The Association between Lower Extremity Muscular Strength and Cognitive Function in a National Sample of Older Adults

BACKGROUND: We evaluated the association between lower extremity muscular strength and cognition among older adults in the United States. METHODS: Data from the 1999–2002 National Health and Nutrition Examination Survey was used to identify 1508 older adults, between 60–85 years. Muscle strengthening activities were assessed via self-report. Participation in physical activity was determined from self-report data. The DSST was used to assess participant executive cognitive functioning tasks of pairing and free recall. A Kin-Com MP isokinetic dynamometer (Chatanooga Group Inc.) was used to assess lower extremity strength, expressed as absolute strength (N), relative strength (N/body weight in kg), and high (<245.75 N) vs. low (≤245.75 N) absolute strength based on the median levels of strength. RESULTS: Lower extremity strength (β = 0.01; 95% CI: 0.0008–0.03; p = 0.039) was associated with higher cognitive performance, independent of age, muscle strengthening activities, physical activity and other covariates. In an adjusted multivariate logistic regression model, those with high (vs. low) strength had a 34% reduced odds of having low cognitive function (OR = 0.66; 95% CI: 0.46–0.93; p = 0.02). CONCLUSION: In this nationally representative sample of older adults, there was a positive association between elevated lower extremity muscular strength and cognitive functioning.