title: Screen time behaviours may interact with obesity genes, independent of physical activity, to influence adolescent BMI in an ethnically diverse cohort.
abstract: BACKGROUND
  There has been little investigation of gene-by-environment interactions related to sedentary behaviour, a risk factor for obesity defined as leisure screen time (ST; i.e. television, video and computer games).
  
  
  OBJECTIVE
  To test the hypothesis that limiting ST use attenuates the genetic predisposition to increased body mass index (BMI), independent of physical activity.
  
  
  METHODS
  Using 7642 wave II participants of the National Longitudinal Study of Adolescent Health, (Add Health; mean = 16.4 years, 52.6% female), we assessed the interaction of ST (h week(-1) ) and 41 established obesity single nucleotide polymorphisms (SNPs) with age- and sex-specific BMI Z-scores in 4788 European-American (EA), 1612 African-American (AA) and 1242 Hispanic American (HA) adolescents.
  
  
  RESULTS
  Nominally significant SNP*ST interaction were found for FLJ35779 in EA, GNPDA2 in AA and none in HA (EA: beta [SE] = 0.016[0.007]), AA: beta [SE] = 0.016[0.011]) per 7 h week(-1) ST and one risk allele in relation to BMI Z-score.
  
  
  CONCLUSIONS
  While for two established BMI loci, we find evidence that high levels of ST exacerbate the influence of obesity susceptibility variants on body mass; overall, we do not find strong evidence for interactions between the majority of established obesity loci. However, future studies with larger sample sizes, or that may build on our current study and the growing published literature, are clearly warranted.
authors.affiliation: Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, USA; Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: M
authors.initials: M
authors.lastname: Graff
authors.forename: K E
authors.initials: KE
authors.lastname: North
authors.forename: A S
authors.initials: AS
authors.lastname: Richardson
authors.forename: K M
authors.initials: KM
authors.lastname: Young
authors.forename: K L
authors.initials: KL
authors.lastname: Mohlke
authors.forename: L A
authors.initials: LA
authors.lastname: Lange
authors.forename: E M
authors.initials: EM
authors.lastname: Lange
authors.forename: K M
authors.initials: KM
authors.lastname: Harris
authors.forename: P
authors.initials: P
authors.lastname: Gordon-Larsen
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D009043:Motor Activity; D009765:Obesity / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D057185:Sedentary Behavior / Q000208:ethnology; D013690:Television / Q000706:statistics & numerical data; D018910:Video Games / Q000706:statistics & numerical data; D015430:Weight Gain / Q000208:ethnology / Q000235:genetics*
keywords: Adolescent BMI; Gene-environment interactions; Obesity genes; screen time
references.citation: Nutr Diabetes. 2012 Sep 24;2:e47
references.pmid: 23168566
references.citation: Circulation. 2012 Oct 9;126(15):1821-7
references.pmid: 22949498
references.citation: Int J Obes (Lond). 2009 Jan;33(1):29-36
references.pmid: 19048013
references.citation: Hum Mol Genet. 2010 Jul 1;19(13):2725-38
references.pmid: 20400458
references.citation: Am J Clin Nutr. 2004 Sep;80(3):569-75
references.pmid: 15321794
references.citation: Bioinformatics. 2010 Sep 1;26(17):2190-1
references.pmid: 20616382
references.citation: JAMA. 2004 May 12;291(18):2229-36
references.pmid: 15138245
references.citation: Demography. 2010 Feb;47(1):1-22
references.pmid: 20355681
references.citation: Pediatr Obes. 2014 Apr;9(2):e35-46
references.pmid: 23529959
references.citation: Am J Public Health. 1998 Feb;88(2):277-80
references.pmid: 9491022
references.citation: JAMA. 2003 Apr 9;289(14):1785-91
references.pmid: 12684356
references.citation: Pediatrics. 2002 Jan;109(1):45-60
references.pmid: 11773541
references.citation: Nat Genet. 2009 Jan;41(1):18-24
references.pmid: 19079260
references.citation: Pediatrics. 2000 Jul;106(1 Pt 1):52-8
references.pmid: 10878149
references.citation: Nat Genet. 2010 Nov;42(11):937-48
references.pmid: 20935630
references.citation: Twin Res Hum Genet. 2006 Dec;9(6):988-97
references.pmid: 17254442
references.citation: Nat Genet. 2009 Jan;41(1):25-34
references.pmid: 19079261
references.citation: Nat Genet. 2009 Feb;41(2):157-9
references.pmid: 19151714
references.citation: Nat Genet. 2010 Dec;42(12):1077-85
references.pmid: 21102462
references.citation: Am J Clin Nutr. 2009 Aug;90(2):425-8
references.pmid: 19553294
references.citation: PLoS Med. 2011 Nov;8(11):e1001116
references.pmid: 22069379
references.citation: Int J Obes (Lond). 2005 Sep;29 Suppl 2:S84-96
references.pmid: 16385758
references.citation: Med Sci Sports Exerc. 1996 Jul;28(7):840-51
references.pmid: 8832538
references.citation: JAMA. 1997 Sep 10;278(10):823-32
references.pmid: 9293990