title: Are associations between electronic media use and BMI different across levels of physical activity?
abstract: BACKGROUND
  The use of electronic media has been found to be a risk factor for higher BMI and for being overweight. Physical activity has been found to be associated with lower BMI and lower risk for being overweight. Little is known about whether the associations between physical activity and electronic media use are additive or interactive in predicting BMI and risk for overweight among adolescents.
  
  
  METHODS
  The data used in this study stem from the 2009/2010 survey of "Health Behaviour in School-aged Children (HBSC) study: A WHO Cross-National Survey. The sample consisted of 107184 13 and 15 year students from 30 different countries. Multilevel regression models were used to produce the presented estimates.
  
  
  RESULTS
  Overall, 18% of boys and 11% of girls were classified as overweight. EM use was found to be associated with increased BMI z-scores and odds for overweight among both boys and girls who did not comply with physical activity guidelines. Among physically active adolescents, EM was found to be significantly associated with BMI or odds for overweight among girls, but not among boys.
  
  
  CONCLUSIONS
  While the usage of EM appear to be inconsequential for BMI and the risk of overweight among physically active boys, we find evidence indicating that EM use is associated with BMI and risk for overweight among girls, including those who report complying with MVPA guidelines.
authors.affiliation: Division for Mental Health, Norwegian institute of Public Health, Bergen, Norway. ole.melkevik@fhi.no.
authors.forename: Ole
authors.initials: O
authors.lastname: Melkevik
authors.affiliation: NLA University College, Bergen, Norway. EllenMerete.Haug@NLA.no.
authors.forename: Ellen
authors.initials: E
authors.lastname: Haug
authors.affiliation: National Institute of Public Health, University of Southern Denmark, Odense, Denmark. mera@niph.dk.
authors.forename: Mette
authors.initials: M
authors.lastname: Rasmussen
authors.affiliation: Department of Health Promotion and Development, University of Bergen, Bergen, Norway. anne-siri.fismen@iuh.uib.no.
authors.forename: Anne Siri
authors.initials: AS
authors.lastname: Fismen
authors.affiliation: Department of Health Promotion and Development, University of Bergen, Bergen, Norway. bente.wold@iuh.uib.no.
authors.forename: Bente
authors.initials: B
authors.lastname: Wold
authors.affiliation: Department of Public Health and Microbiology, University of Turin, Turin, Italy. alberto.borraccino@hbsc.org.
authors.forename: Alberto
authors.initials: A
authors.lastname: Borraccino
authors.affiliation: Center for Kinanthropology Research, Palacky University, Olomouc, Czech Republic. erik.sigmund@gmail.com.
authors.forename: Erik
authors.initials: E
authors.lastname: Sigmund
authors.affiliation: Faculty of Psychology and Educational Sciences, Babes Bolyai University, Cluj-Napoca, Romania. robertbalazsi@psychology.ro.
authors.forename: Robert
authors.initials: R
authors.lastname: Balazsi
authors.affiliation: Bielefeld University, School of Public Health, Department of Prevention and Health Promotion, Bielefeld, Germany. jens.bucksch@uni-bielefeld.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Bucksch
authors.affiliation: Child and Adolescent Health Research Unit, University of St Andrews, Scotland, UK. jci2@st-andrews.ac.uk.
authors.forename: Jo
authors.initials: J
authors.lastname: Inchley
authors.affiliation: Faculdade de Motricidade Humana, Universidade de Lisboa, Lisboa, Portugal. margaridagaspar@netcabo.pt.
authors.forename: Margarida Gaspar
authors.initials: MG
authors.lastname: de Matos
authors.affiliation: Department of Health Promotion and Development, University of Bergen, Bergen, Norway. oddrun.samdal@rektor.uib.no.
authors.forename: Oddrun
authors.initials: O
authors.lastname: Samdal
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D003146:Communications Media; D003201:Computers / Q000706:statistics & numerical data*; D015444:Exercise; D005260:Female; D006801:Humans; D038622:Internationality; D008297:Male; D050177:Overweight / Q000453:epidemiology*; D012307:Risk Factors; D017678:Sex Distribution; D013334:Students; D013690:Television / Q000706:statistics & numerical data*; D018910:Video Games / Q000706:statistics & numerical data*