Association of Longitudinal Patterns of Nighttime Sleep Duration and Daytime Napping Duration with Risk of Multimorbidity

Background: Single measures of self-reported nighttime sleep duration and daytime napping duration are associated with adverse health outcomes; However, the association between longitudinal patterns of self-reported nighttime sleep duration and daytime napping duration and multimorbidity remains unclear. We therefore undertook cox regression analyses to explore linkages between sleep trajectories and multimorbidity. Methods: : The current study included 5262 participants from China Health and Retirement Longitudinal Study. Self-reported nighttime sleep duration and daytime napping duration were collected from 2011 to 2015. The 4-year sleep duration trajectories were conducted by group-based trajectory modelling. The fourteen medical conditions were diagnosed by self-reported physicians or identified by combining health assessment and medication data. Multimorbidity was diagnosed as Participants with two or more of the 14 chronic diseases after 2015. Associations between sleep trajectories and multimorbidity were assessed by cox regression models. Results: : During 6.69 years of follow-up, we observed multimorbidity in 785 participants. Four nighttime sleep duration trajectories and three daytime napping duration trajectories were identified. Participants with persistent short nighttime sleep duration trajectory had the higher risk of multimorbidity (Hazard ratio (HR)=1.24, 95% confidence interval (CI): 1.04-1.49), compared with those with persistent normal nighttime sleep duration trajectory. We have not found a benefit of daytime napping on the development of multimorbidity. Participants with persistent normal nighttime sleep duration and persistent seldom daytime napping duration had a lower risk of multimorbidity. Conclusions: : In this study, persistent short nighttime sleep duration trajectory was associated with subsequent multimorbidity risk. Daytime napping cannot fully compensate for the risk of insufficient night sleep.