title: Physical activity, sedentary behavior, and depressive symptoms among adolescents.
abstract: BACKGROUND
  This study examined cross-sectional and longitudinal associations between physical activity, sedentary behavior, and depressive symptoms among adolescents.
  
  
  METHODS
  Participants were 155 adolescents (14.4 years±0.61) in 2004 (40% boys). Data collection occurred in 2004 and again in 2006. At both time points, participants completed the Centers for Epidemiological Studies Depression Scale for Children (CES-DC), from which they were classified as having depressive symptoms (≥15) or not (<15). Organized sport and TV viewing were self-reported and moderate-to-vigorous (MVPA) and vigorous (VPA) physical activity and sedentary time were objectively measured. Logistic and linear regression analyses examined cross-sectional and longitudinal associations between MVPA, VPA, organized sport, TV viewing, sedentary time, and symptoms of depression.
  
  
  RESULTS
  There were no cross-sectional or longitudinal associations between MVPA, VPA, organized sport, sedentary time, and symptoms of depression among boys or girls. However, having symptoms of depression in 2004 did predict higher TV viewing among adolescent girls in 2006 (approximately 168 minutes/week more TV viewing; P≤.001).
  
  
  CONCLUSIONS
  MVPA, VPA, organized sport and objectively-measured sedentary time appeared unrelated to depressive symptoms in this sample, but depressive symptoms predicted increased TV viewing over time among adolescent girls. Further research is required to determine the clinical relevance of this finding.
authors.affiliation: Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia.
authors.forename: Clare
authors.initials: C
authors.lastname: Hume
authors.forename: Anna
authors.initials: A
authors.lastname: Timperio
authors.forename: Jenny
authors.initials: J
authors.lastname: Veitch
authors.forename: Jo
authors.initials: J
authors.lastname: Salmon
authors.forename: David
authors.initials: D
authors.lastname: Crawford
authors.forename: Kylie
authors.initials: K
authors.lastname: Ball
mesh_terms: D000293:Adolescent; D001835:Body Weight; D003430:Cross-Sectional Studies; D003863:Depression / Q000523:psychology*; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D017678:Sex Distribution; D012959:Socioeconomic Factors; D013177:Sports / Q000706:statistics & numerical data; D013690:Television / Q000706:statistics & numerical data*