Successive generations of Australians are becoming fatter. The prediction of future trends in obesity is necessary in order to plan for future health service needs to manage the medical consequences of obesity, such as type II diabetes.
We used data from the Australian Longitudinal Study on Women’s Health to predict trends in the prevalence of obesity among Australian women taking into account: generational or cohort differences in mean levels and life course trajectories; general long-term, secular or period effects; and age-related weight gain. We combined these estimates with population projections from the Australian Bureau of Statistics under a range of scenarios of different rates of immigration, fertility and increases in life-expectancy.
We estimate that the proportion of obese women will increase from 25.5% in 2015 to just over 38% in 2035. Taking population increases into account this amounts to an increase from 2.3 million women in 2015 to between 4.5 and 4.8 million in 2035. Consequentially the proportions of health service costs associated with obesity are predicted to increase by about 46%.
These estimates are higher than might be inferred from the multiple cross-sectional National Health Surveys, which cannot fully account for generational differences.
The strong generational increases in the prevalence of obesity highlight the importance of reducing childhood obesity and then maintaining lower BMI throughout the life course, as well as reducing overweight and obesity among adults.