Technical Paper 1:
Obesity in Australia: a need for urgent action
4.10 - Build the evidence base, monitor and evaluate effectiveness of actions
There is a clear need to increase the evidence base regarding obesity prevention and management through research, evaluation, monitoring and surveillance. This requires a much higher investment in the research and evaluation of weight reduction interventions and the causes of obesity. There is a need to develop a comprehensive national research agenda for obesity. It is also vital to develop an agreed national assessment tool and reporting levels for overweight and obesity, particularly as they relate to children, young people and minority groups. A specific research agenda needs to be developed with appropriate levels of public and private funding, which must be supported by improved monitoring and harmonisation of surveillance systems across Australia. Existing and future interventions require well-designed, rigorous evaluation (including economic analysis such as the assessment of cost-effectiveness) if the relative lack of evidence on obesity prevention and management is to be addressed.
The Taskforce has identified the need to establish a comprehensive national surveillance system focused on the behavioural, environmental and biomedical risk factors for chronic disease (including factors such as food availability and food composition) to track and report on performance and outcomes, including the impact on health inequalities. Expanding the national nutrition and physical activity survey program through the inclusion of biomedical data would be an important input to such a system.
Develop a comprehensive national research agenda for overweight and obesity.
Expand the national nutrition and physical activity survey to cover adults, children and the Indigenous population, and ensure the inclusion of biomedical risk factors for chronic disease. This survey needs to become a permanent national five-yearly study.
National data collection – adults
Australia’s major investment in monitoring the nutrition, physical activity and weight patterns of the Australian population is currently undertaken through the now triennial National Health Survey (NHS), conducted by the Australian Bureau of Statistics (ABS). The last three surveys were conducted in 1995, 2001 and 2004–2005. Data
is collected through personal interviews with all respondents, except for children (parents/carers are interviewed on the child’s behalf). Among a range of health data, the NHS collects information on nutrition (fruit and vegetable intake), leisure time physical activity, and height and weight (self-reported).
Top of Page
The most recent National Health Survey (the 2007–2008 survey, for which data collection was completed in July 2008) collected both self-reported and measured height and weight information from all participants aged over five years, as well as measured waist and hip data. Results from this survey are expected to be released in March 2009.
Measured height and weight from a sample representative of the population and for which data is currently available was last collected in 1999–2000 (the Australian Diabetes, Obesity and Lifestyle study, AusDiab). This is a longitudinal population-based study that was repeated in 2004–2005. There are plans for a 10-year follow-up to the initial survey in 2009–2010, inviting all previous participants to take part once again, as well as recruiting another cohort of new respondents from the general population.
Prior to this, the 1995 National Nutrition Survey was the largest and most comprehensive Australian survey of food and nutrient intake, dietary habits and body measurements (height, weight, waist and hip circumference, and blood pressure). It was conducted by the ABS in 1995–1996 among around 13,800 respondents from across Australia. Information on food and beverage intake, the usual frequency of intake, food-related habits and attitudes, and physical measurements were collected from people aged two years or more.
The difference between measured and self-reported height and weight is important, as measured data are likely to be more accurate and self-report data will likely underestimate true BMI.
National data collection – children
The latest national-level data collected on children’s weight occurred through the Kids Eat, Kids Play survey, the first national survey of Australian children’s nutrient intake since 1995 and the first national children’s physical activity survey since 1985. The survey involves 4000 children aged 2–16 years. Field work was completed in September 2007. Food, beverage and dietary supplement intake information were collected to calculate nutrient intake, while activity patterns and physical measurements (weight, height and waist circumference) were also recorded. Results were released in October 2008.
Top of Page
National data collection – adolescents
An ongoing national survey to commence in 2009 (funded by state Cancer Councils, the Cancer Council Australia and the National Heart Foundation of Australia) aims to monitor overweight/obesity prevalence, diet and activity among a nationally representative sample of around 20,000 secondary school students from year levels 8 to 11. Measured height, weight and waist circumference, food intake, dietary habits, physical activity, sedentary behaviour, barriers and enablers of physical activity and data on the school food and activity environment will be collected.