Gender-dependent association between sleep duration and overweight incidence in CHINESE school children: a national follow-up study

Background: The relationship between sleep duration and overweight risk remains unexplored among Chinese children. This study aims to evaluate this association in a national investigation with school-aged population. Methods: There were 18,302 normal weight children in this Chinese national study which conducted during 2013-2014 included in the research. Anthropometric measurements were performed both at baseline and after 6-9 month. Sleep duration, physical activity, food intake and social economic information were collected by self-report questionnaire. Overweight was defined according to the updated Chinese criterion. Cox regression was used to evaluate the relationships between sleep duration and overweight incidence with multivariable adjusted. Results: In total, there were 443 new overweight cases recorded at the end of observation. Overweight incidence with greater than 9 h (long sleep duration, LSD), 7 to 9 h (middle sleep duration, MSD), and less than 7 h of sleep (short sleep duration, SSD) were 2.7, 3.1 and 3.3% respectively. Stratified by gender and compared with LSD, the hazard ratio (HR) of overweight for females with MSD was 1.60 (95% CI: 1.02-2.52). Stratified by age and gender, the HR in the group of MSD was 2.13 (1.20-3.77) in female aged 6-10 years and 0.24 (0.06-0.93) in female aged 15-17 years. Conclusion: The association between short sleep duration and overweight is age- and gender dependent. In group of small age and elder age, girls' adiposity states are independently associated with sleep duration. Sleep recommendation is a potential preventive action for overweight/obesity among girls.