Older adults with diabetes are at least 50% more likely to have a physical disability than those without diabetes, according to the results of a new systematic review and meta-analysis published in The Lancet Diabetes & Endocrinology.

Previous studies examining the risk of disability associated with diabetes have produced varying results, ranging from no association, to a doubling of risk. The new study is the first meta-analysis to pool estimates taken from earlier studies, providing a more reliable estimate of the likely risk of disability associated with diabetes.

Led by Dr Anna Peeters and Dr Evelyn Wong, of the Baker IDI Heart and Diabetes Institute in Melbourne, Australia, a team of researchers examined the scientific literature to identify more than 3000 studies looking at the association between diabetes and disability. The researchers then narrowed this down to eventually include 26 studies in the meta-analysis, after removing studies which were irrelevant or not suitable for inclusion.

Disability was defined in terms of both impaired mobility, and functional disability (impaired ability to perform activities of daily living, such as bathing or eating, and instrumental activities of daily living such as using the phone, shopping, and using transport).

Overall, the analysis showed that people with diabetes are at roughly 50% - 80% increased risk of physical disability, compared to people without diabetes. Although the study did not differentiate between Type 1 and Type 2 diabetes, the authors note that the majority of studies included in the analysis were based on studies of older people (over 65 years), among whom Type 2 diabetes is predominant.

According to Dr Peeters, "The reasons why diabetes is associated with physical disability are still unclear, although several mechanisms have been suggested. It's possible that the high blood glucose concentrations experienced by people with diabetes might lead to chronic muscle inflammation, eventually resulting in physical disability, and some studies have shown that diabetes is associated with rapid and worsening muscle wasting. The complications associated with diabetes, such as heart disease, stroke, and kidney disease, can all result in disability. As the world's population ages, and diabetes becomes more common, it seems clear that we will see an increased need for disability-related health resources, which health systems around the world need to be prepared for."*

Writing in a linked Comment, Dr Edward Gregg, of the Centers for Disease Control and Prevention, in Atlanta, USA, points out that the new analysis necessarily focuses on studies of older people in higher-income countries, because there is a paucity of quality research available outside these groups.

According to Dr Gregg, "Diabetes often causes more relative damage in middle age than in older age (ie, relative to their same-aged, non-diabetic peers); the same might be true for disability. In view of the fact that the greatest increase in diabetes cases in low-income and middle-income countries are expected in middle-aged adults, and that a large prevalence of disability could have damaging health and economic implications, more thorough examination of function across the full age spectrum of adults is also needed."