LAUSR

Purpose This prospectively designed study aimed to investigate the association between sleep duration and overweight in a cohort of Chinese adolescents. Methods A school-based cohort study with a 2-year follow-up was conducted among Chinese adolescents in Ningbo region (China). For the baseline study, 1901 school-aged Chinese children aged 12–13 years were recruited. Finally, 1510 adolescents were successfully reinterviewed in October 2018. Participants were asked to complete a self-administered questionnaire, and their heights and weights were directly measured. Results Overweight adolescents had shorter sleep duration or later bedtimes than non-overweight children in baseline ( P  < 0.05). In the multivariable linear regression analysis, sleep duration was marginally significantly correlated with body mass index (BMI) at baseline and significantly correlated with this parameter at a 2-year follow-up ( β  = − 0.23, 95% confidence interval (CI): − 0.51 to 0.04, P  < 0.1; β  = − 0.27, 95% CI: − 0.42 to − 0.11, P  < 0.05, respectively). After adjusting for potential confounders, the multivariable logistic regression analysis revealed associations of a longer sleep duration at baseline with a reduced likelihood of participants being overweight both at baseline and at follow-up (adjusted odds ratio ( AOR ) = 0.81, 95% CI: 0.66 to 1.00, P  = 0.05; AOR  = 0.43, 95% CI:0.24 to 0.76, P  < 0.05, respectively). Conclusions Shorter sleep was associated with an increased likelihood of being overweight in Chinese adolescents, while a 1-h decrease in sleep per night led to a more than 50% increase in the overweight risk at the 2-year follow-up.