LAUSR

Objectives The prevalence of overweight among Chinese children and adolescent increased steadily in the past two decades. Few studies exist even on long-term trends in physical activity in children or adolescents and very few long-term longitudinal studies have examined the association between physical activity or sedentary activity and the risk of overweight and obesity globally. Methods We used longitudinal data of the China Health and Nutrition Survey from 2004 to 2015 to examine the relationship among 4520 children and adolescents aged 6-18 years old. We collected detailed seven-day data on physical activity and sedentary activity, including sports and exercise, commute mode, household chores, screen time, homework, and other activities and converted them into metabolic equivalents (MET) values. We used the hybrid approach on the random-effects models to estimate the association between physical activity, sedentary activity and the risk of overweight and obesity. Results The child and adolescent prevalence of overweight and obesity increased from 5.8% in 2004 to 16.5% in 2015, while physical activity decreased from 60.9 to 49.1 METs hour/week and sedentary activity increased from 26.9 to 22.9 hours/week during the same period. Controlled for age, gender, urbanization index, income, energy intake, mother's BMI and education, and survey year, the results showed that physical activity significantly decreased the risk of overweight and obesity among girls [for 6-11 years old girls, OR = 0.37(95% CI 0.20 - 0.67); for 12-18 years old girls, OR = 0.46 (95% CI: 0.25 - 0.85)]. Sedentary activity significantly increased the risk of overweight and obesity among older girls only [OR = 1.96 (95% CI: 1.09 - 3.54)]. The association was not significant among boys. Conclusions Low physical activity and high sedentary activity increased the risk of overweight and obesity among Chinese girls, particularly teenage girls. More studies are needed among boys. Funding Sources The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH; The Fogarty International Center, NIH; Department of Nutrition & Carolina Population Center, The University of North Carolina at Chapel Hill; Chinese Center for Disease Control and Prevention.