Nutrition and physical activity related school environment/policy factors and child obesity in China: a nationally representative study of 8573 students in 110 middle schools

BackgroundObesity is a serious threat to global health. School is a key setting for obesity intervention. Research on school risk factors for child obesity is limited in developing countries. ObjectivesTo examine regional variations in obesity and school environments/policies and their associations among students in China. MethodsAnalyses were based on the first nationally representative sample of 8573 9(th) graders in 110 middle schools from 28 regions across China. Multilevel models tested associations between school factors and child self-reported weight outcomes and by school urbanicity setting (urban, rural). ResultsOverweight/obesity rate is higher among boys and in urban areas. Schools in rural areas, or less developed regions, promote longer on-campus life, as is indicated by the presence of school cafeterias, night study sessions and longer class hours. Multilevel models show that (i) school cafeterias (OR=2.53, 95% CI=1.35-4.75) and internet bars close to school (OR=1.63, 95% CI=1.15-2.30) are associated with increased overweight/obesity risk in rural areas, especially for boys; (ii) school night study sessions are associated with lower overweight/obesity risk (OR=0.69, 95% CI=0.50-0.96) in rural areas. ConclusionsChina has large regional disparities in school environment/policies related to nutrition and physical activity. Some school factors are associated with students' weight status, which vary across gender and areas. Future school-based interventions should attend to diverse regional contexts.