The impact of trends in obesity and diabetes on physical disability in Australian elderly

INTRODUCTION: Obesity and diabetes have been shown to increase the risk of disability in old age. As our population ages, disability will be an increasingly important measurement of overall health. We aimed to estimate the impact of changes in obesity and diabetes prevalence in middle age on disability prevalence in the elderly.

METHODS:   We analysed data from the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) including participants aged 45-65 who were free of disability at baseline (1999/2000) with available disability information at follow-up (2011/12) (n=1982). Multinomial logistic regression analysis (outcomes:  alive with no disability as reference, disability or death 12 years later) was used to identify the association between a number of predictors at baseline (age, sex, obesity, smoking, diabetes and hypertension) with disability and death 12 years later. Coefficients for predictors were used to estimate the study population’s risk of disability and death over 12 years. We compared these risks to hypothetical populations with 50% less obesity and diabetes at baseline (2000) to approximate prevalence in 1980.

RESULTS: Obesity increased the risk of disability (OR 3.83 (95% confidence interval (CI) 2.19-6.70)) and death (OR 1.86 (95% CI 1.17-2.95)). Diabetes increased the risk of disability (OR 1.98 (95% CI 1.12-3.52)) and death (OR 1.67 (95% CI 1.17-2.95)). Our study sample had a 9% risk of developing disability and 7% risk of death over the twelve year follow-up. A hypothetical halving of obesity and diabetes prevalence at baseline led to a 19% and 7% reduction in 12-year risk of disability and death respectively.

CONCLUSIONS: If obesity and diabetes prevalence in 2000 was half of that observed, middle age Australians would have developed 19% less disability by 2012.