Physical activity and associated socio-demographic factors among school adolescents in Jiangsu Province, China

BACKGROUND: Obesity prevalence is increasing among adolescents in China, especially in urban areas and among higher socio-economic strata. Physical inactivity may be one of the causes. We examined socio-demographic differences in physical activity among school adolescents in Jiangsu Province. METHODS: In 2002, 824 adolescents (12-14 years) in 8 schools filled in a self administered questionnaire on physical activity, sedentary behaviors and socio-demographic characteristics. RESULTS.: In girls, low SES elicited the highest physical activity score, mainly derived from housework. More boys (49.1%) than girls (41%) had vigorous physical activity (VPA) >or=3 times/week. Associations between VPA and residence, age, SES were not significant. 88% of the adolescents were actively commuting to schools. Boys with high SES or high education fathers had the lowest percentage walking to school. The students spent daily on average 10.8 h on studying, however, little time was spent on watching TV or playing PC games. CONCLUSIONS: Active commuting to school was common among the adolescents. However, the sedentary activity level is high. Physical activity was negatively associated with SES.