Independent and joint associations of sleep and 24-Hour rest-activity rhythms with reduced kidney function in older adults.

BACKGROUND: This study aimed to investigate the independent and joint associations of sleep and 24-hour rest-activity rhythms with reduced kidney function among older adults in rural China. METHODS: Data from 1493 participants in the baseline survey of the Rural Physical Activity Behavior and Healthy Aging Cohort were analyzed. Sleep and 24-hour rest-activity rhythm parameters, including total sleep time (TST), wakefulness after sleep onset (WASO), interdaily stability (IS), intradaily variability (IV), Least active 5 h span (L5), Most active 10 h span (M10), and relative amplitude (RA). Multivariable logistic regression models were employed to examine the independent and joint associations of sleep and 24-hour rest-activity rhythms with reduced kidney function. RESULTS: Independent analyses revealed that IS, L5, and M10 were significantly inversely associated with reduced kidney function (IS: OR = 0.13, 95% CI: 0.04-0.49; L5: OR = 0.89, 95% CI: 0.82-0.97; M10: OR = 0.97, 95% CI: 0.96-0.99), whereas IV and TST were significantly positively associated with reduced kidney function (IV: OR = 2.90, 95% CI: 1.37-6.15; TST: OR = 1.35, 95% CI: 1.15-1.57). Joint analyses demonstrated that compared with the long sleep group, the moderate and short sleep groups exhibited significantly lower ORs. Regardless of sleep duration, the stable rest-activity rhythm group showed significantly lower ORs than the unstable group. CONCLUSION: These findings suggest that maintaining stability in rest-activity rhythms should be emphasized in older rural Chinese populations, as it may play an important role in the early prevention and management of reduced kidney function.