The associations of daytime napping and motoric cognitive risk syndrome: Findings from the China Health and Retirement Longitudinal Study

Introduction: Motoric cognitive risk syndrome (MCR), characterized by subjective cognitive complaints and slow gait in older populations, is associated with sleep duration. However, the association between MCR and daytime nap duration has not been thoroughly explored. Methods: Baseline data from the China Health and Retirement Longitudinal Study (CHARLS) were used in this study. MCR was defined as the coexistence of subjective cognitive complaints and objective slow gait speed without a history of dementia or mobility disability. Daytime nap duration was categorized into four groups: no napping, short napping ( <30 min), moderate napping (30 -89 min) and extended napping ( >= 90 min). Multivariable logistic regression models were used to explore the association of daytime napping duration and MCR. Results: A total of 4230 individuals aged >= 60 were included in the current analysis, of which 463 were diagnosed with MCR. Moderate napping of 30 -89 min per day was found to be significantly associated with lower odds of MCR compared with the reference group of no napping. In subgroup analysis, individuals with sleep durations of <7 h per night had lower odds of MCR in the model that adjusted for all potential confounders with >= 30 min daytime nap duration compared with no napping. Interestingly, for people with a night sleep duration of 7 -8 h, only those with a moderate nap of 30 -89 min had lower odds of MCR than non -nappers after adjustment for potential confounders. Conclusion: A moderate nap of 30 -89 min could lower the odds of MCR, especially for older adults with a night sleep duration of <= 8 h.