Circadian syndrome and mortality risk in adults aged ≥ 40 years: a prospective cohort analysis of CHARLS and NHANES.

Circadian rhythm disruption is increasingly prevalent and associated with higher morbidity and mortality. This study investigates the relationship between Circadian Rhythm Syndrome (CircS) and mortality in middle-aged and older adults. This prospective cohort study utilized mortality follow-up data from the China Health and Retirement Longitudinal Study (CHARLS) and the National Health and Nutrition Examination Survey (NHANES). Cox proportional hazards models examined the association between CircS and all-cause mortality, while restricted cubic spline analysis explored non-linear relationships. Subgroup analyses investigated potential modifying factors. Cox models and Bayesian generalized linear models were used to explore relationships between CircS and specific causes of death. The study included 7,637 participants from CHARLS (2011-2020) and 9,320 participants from NHANES (2005-2018), with 142 and 1,321 all-cause deaths. The follow-up periods were 9.17 years for CHARLS and 15 years for NHANES. CircS was significantly associated with increased all-cause mortality risk (CHARLS: HR 1.79, 95% CI: 1.23-2.62; NHANES: HR 1.21, 95% CI: 1.03-1.42). A linear dose-response relationship was observed between the number of CircS components and mortality risk. CircS was positively associated with mortality from diabetes, cardiovascular, cerebrovascular, and kidney-related diseases. CircS is strongly associated with increased mortality risk. These findings underscore the importance of addressing circadian disruptions in public health strategies.