title: Associations between indicators of screen time and adiposity indices in Portuguese children.
abstract: OBJECTIVE
  To examine associations between three types of screen time (TV, electronic games (EG), and personal computer (PC)) and two proxies of adiposity (body mass index (BMI) and sum of skinfolds) in children.
  
  
  METHODS
  The sample comprised 17,509 children aged 2-13 years who participated in the 2009/10 Portuguese Prevalence Study of Obesity in Childhood.
  
  
  METHODS
  Complex samples generalised linear models, using school as a cluster variable were ran separately for each combination of ST predictor and adiposity-related outcome, adjusting for covariates including age, sex, physical activity, diet, and parental factors. Missing values in predictors and covariates were imputed.
  
  
  RESULTS
  Watching TV for >2h/day compared to <1h/day was associated with higher age- and sex-specific BMI standard deviation score (coefficient: 0.06, 95% CI: 0.01 to 0.12, linear trend p=0.008) and sum of skinfolds (logged and back transformed 0.04, 0.02 to 0.07, p=<0.001). We also found weak evidence for an inverse association between PC and BMI.
  
  
  CONCLUSIONS
  Associations between ST and adiposity differ by both type of ST and type of adiposity marker. Only TV viewing was consistently associated with adiposity. Studies using a single adiposity marker looking at total screen time or total sedentary behaviour time may miss or confound type-specific associations.
authors: Department of Epidemiology and Public Health, University College London, London, UK. e.stamatakis@ucl.ac.uk
authors: Emmanuel
authors: E
authors: Stamatakis
authors: Ngaire
authors: N
authors: Coombs
authors: Russell
authors: R
authors: Jago
authors: Augusta
authors: A
authors: Gama
authors: Isabel
authors: I
authors: Mourão
authors: Helena
authors: H
authors: Nogueira
authors: Vítor
authors: V
authors: Rosado
authors: Cristina
authors: C
authors: Padez
mesh_terms: D050154:Adiposity; D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008838:Microcomputers / Q000706:statistics & numerical data; D010287:Parent-Child Relations; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D057185:Sedentary Behavior; D012885:Skinfold Thickness; D013690:Television / Q000706:statistics & numerical data*; D013997:Time Factors; D018910:Video Games / Q000706:statistics & numerical data*