Background:
Over the last 3 decades, age-standardised BMI and prevalence of obesity in adults has increased in all developed countries1. Worldwide, there has been an increase in prevention efforts in children, yet the major health and economic consequences of obesity occur in later life. Life course epidemiological modelling can provide insights into obesity progression and can guide priorities for targeted interventions in the future.
Methods:
We use a validated micro-simulation model of obesity progression in Australia2 to investigate future scenarios of the impact of targeted prevention of obesity in children/adolescents, young and older adults. The modelling takes into account BMI at transition to adulthood, age-specific adult BMI growth, informed by national data, and mortality associated with weight status. Using an input population representing around 17m adults from the 2014/15 National Health Survey, we simulated the number of healthy, overweight and obese adults between 2015 until 2040. We then investigated three scenarios: reducing mean BMI at transition to adulthood to 1995 levels (the assumed result of child/adolescent obesity prevention); and reducing weight gain of young and older adults, modeled independently using the lower 95% confidence bounds of observed age-specific weight gain (a reduction of around 100g per year).\
Results:
Prevention strategies differed in their short and long term effects. Reducing BMI at transition to adulthood had a delayed impact on adult obesity, whilst targeting adult weight gain had much earlier impact. The greatest reduction in obesity was achieved by reducing weight gain in young adults. Compared with reducing weight gain in older adults, this resulted in a two-fold reduction in the number of adults with obesity, by 2040.
Conclusion:
Obesity prevention efforts should occur throughout the life course. Our modelling suggests that young adults should be the focus of much more preventive efforts than is currently the case in Australia.