title: The relation between internet use and overweight among adolescents: a longitudinal study in Switzerland.
abstract: OBJECTIVE
  This longitudinal study aimed to investigate the characteristics and predictive risk factors of overweight among adolescents. The hypothesis was that baseline overweight predicted most overweight over time compared to other factors, especially excessive internet use.
  
  
  METHODS
  A sample of 621 youths were followed from age 14 (T0 Spring 2012) to age 16 (T1 Spring 2014) in Switzerland. Participants were divided into two groups according to their weight at the final assessment: overweight and non-overweight. At T0, participants reported demographic, health, substance use and internet use data. A logistic regression was performed to assess the explanatory variables of overweight at T1. Data are presented as adjusted odds ratios (aORs) with 95% confidence interval.
  
  
  RESULTS
  The 2-year evolution showed a net BMI increase of 4.8%. Overweight adolescents were significantly more likely to be male, to live in an urban area, to be on a diet and to report using the internet more than 2 h per day on weekends at T0. However, with the addition of baseline overweight, only the excessive use of internet on weekends remained as an explanatory variable. An adolescent who was already overweight at T0 had a more than 20-fold risk (aOR 21.04) of being overweight 2 years later. Moreover, among adolescents becoming overweight between T0 and T1, internet use did not show any significant effect.
  
  
  CONCLUSIONS
  The risk of being overweight is mostly influenced by weight status at baseline compared to excessive internet use. Thus, our results do not confirm the negative effect of internet on healthier activities. Internet use could at most reinforce an already existing risk of being overweight.
authors.affiliation: Research Group on Adolescent Health (GRSA), Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Y
authors.initials: Y
authors.lastname: Barrense-Dias
authors.affiliation: Institute of Social Sciences & LIVES, University of Lausanne, Lausanne, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Berchtold
authors.affiliation: Research Group on Adolescent Health (GRSA), Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Akre
authors.affiliation: Research Group on Adolescent Health (GRSA), Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: J-C
authors.initials: JC
authors.lastname: Surís
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D015992:Body Mass Index; D003201:Computers; D004032:Diet; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D015438:Health Behavior; D006801:Humans; D020407:Internet; D007899:Leisure Activities; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity; D016017:Odds Ratio; D063766:Pediatric Obesity / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology