Impairments and comorbidities explaining the association between diabetes mellitus and lower extremity disability: The Women’s Health and Aging Study.

OBJECTIVE: To elucidate the role of diabetes-related impairments and comorbidities in the association between diabetes and physical disability, this study examined the association between diabetes and lower extremity function in a sample of disabled older women. RESEARCH DESIGN AND METHODS: Cross-sectional analysis of 1,002 women (aged >or=65 years) enrolled in the Women's Health and Aging Study (one-third most disabled of the total community-dwelling population). Diabetes and other medical conditions were ascertained by standard criteria that used multiple sources of information. Functional status was assessed using self-reported and objective performance measures. RESULTS: Women with diabetes were significantly more likely to have cardiovascular diseases, peripheral nerve dysfunction, visual impairment, obesity, and depression. After adjustment for age, women with diabetes had a greater prevalence of mobility disability (odds ratio [OR] 1.85, 95% CI 1.12-3.06), activities of daily living disability (1.61, 1.06-2.43), and severe walking limitation (2.34, 1.56-3.50), and their summary mobility performance score (0-12 scale based on balance, gait speed, chair stands) was 1.4 points lower than in nondiabetic women (P < 0.001). Peripheral artery disease, peripheral nerve dysfunction, and depression were the main individual contributing factors; however, none of these conditions alone fully explained the association between diabetes and disability. Conversely, only after adjusting for all potential mediators was the relationship between diabetes and disability reduced to a large degree. CONCLUSIONS: Even among physically impaired older women, diabetes is associated with a major burden of disability. A wide range of impairments and comorbidities explains the diabetes-disability relationship, suggesting that the mechanism for such an association is multifactorial.