a longer lasting product varied with the GDP of the country in which they lived.</p>
<h2>How should lifetime be displayed?</h2>
<p>Various display formats were tested: of these, a format similar to standard A to G energy consumption categories were the most effective in informing consumers. With this display, the market share of products with a longer lifetime than their competitors increased by 84%. </p>
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<a href="https://images.theconversation.com/files/121780/original/image-20160509-20581-1wc6qn4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/121780/original/image-20160509-20581-1wc6qn4.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/121780/original/image-20160509-20581-1wc6qn4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1263&fit=crop&dpr=1 600w, https://images.theconversation.com/files/121780/original/image-20160509-20581-1wc6qn4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1263&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/121780/original/image-20160509-20581-1wc6qn4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1263&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/121780/original/image-20160509-20581-1wc6qn4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1588&fit=crop&dpr=1 754w, https://images.theconversation.com/files/121780/original/image-20160509-20581-1wc6qn4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1588&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/121780/original/image-20160509-20581-1wc6qn4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1588&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">As easy as A to G.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Energy_label_2010.svg">Flappiefh</a></span>
</figcaption>
</figure>
<p>An indications of useful lifetime (indicated in terms of washing cycles, pages printed, and so on) came second, with an average increase in market share of 56% for products with a long lifetime.</p>
<p>Meanwhile, 80% of participants felt that the manufacturers were very to extremely responsible with regard to providing information about a product’s lifetime. </p>
<p>All these findings argue for legislation on product lifetime. There is no doubt that the reliability of the products purchased is important to consumers. The study showed that regulatory information would steer customers when purchasing products. </p>
<p>While not excluding their own share of responsibility in ensuring that their products last, consumers recognised that normal conditions of use would enable manufacturers to guarantee a minimum lifetime for their products. They also said they were prepared to pay more for products which last longer. </p>
<p>This points to an obvious policy response: an indication of lifetime should be mandatory on products, just as an energy rating is mandatory on many others. Providing an A to G rating for lifetime would allow manufacturers to meet consumers’ expectations, and consumers to make better choices.</p><img src="https://counter.theconversation.com/content/57149/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This document has been written by European University of Brittany 's researcher and does not represent the point of view of the European Economic and Social Committee. The interpretations and opinions contained in it are solely those of the authors. This study was carried out by the University of South Brittany, SIRCOME and the University of South Bohemia following a call for tenders launched by the European Economic and Social Committee. The information and views set out in this study are those of the authors and do not necessarily reflect the official opinion of the European Economic and Social Committee. The European Economic and Social Committee does not guarantee the accuracy of the data included in this study. Neither the European Economic and Social Committee nor any person acting on the Committee's behalf may be held responsible for the use which may be made of the information contained therein.</span></em></p><p class="fine-print"><em><span>Gaëlle Boulbry ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>We want products that last, it’s up to manufacturers to provide us with the information we need to buy them.Mickaël Dupré, Maître de conférences associé à l’IAE Brest, chercheur associé au LEGO, Université de Bretagne occidentale Gaëlle Boulbry, Maître de conférences, chercheur en marketing, Université Bretagne SudLicensed as Creative Commons – attribution, no derivatives.