Association between sleep and physical function in older men: The osteoporotic fractures in men sleep study

OBJECTIVES: To determine whether sleep quality is associated with physical function in older men. DESIGN: Cross-sectional. SETTING: Six U.S. centers. PARTICIPANTS: Two thousand eight hundred sixty-two community-dwelling men. MEASUREMENTS: Total hours of nighttime sleep (TST), wake after sleep onset (WASO), sleep latency (SL), and sleep efficiency (SE) measured using actigraphy; sleep stage distribution, respiratory disturbance index (RDI), and hypoxia measured using polysomnography; measures of physical function: grip strength, walking speed, chair stand, and narrow walk. RESULTS: In age-adjusted models, < 6 or > 8 hours TST, SE less than 80%, WASO of 90 minutes or longer, RDI of 30 or greater, and hypoxia were associated with poorer physical function. (Mean grip strength was 2.9% lower and mean walking speed was 4.3% lower in men with WASO >= 90 minutes than men with WASO < 90 minutes.) After adjusting for potential covariates, differences in grip strength and walking speed remained significantly associated with WASO of 90 minutes or longer, SE less than 80%, and hypoxia but not with TST or RDI of 30 or greater. CONCLUSION: Greater sleep fragmentation and hypoxia are associated with poorer physical function in older men.