Cognitive ability and physical performance in middle-aged African Americans

OBJECTIVES: To investigate the association between cognitive ability and physical performance in a population-based sample of middle-aged African Americans. DESIGN: Cross-sectional study, 2000/2001. SETTING: St. Louis, Missouri. PARTICIPANTS: Nine hundred ninety-eight African Americans born between 1936 and 1950. MEASUREMENTS: Cognitive function was measured using the Mini-Mental State Examination (MMSE) and the Animal Naming Test of verbal fluency. Physical performance was measured using eight tests: chair stand, semitandem stand, tandem stand eyes open, tandem stand eyes closed, one-leg stand, usual gait speed, grip strength, and peak expiratory flow. RESULTS: There was a statistically significant and monotonic (progressively worsening) trend of the eight physical performance measures across cognitive tertiles in all eight MMSE analyses and five of eight Animal Naming analyses, controlling for age, sex, education, geographic area, depressive symptoms, and comorbid conditions. CONCLUSION: The association between physical performance and cognitive function appears robust. The results extend previous reports for adults aged 65 and older to a measure of verbal fluency and to a population-based sample of African Americans aged 49 to 65. Further research is needed to disentangle the temporal sequence and identify potential interventions to prevent declines in function.