title: Associations between physical inactivity and sedentary behaviors among adolescents in 10 cities in China.
abstract: BACKGROUND
  Studies in western countries have revealed that excessive sedentary behavior is a major risk factor for physical inactivity in adolescents. This study was performed to investigate the association between sedentary behavior and physical inactivity in Chinese adolescents using a large-scale cross-sectional survey design.
  
  
  METHODS
  This study was part of the 2011 Chinese Youth Risk Behavior Survey. Between March and September 2011, 10,214 11-18-year-olds were recruited for survey participation in 18 schools in 10 cities in China. Demographic and socioeconomic characteristics, and the prevalences of physical inactivity and sedentary behaviors, were examined. Correlations between sedentary behavior and physical inactivity were analyzed using baseline logistic regression.
  
  
  RESULTS
  Among the final 9,901 students, physical inactivity (~80%) and sedentary behaviors (television viewing, 43%; computer use, 30.2%) were prevalent. More male than female students reported sedentary behaviors (television viewing > 2 h: 5.5% vs. 3.9%; computer use > 2 h: 7.2% vs. 3.5%; both p < 0.05), but more males were physically active than females (25.1% vs.14.6%; p < 0.05). Television viewing was associated with lower odds of no physical activity (No PA) in males [0-2 h: adjusted odds ratio (AOR) = 0.81, 95% confidence interval (CI) = 0.68-0.96; >4 h: OR = 0.34, 95% CI = 0.18-0.64], but not in females. A similar pattern between insufficient physical activity and >4 h TV viewing (AOR = 0.42, 95% CI = 0.23-0.76) and >4 h computer use (AOR = 0.49, 95% CI = 0.30-0.78) was observed in males. In females, 0-2 h daily computer use was associated with higher odds of physical inactivity (No PA: AOR = 1.42, 95% CI = 1.10-1.82; Insufficient PA: AOR = 1.58, 95% CI = 1.24-2.01), while TV viewing was not associated with No PA or Insufficient PA. The probability of physical inactivity significantly increased with grade and decreased with socioeconomic status.
  
  
  CONCLUSIONS
  Physical inactivity and sedentary behaviors were prevalent in Chinese adolescents. Further support, including parental guidance and the provision of publicly accessible facilities, is necessary to encourage Chinese youths to engage sufficiently in physical activities.
authors: You
authors: Y
authors: Chen
authors: Zhonghui
authors: Z
authors: Zheng
authors: Medical Psychological Institute, Second Xiangya Hospital, Central South University, #139 Ren-Min Zhong Road, Changsha 410011, China. jinyaoyi@gmail.com.
authors: Jinyao
authors: J
authors: Yi
authors: Shuqiao
authors: S
authors: Yao
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D002648:Child; D002681:China; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006306:Health Surveys / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D016017:Odds Ratio; D012307:Risk Factors; D057185:Sedentary Behavior; D017678:Sex Distribution; D014505:Urban Population / Q000706:statistics & numerical data*