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Asbestos still haunts those exposed as kids in mining towns

The relationship between asbestos exposure and diseases such as malignant mesothelioma and lung cancer is well established. But now other diseases not typically associated with asbestos may possibly be…

Growing evidence suggests asbestos exposure may cause many more diseases than we thought. Natalie Blackburn

The relationship between asbestos exposure and diseases such as malignant mesothelioma and lung cancer is well established. But now other diseases not typically associated with asbestos may possibly be linked to occupational and non-occupational forms of exposure.

Asbestos refers to a number of naturally occurring minerals that have crystallised to form long thin fibres and fibre bundles. There are three main types that have been used commercially – crocidolite (blue asbestos), amosite (brown asbestos) and chrysotile (white asbestos).

The difference between these types has to do with the shape and size of their fibres. Crocidolite and amosite have long, straight fibres, while chrysotile fibres are short and curly. The shape of these fibres is thought to be central to the damage they do to human health. The long straight fibres, in particular, are thought to easily penetrate into the lungs.

So although all types of asbestos have been found to cause asbestos-related diseases, some types lead to more of these diseases than others. Blue asbestos (the type that was mined at Wittenoom, Western Australia) is the worst for human health, followed by amosite, and then chrysotile.

White chrysotile asbestos fibres are thought to cause certain diseases. Asbestorama/Flickr

Asbestos and health

Diseases most commonly attributed to asbestos exposure are malignant mesothelioma, asbestosis and lung cancer. There’s a clear relationship between the amount of asbestos exposure and the risk of developing mesothelioma and asbestosis, with the risk increasing as the level of exposure increases.

Malignant mesothelioma is a diffuse cancer that spreads over the lining of the lung or stomach. It has a long latency period, rarely developing within 15 years of first exposure. And it is universally fatal – the average survival rate, after diagnosis, is nine months.

Malignant mesothelioma is very rare in people who haven’t been exposed to asbestos. In England, cases were established from autopsy reports between 1910 and 1940, and the disease became more frequently diagnosed in the 1950s. The link between asbestos (crocidolite) exposure and mesothelioma was formally established in 1960.

Asbestosis is defined as “fibrosis of the lungs caused by asbestos dust”. Patients with well-established asbestosis usually present with symptoms of shortness of breath and a dry cough. It’s a progressive disease but it’s not necessarily fatal. The first case of asbestosis was described in medical literature in 1906, in a 33-year-old man who had worked in an asbestos textile factory for 14 years.

Children who grew up in Wittenoom, Western Australia between 1943-66 are dying of asbestos-related diseases in adulthood. Five Years/Wikipedia Commons

Other kinds of cancers are also more prevalent among workers exposed to occupational levels of asbestos than the general population. These include brain cancers, blood-related disorders (such as leukaemia), kidney cancer, cancer of the larynx, stomach and colorectal cancer. But the evidence that asbestos causes these other diseases is limited, mainly due to a lack of proof for an exposure-response relationship.

The International Agency for Research in Cancer has recently stated that asbestos exposure causes ovarian cancer. But there’s still some debate about this link in the scientific literature.

Few studies have found an excessive risk of these other cancers developing in people exposed to asbestos. Fewer still have found or reported a causal link.

Will we ever know for sure?

Former workers and residents of the blue asbestos mining and milling town of Wittenoom, Western Australia have been followed up through cancer and death registries and by regular questionnaires for over 30 years. Our latest study has revealed a relationship between cancers other than mesothelioma among people who, as children, lived in Wittenoom.

Now adults, this group were exposed to blue asbestos before the age of 15. We have found an increased risk of brain cancer among both the males and females of this group.

We also found higher rates of leukaemia, prostate and colorectal cancer among males, and ovarian cancer among females, compared with the general Western Australian population. These are very rare cancers, so it’s very difficult to state with absolute certainty that they’re caused by exposure to asbestos. Despite the significantly increased rates of cancer within this group, we may never know for sure whether asbestos is implicated.

Blue asbestos in Wittenoon, Western Australia still circulates in the air well after the town’s closure. oemebame/Flickr

The Wittenoom group also have a high rate of heart disease compared with the Western Australian population. Again, the evidence proving that exposure to asbestos causes heart disease is limited. Although we found an increased risk of heart disease in this group, we didn’t find that the risk increased as the level of asbestos exposure increased.

The Wittenoom children are still young and heart disease is not a major cause of death among them. Perhaps a link between heart disease and asbestos exposure will become apparent as they age. Recent work from the United Kingdom has shown that ischaemic heart disease and cerebrovascular disease were more prevalent among a large group of British workers exposed to occupational levels of asbestos. In that study, longer exposure was associated with a greater risk of ischaemic heart disease.

One of the ways we can prove that a disease is caused by asbestos is to find that the risk of disease increases with the amount of asbestos exposure. Where we do not find that relationship, we have to concede that the disease may be caused by other factors the group have in common. We may not have looked for such factors or perhaps were unable to look for them in our studies.

Following up the former Wittenoom children may reveal links between asbestos exposure and these other diseases. The longer they are followed up, the more information we will learn about the diseases they develop, and whether asbestos exposure is the cause.

This knowledge may help those still being exposed to asbestos, because we would be able to correctly identify diseases they may present with. But the best way of preventing asbestos-related diseases is to avoid exposure altogether.

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8 Comments sorted by

  1. Debra Joan Smith

    Account Executive

    This is a courageous effort to get this knowledge out to everyone everywhere who needs to know. And YOU need to know this!

    Last year I sat with a man who was dying of asbestos exposure here in Canada. He was dying because he had worked in a paper mill years before to support his family. I got involved to help his wife Alice get a break and he and I got along so he accepted my company in his extremis. I remember that he could ask me questions that he did not want to distress his family with like…

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  2. chris matthews

    mediator

    Thank you for this article. Having practiced in workers compensation I have also dealt first hand with those who have been blighted by asbestos. But as you have demonstrated it is not only workers at risk. Wives and children are also susceptible.

    These victims need assistance but James Hardie has bailed on its responsibility.

    I personally would be very keen to take part in a national lottery to raise funds for treatment and research.

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  3. Sue Ieraci

    Public hospital clinician

    Thank you for an informative article.

    It was interesting to look at the data in the actual paper you linked to, and how the outcomes were affected by smoking. For example, in the male cohort, the standardised mortality ratios in men who had ceased smoking or never smoked were the same as for the general population (CIs crossing 1).

    While it's important to hold big corporations responsible for exposing their workers, this data points all the more to the synergistic effects of tobacco smoking - whose even larger multinational corporations still market legally around the world.

    In particular, this information makes it essential that anyone who has been exposed to asbestos must give up smoking, or never take it up.

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    1. Debra Joan Smith

      Account Executive

      In reply to Sue Ieraci

      You know Sue, I always enjoy your caring and insightful comments. It is lovely to meet someone who cares so much about her country and its people. YOUR point is a really important one and in truth, Danny had been a smoker way back then.

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  4. Melissa Haswell-Elkins

    Assoc Prof Public Health and Community Medicine

    Thanks Alison, very interesting and important paper and area. i used to do research on liver fluke infection and cholangiocarcinoma in the 90's and was interested to see very similar carcinogenic pathways proposed for asbestos. agents that stimulate but don't get cleared by the immune response would seem to raise the risk wherever they end up in the body, to varying extents. have their been any studies tracking where asbestos gets deposited when absorbed?

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  5. Debbie Jeffrey

    Screenwriter

    What if you shipped the people out to a much healthier part of Australia and shut that part down in a giant bubble, a bigger version of the UK's Eden Project?

    On the basis that the human body regenerates every year, these people could escape effects of asbestos if the body can be reprogrammed to act in a different way and if a way can be sought to remove the actual asbestos or effects of it. The reprogramming is possible and is done by oneself in association with a medical and spiritual practitioner. Before you scoff, please look up the works for Dr. Deepak Chopra and consider his findings on an intellectual basis.

    Just thoughts.

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  6. Tasma Dawson

    Home Duties

    Hi, My name is Tasma and I live in Mandurah, Western Australia. I was born in 1969 in the town of Wittenoom and lived there for around 3 years of my life with my parents and 7 siblings. My father worked at the asbestos mine in Wittenoom and he created a sandpit in our yard for us children but unfortunately the sand come from the asbestos mine that my father worked at. Both my parents have died of cancers (lung - mother, prostate -father). One of my sisters had ovarian cancer (currently in remission…

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