title: TV viewing and physical activity are independently associated with metabolic risk in children: the European Youth Heart Study.
abstract: BACKGROUND
  TV viewing has been linked to metabolic-risk factors in youth. However, it is unclear whether this association is independent of physical activity (PA) and obesity.
  
  
  RESULTS
  We did a population-based, cross-sectional study in 9- to 10-y-old and 15- to 16-y-old boys and girls from three regions in Europe (n = 1,921). We examined the independent associations between TV viewing, PA measured by accelerometry, and metabolic-risk factors (body fatness, blood pressure, fasting triglycerides, inverted high-density lipoprotein (HDL) cholesterol, glucose, and insulin levels). Clustered metabolic risk was expressed as a continuously distributed score calculated as the average of the standardized values of the six subcomponents. There was a positive association between TV viewing and adiposity (p = 0.021). However, after adjustment for PA, gender, age group, study location, sexual maturity, smoking status, birth weight, and parental socio-economic status, the association of TV viewing with clustered metabolic risk was no longer significant (p = 0.053). PA was independently and inversely associated with systolic and diastolic blood pressure, fasting glucose, insulin (all p < 0.01), and triglycerides (p = 0.02). PA was also significantly and inversely associated with the clustered risk score (p < 0.0001), independently of obesity and other confounding factors.
  
  
  CONCLUSIONS
  TV viewing and PA may be separate entities and differently associated with adiposity and metabolic risk. The association between TV viewing and clustered metabolic risk is mediated by adiposity, whereas PA is associated with individual and clustered metabolic-risk indicators independently of obesity. Thus, preventive action against metabolic risk in children may need to target TV viewing and PA separately.
authors.affiliation: Epidemiology Unit, Medical Research Council, Cambridge, United Kingdom. Ulf.Ekelund@mrc-epid.cam.ac.uk
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekelund
authors.forename: Søren
authors.initials: S
authors.lastname: Brage
authors.forename: Karsten
authors.initials: K
authors.lastname: Froberg
authors.forename: Maarike
authors.initials: M
authors.lastname: Harro
authors.forename: Sigmund A
authors.initials: SA
authors.lastname: Anderssen
authors.forename: Luis B
authors.initials: LB
authors.lastname: Sardinha
authors.forename: Chris
authors.initials: C
authors.lastname: Riddoch
authors.forename: Lars Bo
authors.initials: LB
authors.lastname: Andersen
mesh_terms: D000293:Adolescent; D002648:Child; D015986:Confounding Factors, Epidemiologic; D003430:Cross-Sectional Studies; D003718:Denmark; D004957:Estonia; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D009765:Obesity / Q000453:epidemiology*; D011174:Portugal; D012308:Risk Management; D013690:Television; D013997:Time Factors