0001 Circadian Rest-Activity Rhythm Patterns and Physical Performance in Community-Dwelling Older Men

Abstract Introduction Circadian rest-activity rhythms (RARs), a behavioral manifestation of circadian rhythms, reflect physical activity and sleep patterns over the 24-hour day. With aging, disrupted RARs may be associated with higher cardiometabolic risk, fall risk and cognitive decline. Physical performance also declines with advancing age, leading to disability and increased risk of mortality. However, the associations between RARs and physical performance are understudied. Methods In the Osteoporotic Fractures in Men (MrOS) study, 2,924 men (age=76.3+/-5.5 years, 90% white) completed sleep ancillary study (baseline), had valid wrist-worn actigraphy data (mean=5 days) and physical performance measures. Physical performance measures included: 6-meter gait speed, grip strength, and chair stand pace assessed at baseline and up to two follow-up visits over 3.4+/-3.1 years. Using a shape-naive technique, functional principal components analysis (fPCA), we examined baseline patterns of RARs over several days and evaluated cross-sectional and longitudinal associations of these patterns with each physical performance measure separately using mixed effect models. Models were adjusted for age, race, education, body mass index, smoking, alcohol use, caffeine consumption, multimorbidity, medication use and depressive symptomology. Results At baseline, gait speed was 1.14+/-0.23 m/s, grip strength was 40.8+/-8.4 kg, and chair stand pace was 4.4+/-1.7 stands/10 sec. Four fPCA components (explaining 88% variance) were identified with higher eigenvalues meaning: 1) high overall amplitude (50%); 2) later rise and bed times (23%); 3) longer, biphasic activity patterns (9%); and 4) evening peaks in activity (6%). Cross-sectionally, higher fPCA1 was associated with faster gait speed and chair stand pace (p< 0.05); higher fPCA3 was associated with slower gait speed, worse grip strength, and slower chair stand pace (p< 0.05). Longitudinally, higher fPCA1 was associated slower decline in gait speed and in chair stand pace (p< 0.05); higher fPCA2 was associated with accelerated decline in chair stand pace (p< 0.05); higher fPCA3 and fPCA4 were both associated with accelerated decline in gait speed (p< 0.05). No longitudinal association was found with grip strength. Conclusion Specific disruptions in RARs are associated with poor physical performance and its subsequent decline in older men. It suggests the contribution of circadian system in influencing age-related physical performance. Support (if any) NIA R21AG051380 and R01AG034157