Diabetes as a predictor of change in functional status among older Mexican Americans: a population-based cohort study.

Abstract

Epidemiological studies have demonstrated that older Mexican Americans are at high risk for type 2 diabetes and its complications. Type 2 diabetes leads to a more rapid decline in functional status among older Mexican Americans with diabetes. This study was designed to examine the impact of diabetes on change in self-reported functional status over a 2-year period among older Mexican Americans with diabetes. We performed a longitudinal analysis with repeated measurements of functional limitations in a cohort of Mexican Americans aged > or =60 years in the Sacramento Area Latino Study on Aging (SALSA). Diabetes was diagnosed on the basis of self-report of physician diagnosis, medication use, and fasting plasma glucose. Functional status was measured by assessment of activities of daily living (ADL) and instrumental activities of daily living (IADL) at baseline and 1 and 2 years. Of 1,789 SALSA participants, 585 (33%) had diabetes at baseline. Diabetic subjects reported 74% more limitations than nondiabetic subjects in ADL (summary score for number of limitations, 0.99 vs. 0.57; P = 0.002) and 50% more limitations in IADL (summary score for number of limitations, 7.83 vs. 5.25; P < 0.0001). The annual rate of increase in limitations of ADL and IADL was 0.046 and 0.033 (log scale) on each scale among diabetic subjects compared with 0.013 and 0.003 (log scale) among nondiabetic subjects (P < 0.0005). Complications of diabetes were found to increase ADL and IADL limitations among diabetic subjects. Longer duration of diabetes was also associated with an increase in ADL and IADL limitations. There was lower baseline functional status and a more rapid decline in functional status among older Mexican Americans with diabetes versus those without diabetes.