title: Screen time, physical activity and mental health among urban adolescents in China.
abstract: OBJECTIVE
  To test the association between screen time (ST), physical activity (PA) and self-reported psychological problems among urban adolescents aged 11 to 16 years.
  
  
  METHODS
  In 2010, total 5003 boys and girls were analyzed from 4 junior high schools in Bengbu city of China. The Depression Self-rating Scale for Children, Screen for Child Anxiety Related Emotional Disorders and School Life Satisfaction Rating Questionnaire were administered to obtain information on current mental health. Self-reported ST, PA and dietary intake were also assessed. Logistic regression analyses were used to explore the effects of ST and PA on psychological problems.
  
  
  RESULTS
  Approximately 26.1% of adolescents were exposed to ST for more than 2h/day. High ST was a risk factor for depressive symptoms (odds ratio (OR)=1.52, 95% confidence interval (CI): 1.31-1.76), anxiety symptoms (OR=1.36, 95%CI: 1.18-1.57) and school life dissatisfaction (OR=2.07, 95%CI: 1.79-2.38). Sufficient vigorous PA (VPA) was a protective factor for depressive symptoms (OR=0.78, 95%CI: 0.67-0.91) and school life dissatisfaction (OR=0.73, 95%CI: 0.62-0.85). The combination of high ST and insufficient VPA was associated with the highest prevalence of various psychological problems.
  
  
  CONCLUSIONS
  High ST and insufficient VPA interact to increase depressive, anxiety symptoms and school life dissatisfaction among Chinese adolescents.
authors.affiliation: Department of Maternal, Child and Adolescent Health, Anhui Medical University, Anhui, China. caohui1230@126.com
authors.forename: Hui
authors.initials: H
authors.lastname: Cao
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Qian
authors.forename: Tingting
authors.initials: T
authors.lastname: Weng
authors.forename: Changjiang
authors.initials: C
authors.lastname: Yuan
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Fangbiao
authors.initials: F
authors.lastname: Tao
mesh_terms: D000293:Adolescent; D001007:Anxiety / Q000453:epidemiology*; D002648:Child; D002681:China / Q000453:epidemiology; D003201:Computers; D015986:Confounding Factors, Epidemiologic; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008603:Mental Health; D010549:Personal Satisfaction; D012574:Schools; D057566:Self Report; D013690:Television; D013997:Time Factors; D014505:Urban Population