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

Highlights

• We analyse the impact of obesity and diabetes trends in mid-life on disability.

• Obesity prevalence between 1980 and 2000 contributed to 14% of avoidable disability.

• If obesity trends continue in 2025, we estimate further 13% increase in disability.

• Increasing obesity prevalence will impact on our working and ageing population.

Abstract

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 45–64 years, 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 74 years 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 55–74 years. 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.

Introduction

Obesity and diabetes, two known predictors of disability (Wong et al., 2015), have increased in prevalence over the last three decades with obesity increasing more rapidly amongst the younger adult population (Gordon-Larsen et al., 2010, Ogden et al., 2006). These trends pose a challenge to an ageing population. Significant lifestyle predictors in mid-life for disability in old age include obesity, diabetes, smoking and hypertension (Wong et al., 2015). Whilst there have been improvements in smoking prevalence and better management of hypertension over time, based on trends in the first decade in the 21st century in the United States of America and Australia, obesity has been projected to increase between 34% and 43% in adults (Huffman et al., 2012, Walls et al., 2012, Magliano et al., 2008) by 2020–2025. Diabetes and glucose intolerance have also been projected to increase rapidly over the same time period (Magliano et al., 2008).

Recent trends of disability in the United States have shown an increase in disability amongst those aged 40–64 years and 55–64 years (Hung et al., 2011, Martin and Schoeni, 2014, Freedman et al., 2013). It is likely that this will impact on the population's productivity, pension schemes, health and aged care resources. Similar trends, measured as quality adjusted life expectancy, years lived with disability or compression of morbidity, have been demonstrated in both middle-aged adults as well as those aged over 65 years (Wen and O'Rance, 2008, Crimmins and Beltrán-Sánchez, 2011, Van Baal et al., 2006, Stewart et al., 2009). The recently updated Global Burden of Disease Study reported a shift in the burden of disease from premature death to years lived with disability (Murray et al., 2012). Projection studies for disability adjusted life expectancy and compression of morbidity over the next decade have concluded that even with declining smoking trends, the impact of obesity will lead to increased years lived with disability or compression of morbidities(Van Baal et al., 2006, Stewart et al., 2009). If current obesity trends continue, we can anticipate a rise in onset of new disability as our population ages. This has important implications with regard to those around retirement age in terms of their ability to prolong their productive years and continuing to live independently. To date, whilst there has been an analysis of the impact of obesity and smoking trends on life expectancy, little is known of the future impact of mid-life obesity and diabetes on the prevalence of disability. Disability, particularly in terms of limitations to activities of daily living (ADL), is an important general health measure as it relates to loss of independent living with early onset resulting in early retirement and disability pensions (Burdorf et al., 2014).

We aimed to estimate the likelihood of surviving free of disability up to age 75 years in Australia based on mid-life obesity and diabetes prevalence. We modelled the contemporary population using longitudinal data from the Australian Lifestyle, Obesity and Diabetes study (AusDiab) and estimated changes in disability prevalence associated with future (2025) and past (1980) midlife obesity and diabetes levels.