title: Dose-response association of screen time-based sedentary behaviour in children and adolescents and depression: a meta-analysis of observational studies.
abstract: BACKGROUND
  Depression represents a growing public health burden. Understanding how screen time (ST) in juveniles may be associated with risk of depression is critical for the development of prevention and intervention strategies. Findings from studies addressing this question thus far have been inconsistent. Therefore, we conducted a comprehensive systematic review and meta-analysis of data related to this question.
  
  
  METHODS
  The meta-analysis was conducted in accordance with the PRISMA guideline. We searched the electronic databases of PubMed, Web of Science and EBSCO systematically (up to 6 May 2015). OR was adopted as the pooled measurement of association between ST and depression risk. Dose-response was estimated by a generalised least squares trend estimation.
  
  
  RESULTS
  Twelve cross-sectional studies and four longitudinal studies (including 1 cohort study) involving a total of 127 714 participants were included. Overall, higher ST in preadolescent children and adolescents was significantly associated with a higher risk of depression (OR=1.12; 95% CI 1.03 to 1.22). Screen type, age, population and reference category acted as significant moderators. Compared with the reference group who had no ST, there was a non-linear dose-response association of ST with a decreasing risk of depression at ST<2 h/day, with the lowest risk being observed for 1 h/day (OR=0.88; 95% CI 0.84 to 0.93).
  
  
  CONCLUSIONS
  Our meta-analysis suggests that ST in children and adolescents is associated with depression risk in a non-linear dose-response manner.
authors.affiliation: Medical Psychological Institute, Second Xiangya Hospital of Central South University, Changsha, Hunan, China School of Education, Hunan University of Science and Technology, Xiangtan, Hunan, China.
authors.forename: Mingli
authors.initials: M
authors.lastname: Liu
authors.affiliation: Center for Clinical and Translational Science, Mayo Clinic, Rochester, Minnesota, USA Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
authors.forename: Lang
authors.initials: L
authors.lastname: Wu
authors.affiliation: Medical Psychological Institute, Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
authors.forename: Shuqiao
authors.initials: S
authors.lastname: Yao
mesh_terms: D000293:Adolescent; D002648:Child; D003201:Computers; D003863:Depression / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D064887:Observational Studies as Topic; D012307:Risk Factors; D057185:Sedentary Behavior; D013690:Television; D013997:Time Factors; D018910:Video Games
keywords: Adolescent; Depression; Physical activity; Psychology; Sedentary