Physical activity and sedentary behaviors among Chinese children: recent trends and correlates

Background With the progress of urbanization and technology advancement in China, this study aimed to examine the trends in and correlates of PA and sedentary behaviors among Chinese children. Methods Self-reported physical activity data were extracted from the “China Health and Nutrition Survey” project. A total of 6,936 observations (4341 subjects) aged 6–17 years old who participated in at least one round of follow-up surveys from 2004 to 2015 were included. Random-effects ordinal regression models were applied to investigate the trends in the levels of PA, and repeated measures mixed models were applied to examine the trends in and distribution characteristics of PA and sedentary behaviors, controlling for the random effect of communities and adjusting for socio-demographic differences. Quantile regression models were applied to explore the influencing factors at each quartile of PA volume and time spent in sedentary behaviors. Results The prevalence of physical inactivity among Chinese Children aged 6–17 years increased from 76.0% in 2004 to 81.5% in 2015 (OR = 1.51, 95% CI: 1.19 ~ 1.90, p < 0.001). The average weekly volume of PA declined from 41.7 ± 1.6 to 35.9 ± 1.7 MET-hrs/week (P < 0.001) from 2004 to 2015, of which, in-school PA declined significantly by 4.6 MET-hrs/week (P < 0.001). The time spent in sedentary behaviors rose from 23.9 ± 0.6 hrs/week in 2004 to 25.7 ± 0.6 hrs/week in 2015 (p < 0.001), with more profound increases observed for the time on screen-based entertainment (increased by 2.9 hrs/week, P < 0.001). Age, ethnicity, and region showed significant effects on the volume of PA across quartiles (p < 0.001). Compared with children residing in rural area or with low urbanization level, sedentary time was significantly higher than those residing in urban areas (p < 0.001) or with high urbanization level (p ≤ 0.005) across quartiles. Conclusions To improve PA and curb sedentary behaviors among Chinese children aged 6–17 years old, urgent actions should be taken to promote in-school PA and to reduce their screen time. The findings also suggest certain subgroups and geographical areas that are at higher risk of physical inactivity, which warrants more attention when designing and implementing physical activity-promoting policy and action.