title: Socio-Demographic, Social-Cognitive, Health-Related and Physical Environmental Variables Associated with Context-Specific Sitting Time in Belgian Adolescents: A One-Year Follow-Up Study.
abstract: BACKGROUND
  More knowledge is warranted about multilevel ecological variables associated with context-specific sitting time among adolescents. The present study explored cross-sectional and longitudinal associations of ecological domains of sedentary behaviour, including socio-demographic, social-cognitive, health-related and physical-environmental variables with sitting during TV viewing, computer use, electronic gaming and motorized transport among adolescents.
  
  
  METHODS
  For this longitudinal study, a sample of Belgian adolescents completed questionnaires at school on context-specific sitting time and associated ecological variables. At baseline, complete data were gathered from 513 adolescents (15.0±1.7 years). At one-year follow-up, complete data of 340 participants were available (retention rate: 66.3%). Multilevel linear regression analyses were conducted to explore cross-sectional correlates (baseline variables) and longitudinal predictors (change scores variables) of context-specific sitting time.
  
  
  RESULTS
  Social-cognitive correlates/predictors were most frequently associated with context-specific sitting time. Longitudinal analyses revealed that increases over time in considering it pleasant to watch TV (p < .001), in perceiving TV watching as a way to relax (p < .05), in TV time of parents/care givers (p < .01) and in TV time of siblings (p < .001) were associated with more sitting during TV viewing at follow-up. Increases over time in considering it pleasant to use a computer in leisure time (p < .01) and in the computer time of siblings (p < .001) were associated with more sitting during computer use at follow-up. None of the changes in potential predictors were significantly related to changes in sitting during motorized transport or during electronic gaming.
  
  
  CONCLUSIONS
  Future intervention studies aiming to decrease TV viewing and computer use should acknowledge the importance of the behaviour of siblings and the pleasure adolescents experience during these screen-related behaviours. In addition, more time parents or care givers spent sitting may lead to more sitting during TV viewing of the adolescents, so that a family-based approach may be preferable for interventions. Experimental study designs are warranted to confirm the present findings.
authors.affiliation: Department Movement & Sport Sciences, Ghent University, Ghent, Belgium.|Research Foundation Flanders (FWO), Brussels, Belgium.
authors.forename: Cedric
authors.initials: C
authors.lastname: Busschaert
authors.affiliation: Centre for Physical Activity and Nutrition Research, Deakin University, Burwood Melbourne, Australia.
authors.forename: Nicola D
authors.initials: ND
authors.lastname: Ridgers
authors.affiliation: Department Movement & Sport Sciences, Ghent University, Ghent, Belgium.
authors.forename: Ilse
authors.initials: I
authors.lastname: De Bourdeaudhuij
authors.affiliation: Department Movement & Sport Sciences, Ghent University, Ghent, Belgium.
authors.forename: Greet
authors.initials: G
authors.lastname: Cardon
authors.affiliation: Research Foundation Flanders (FWO), Brussels, Belgium.|Department Public Health, Ghent University, Ghent, Belgium.|Department of Human Biometry and Biomechanics, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Jelle
authors.initials: J
authors.lastname: Van Cauwenberg
authors.affiliation: Department Movement & Sport Sciences, Ghent University, Ghent, Belgium.|Research Foundation Flanders (FWO), Brussels, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: De Cocker
mesh_terms: D000293:Adolescent; D001290:Attitude; D001530:Belgium; D003201:Computers; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007899:Leisure Activities; D008137:Longitudinal Studies; D008297:Male; D057181:Pleasure; D057185:Sedentary Behavior; D035781:Siblings; D012959:Socioeconomic Factors; D013690:Television; D014186:Transportation; D018910:Video Games