This is a shorter version of an article that appears in the latest issue of Perspectives, an opinion-led journal published by Baker IDI Heart and Diabetes Institute.
The prevalence of overweight and obesity in children and adolescents rose fairly dramatically in Australia from the mid-1980s to the mid-1990s. This was followed by a more moderate increase into the early 2000s, and then a levelling off.
The recent plateau is mirrored in the United States, many parts of Europe and Japan. But some paediatric population sub-groups within Australia continue to have a greater risk of overweight and obesity, including those who are socially disadvantaged and those of Middle-Eastern and Mediterranean ethnic backgrounds.
Effective prevention, as well as treatment, are necessary if we are to respond appropriately to the problem of child and adolescent obesity.
The Longitudinal Study of Australian Children provides information about the prevalence of overweight and obesity in four- and five-year-old children prior to school entry.
In the early 2000s, one in five children in this age group was overweight or obese, with prevalence being substantially higher in both disadvantaged and Indigenous children.
These data are based on body mass index (BMI: calculated as weight divided by height squared), which gives a reasonable measure of total body fatness.
But fat distribution is also important. Central body fat – fat distributed around the abdomen, leading to an increased waist circumference and an increased waist-to-height ratio – is associated with an increased prevalence of risk factors for heart disease and diabetes.
Simply put, if waist-to-height ratio is greater than 0.5 (i.e. if your waist is more than half your height), then health risks increase in both adults and children.
In Australia, the proportion of school-aged children with a waist-to-height ratio greater than 0.5 has steadily increased from 8.6% in 1985 to 13.6% in 1995 and 18.3% in 2007.
It appears that Australian children are changing shape to a more central fat distribution. And although the implications of this for future health remain unknown, it’s likely to have an adverse effect.
The 2004 NSW Schools Physical Activity and Nutrition Survey, which included a biomarker sub-study in randomly selected 15-year-old students, showed a high prevalence of chronic disease risk factors in adolescents.
In particular, risk factors for heart disease (such as high blood pressure and abnormal blood lipids), diabetes (raised insulin levels) and fatty liver disease were present in many obese, as well as overweight, adolescent boys.
Obese girls also had a higher risk of disease, although they didn’t seem to be as adversely affected as adolescent boys.
The propensity for body size, eating and physical activity behaviours and risk factors to follow a similar path from adolescence through to adulthood suggests health-care systems can expect a greater burden of disease from obesity-related conditions when today’s young people reach adulthood.
Given the extent of the problem of child and adolescent obesity, governments and communities have rightly been concerned about how to tackle the issue.
Investment in a range of prevention interventions is needed for medium- or long-term decrease in the number of obese people, in a way that affects all members of the community including children, young people and their families.
At the same time, there’s also a need to provide effective and accessible treatment services for those people already affected by obesity.
Dos and don'ts for prevention
In 2009, the National Preventative Health Taskforce released detailed recommendations on obesity prevention in Australia. The common theme of the recommendations was enabling healthy personal choices around eating and physical activity, through modification of the broader environment.
Other important recommendations included:
the use of a range of multi-level, multi-faceted interventions that influence different aspects of the food and physical activity environments;
engagement of national, state and local governments; the media, a range of industries; local communities and individuals; and
the need for political leadership, supporting a coordinated, inter-sectoral approach.
But there are a some approaches to obesity prevention – known as “the futility of isolated initiatives” – that should be avoided because they are extremely unlikely to work. These include:
focusing interventions is one setting, such as schools, without engagement of the family or broader community;
using a single approach, such as social marketing, in the absence of any other community-level change; and
“cherry-picking” a few interventions without using the underpinning principles noted above.
Not leaving treatment behind
Efforts also need to be made for treating those who are already affected by obesity. Unfortunately, clinical services for obese children and adolescents are currently very limited in all states and territories.
Some of the potential strategies for intervention include:
Developing and implementing a comprehensive and coordinated model of care for moderate and severe obesity, including paediatric obesity, across primary, secondary and tertiary levels of care;
resourcing of multidisciplinary paediatric obesity management services within the public health system;
resourcing bariatric surgery services in the public-health system within each state and territory, including services for selected older adolescents;
establishing dedicated training posts so nurses, allied health professionals and doctors can be given training in paediatric obesity management; and
implementing undergraduate and postgraduate health professional training in the assessment and management of people affected by obesity.
These initiatives are the responsibility of state and territory government health departments, universities and health professional colleges and bodies.
Both effective prevention of obesity, as well as treatment of those already affected by it, are necessary if we are to respond appropriately to the problem of child and adolescent obesity.
There are a range of potential solutions, but perhaps the biggest challenge is summoning the political will to address them.