Technical Paper 1:
Obesity in Australia: a need for urgent action
Being overweight or obese is one of the most common risk factors associated with increased mortality and morbidity globally. Other common preventable risks include poor infant feeding practices, low birthweight, childhood and maternal under-nutrition, unsafe sex, use of tobacco, harmful use of alcohol, unsafe water and lack of sanitation. Worldwide, these preventable risks contribute each year to over 40% of the 58 million deaths and one-third of the loss of healthy life-years.
Recent data from the Organisation for Economic Co-operation and Development (OECD) indicate that the most marked shifts in body mass index (BMI) distributions over the past two decades in a range of OECD countries have occurred in Australia, England and the United States.
Based on past trends, the prevalence of obesity and overweight in Australia is predicted to increase significantly over the next decade across all age groups to around two-thirds of the population. The report examined past and projected future trends in adult overweight and obesity in 11 OECD countries. The authors found a projected continued increase in obesity prevalence for all countries. While there were differences between countries, trends suggested greater levelling-off or even decreases in rates of overweight alone. They considered the results to suggest that diverging forces are pushing overweight and obesity prevalence in opposite directions: it appears that the strong effects of obesity-promoting environments (that is, aspects of physical, social and economic environments promoting the development of obesity) have been consolidating over the course of the past two to three decades.
In addition, they postulate that successive generations have become increasingly aware of the health risks associated with lifestyle choices, and in some cases are more capable of dealing with environmental pressures due to the long-term effects of changing education and socioeconomic conditions.
The authors found that the distribution of overweight and obesity in these countries showed consistent and pronounced disparities by education and socioeconomic condition in women, with higher levels of education and socioeconomic status (SES) associated with significantly lower prevalence, while mixed patterns were found for men. The analysis also found that inequalities in obesity related to education levels in women seemed to increase in Australia. The findings also emphasised the spread of overweight and obesity within households, which was concluded to suggest that health-related behaviours, especially those concerning diet and physical activity, are likely to play a larger role than genetic factors in determining the convergence of BMI levels within households.
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The authors highlighted the implications of the gender difference in socioeconomic gradients. These included the higher prevalence of obesity in women in disadvantaged socioeconomic groups, meaning that children of women in these groups are more likely to be overweight or obese, which will be likely to perpetuate the link between obesity and socioeconomic disadvantage as these children will most likely experience fewer opportunities of attaining higher SES.
A report released in December 2008 on the 2005–2006 National Health and Nutrition Examination Survey (NHANES) reveals a disturbing trend in the United States: based on measured height and weight, an estimated 32.7% of US adults 20 years and older were classified as overweight, 34.3% as obese and 5.9% as extremely obese (BMI of 40 and above). Compared with US health survey data collected since 1988, the 2005–06 survey was the first in which the prevalence of adult obesity exceeded the level of adult overweight. While the prevalence of obesity in the United States has more than doubled since 1980 (although the increase between 2003–04 of 32.2%, and 2005–06 of 34.3%, was not statistically significant), the prevalence of overweight has remained stable over the same time period.