Prevalence of disability in Australian elderly: impact of trends in obesity and diabetes

OBJECTIVE: We aimed to estimate the impact of past and future changes in obesity and diabetes prevalence in mid-life on disability prevalence for adult Australians. METHODS: We analysed data from the Australian Diabetes, Obesity and Lifestyle study (AusDiab) including participants aged 45-64years, disability-free at baseline (1999/2000) with disability information at follow-up (2011/12) (n=2107). We used coefficients from multinomial logistic regression to predict 10-year probabilities of disability and death from baseline predictors (age, sex, obesity, smoking, diabetes and hypertension). We estimated the prevalence of disability attributable to past (1980) and expected future (2025) changes in obesity and diabetes prevalence using the life table approach. RESULTS: We estimated that the prevalence of disability for those aged between 55 and 74years would have been 1697 cases per 100,000 persons less in 2010 (10.3% less) if the rates of obesity and diabetes observed in 2000 had been as low as the levels observed in 1980. However, if instead the prevalence of obesity and diabetes had been as high as the levels expected in 2025, then the prevalence of disability would have been an additional 2173 per 100,000 persons (an additional 13.2%). CONCLUSIONS: We demonstrate, for the first time, a substantial potential impact of obesity and diabetes trends on disability amongst those aged 55-74years. In Australian adults by 2025 we estimate that around 26% of disability cases would have been avoidable if there had been no change in obesity and diabetes prevalence since 1980. A similar impact is likely around the world in developed countries.