Objectives: To investigate the prospective relationship between alcohol consumption and incident mobility limitation.
Design: Cohort study.
Setting: The Health Aging and Body Composition study, conducted in Memphis, Tennessee, and Pittsburgh, Pennsylvania.
Participants: Three thousand sixty-one adults aged 70 to 79 without mobility disability at baseline.
Measurements: Incidence of mobility limitation, defined as self-report at two consecutive semiannual interviews of any difficulty walking one-quarter of a mile or climbing stairs, and incidence of mobility disability, defined as severe difficulty or inability to perform these tasks at two consecutive reports. Alcohol intake, lifestyle-related variables, diseases, and health status indicators were assessed at baseline.
Results: During a follow-up time of 6.5 years, participants consuming moderate levels of alcohol had the lowest incidence of mobility limitation (total: 6.4 per 100 person-years (person-years); men: 6.4 per 100 person-years; women: 7.3 per 100 person-years) and mobility disability (total: 2.7 per 100 person-years; men: 2.5 per 100 person-years; women: 2.9 per 100 person-years). Adjusting for demographic characteristics, moderate alcohol intake was associated with lower risk of mobility limitation (hazard ratio (HR)=0.70, 95% confidence interval (CI)=0.55-0.89) and mobility disability (HR=0.66, 95% CI=0.45-0.95) than never or occasional consumption. Additional adjustment for lifestyle-related variables substantially reduced the strength of the associations (HR=0.85, 95% CI=0.66-1.08 and HR=0.81, 95% CI=0.56-1.18, respectively). Adjustment for diseases and health status indicators did not affect the strength of the associations, suggesting that lifestyle is most important in confounding this relationship.
Conclusion: Lifestyle-related characteristics mainly accounted for the association between moderate alcohol intake and lower risk of functional decline over time. These findings do not support a direct causal effect of alcohol intake on physical function.