The Association Between Muscle Weakness and Incident Diabetes in Older Mexican Americans.

OBJECTIVES: A natural decline of muscle strength occurs during the aging process; however, preserving muscle strength may lower the rate of many preventable diseases such as diabetes, especially in higher risk populations. The purpose of this study was to examine the sex-specific association between muscle weakness and incident diabetes in older Mexican Americans.

DESIGN: Observational, longitudinal study.

SETTING: Urban and rural households in the Southwestern United States.

PARTICIPANTS: A subsample of 1903 Mexican Americans aged at least 65 years without diabetes at baseline were followed for 19 years.

MEASUREMENTS: Muscle weakness was assessed with a hand-held dynamometer and was normalized to body weight (normalized grip strength). Male and female participants were categorized as weak if their normalized grip strength was ≤0.46 and ≤0.30, respectively. Sex-stratified Cox proportional hazard regression models were used to determine the association between muscle weakness and incident diabetes (self-reported) when using age as an entry variable and after adjusting for education, employment status, instrumental activities of daily living disability, interview language, marital status, and obesity. A sensitivity analysis was performed to account for influential outliers for the outcome variable (incident diabetes) and the model was re-run.

RESULTS: The hazard ratio for incident diabetes was 1.05 (95% confidence interval: 1.02-1.09; P < .001) in weak vs not-weak male participants and 1.38 (95% confidence interval: 1.35-1.41; P < .001) in weak vs not-weak female participants, after adjusting for relevant covariates.

CONCLUSIONS: Muscle weakness was associated with an increased rate of diabetes in older male and female Mexican Americans. Health professionals should encourage activities that preserve muscle strength, thereby preventing the incidence of diabetes in older Mexican Americans.