title: Obesity-susceptibility loci and their influence on adiposity-related traits in transition from adolescence to adulthood--the HUNT study.
abstract: BACKGROUND
  Obesity-susceptibility loci have been related to adiposity traits in adults and may affect body fat estimates in adolescence. There are indications that different sets of obesity-susceptibility loci influence level of and change in obesity-related traits from adolescence to adulthood.
  
  
  OBJECTIVE
  To investigate whether previously reported obesity-susceptible loci in adults influence adiposity traits in adolescence and change in BMI and waist circumference (WC) from adolescence into young adulthood. We also examined whether physical activity modifies the effects of these genetic loci on adiposity-related traits.
  
  
  METHODS
  Nine obesity-susceptibility variants were genotyped in 1 643 adolescents (13-19 years old) from the HUNT study, Norway, who were followed-up into young adulthood. Lifestyle was assessed using questionnaires and anthropometric measurements were taken. The effects of genetic variants individually and combined in a genetic predisposition score (GPS) on obesity-related traits were studied cross-sectionally and longitudinally. A modifying effect of physical activity was tested.
  
  
  RESULTS
  The GPS was significantly associated to BMI (B: 0.046 SD/allele [0.020, 0.073], p = 0.001) in adolescence and in young adulthood (B: 0.041 SD/allele [0.015, 0.067], p = 0.002) as it was to waist circumference (WC). The GPS was not associated to change in BMI (p = 0.762) or WC (p = 0.726). We found no significant interaction effect between the GPS and physical activity.
  
  
  CONCLUSIONS
  Our observations suggest that obesity-susceptibility loci established in adults affect BMI and WC already in adolescence. However, an association with change in adiposity-related traits from adolescence to adulthood could not be verified for these loci. Neither could an attenuating effect of physical activity on the association between the obesity-susceptibility genes and body fat estimates be revealed.
authors.affiliation: HUNT Research Center, Levanger, Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. Koenraad.cuypers@ntnu.no
authors.forename: Koenraad Frans
authors.initials: KF
authors.lastname: Cuypers
authors.forename: Ruth J F
authors.initials: RJ
authors.lastname: Loos
authors.forename: Kirsti
authors.initials: K
authors.lastname: Kvaløy
authors.forename: Bettina
authors.initials: B
authors.lastname: Kulle
authors.forename: Pål
authors.initials: P
authors.lastname: Romundstad
authors.forename: Turid Lingaas
authors.initials: TL
authors.lastname: Holmen
mesh_terms: D000273:Adipose Tissue / Q000254:growth & development; D050154:Adiposity / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000483:Alleles; D015992:Body Mass Index; D005260:Female; D056426:Genetic Loci; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D009043:Motor Activity; D009664:Norway; D009765:Obesity / Q000235:genetics*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D011795:Surveys and Questionnaires; D055105:Waist Circumference / Q000235:genetics*; D044465:White People