Abstract: Objective To understand the prevalence of overweight/obesity among Chinese adults,and to explore the relationship between nap duration,nighttime sleep duration and overweight/obesity. Methods Data were collected from the 2020 China Family Panel Studies （CFPS） database. Frequency and percentage were used to conduct general statistical description of overweight and obesity. Binary logistic regression and restricted cubic spline were used to explore the relationship and nonlinear relationship between nap duration,nighttime sleep duration and overweight/obesity in adults. Results A valid sample of 20 955 individuals was included in this study,and the rates of overweight/obesity,napping habit,and insufficient nighttime sleep were 38.8% （8 137/20 955）,61.1% （12 806/20 955）,and 20.4% （4 279/20 955）,respectively. After controlling for confounders,nap duration 30~<60 min （OR=1.105）,60~<90 min （OR=1.143）,and ≥90 min （OR=1.207） was associated with overweight/obesity compared with no napping. Compared with nighttime sleep duration of 7-9 h,nighttime sleep duration<7 h was associated with overweight/obesity （OR=1.168）. The results of the restricted cubic spline showed that 30 min of nap duration and 8 h of nighttime sleep duration were the critical points,nap duration >30 min and nighttime sleep duration <8 h were associated with an increased risk of overweight and obesity. The results of gender stratification showed that the nap duration 30~<60 min （OR=1.256） and ≥90 min （OR=1.146） were associated with overweight/obesity in men,and the nap duration 60~<90 min （OR=1.204） and ≥90 min （OR=1.346） were associated with overweight/obesity in women. Nighttime sleep duration<7 h was associated with overweight and obesity in men （OR=1.155） and women （OR=1.166）. There was an interaction between gender and nap duration 30~<60 min,60~<90 min,≥90 min,and nighttime sleep duration<7 h （P<0.05 or P<0.01）. Conclusion Prolonged nap duration and insufficient nighttime sleep duration were closely associated with overweight/obesity in adults,and the effect of nap duration on overweight/obesity in adults needs further study.

Key words: Overweight, Obesity, Nap duration, Nighttime sleep duration