Sleep Duration and Overweight/Obesity in Preschool-Aged Children: A Prospective Study of up to 48,922 Children of the Jiaxing Birth Cohort

Study Objectives: To examine the association between sleep duration and overweight/obesity in preschool-aged children. Methods: A total of 48,922 3-year old children enrolled in the Jiaxing Birth Cohort, who provided sleep information and anthropometric data, were included in the present study as baseline and were followed up to 5 years of age. Sleep duration was categorized as <= 10 hours, 11-12 hours, and >= 13 hours. Overweight and obesity were defined according to the cut point criteria in China. Prevalence ratios and risk ratios were used to assess the association between sleep duration and risk of overweight/obesity. Results: In cross-sectional analyses at baseline, the adjusted prevalence ratios (95% confidence interval) of overweight (with 11-12 h of sleep being considered the reference group) for children sleeping <= 10 h and >= 13 h were 1.13 (1.06-1.20) and 1.16 (1.09-1.24), respectively, whereas the adjusted prevalence ratios (95% confidence interval) of obesity were 1.25 (1.11-1.40) and 1.25 (1.11-1.42). In longitudinal analyses, the adjusted risk ratios (95% confidence interval) of overweight for children sleeping <= 10 h and >= 13 h were 1.48 (1.26-1.74) and 1.13 (0.96-1.34), while adjusted risk ratios (95% confidence interval) of obesity were 1.77 (1.30-2.40) and 1.19 (0.85-1.66). Restricted cubic splines regression supported U-shaped curvilinear associations between sleep duration and overweight/obesity in both cross-sectional and longitudinal analyses. Conclusions: Both short and overlong sleep duration are associated with a higher risk of overweight/obesity in preschool-aged children. Optimizing sleep duration may be an important modifiable intervention for overweight and obesity.