Associations between indicators of screen time and adiposity indices in Portuguese children

Prev Med. 2013 May;56(5):299-303. doi: 10.1016/j.ypmed.2013.02.006. Epub 2013 Feb 20.


Objectives: 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.

Design: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adiposity*
  • Adolescent
  • Body Mass Index
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Male
  • Microcomputers / statistics & numerical data
  • Parent-Child Relations
  • Portugal / epidemiology
  • Prevalence
  • Sedentary Behavior
  • Skinfold Thickness
  • Television / statistics & numerical data*
  • Time Factors
  • Video Games / statistics & numerical data*