Association Between Outdoor Activity and Insufficient Sleep in Chinese School-Aged Children

Background: The aim of this study was to explore the relationship between outdoor activity (OA) and insufficient sleep duration (ISD) among Chinese children and to assess the potential age- and gender-specific effects. Material/Methods: A national sample of 62 517 children aged 6-17 years were recruited from 7 provinces of China in the autumn of 2013. Children and their caregivers reported daily sleep duration (<7 h, 7-9 h and >= 9 h), daily OA time (<1 h, 1-2 h, and >= 2 h), and other behavior and demographic information by standardized questionnaire. ISD was defined as <9 h/day. Logistic regression analysis was used to evaluate the relationship between ISD and OA. Results: In total, 46 639 children (50.9% boys) completed this survey. The prevalence of ISD was 74.9% (73.7% in boys and 76.1% in girls). Stratified by age, compared with <1 h OA, the odds ratios for ISD were 0.67 (95% confidence interval: 0.62-0.72, aged 6-13 years) and 0.69 (0.49-0.98, 14-17 years) in the >= 2 h OA group; 0.91 (0.85-0.97, 6-13 years) and 0.73 (0.54-0.97, 14-17 years) in the 1-2 h OA group. Further stratified by gender, we found similar trends for both boys and girls in each age group, although some results became non-significant. Conclusions: Adequate OA time per day is associated with decreased risks for ISD among children aged 6-17 years, but age and gender can modify the association.