title: Clustering of metabolic risk factors in young adults: genes and environment.
abstract: OBJECTIVE
  Evidence of a genetic basis of metabolic risk factors (MRFs) is growing. Studies examining the genetic and environmental basis of the clustering of MRFs, grouped together in the metabolic syndrome (MetS), are however sparse. The aim of this study therefore was to study the heritabilities of the MRFs and the genetic and environmental correlations between the MRFs.
  
  
  METHODS
  Study participants were 768 Caucasian twins coming from 418 pairs (18-34 years). MRFs were those included in the National Cholesterol Education Program Adult Treatment Panel III definition of the MetS. Multivariate path analysis on the continuous MRFs of the MetS was implemented.
  
  
  RESULTS
  Heritabilities ranged between 47.0% and 80.2% (men) and 58.5% and 77.9% (women) for the individual MRFs. Evidence was found for overarching genetic (A) and environmental (E) sources of variance, both however loading mainly on waist circumference. Furthermore, the model included a 'lipids' and a 'blood pressure'-factor both in part attributable to A and E. The majority of the variance however was MRF-specific.
  
  
  CONCLUSIONS
  Based on our sample of young adults with a low prevalence of the MetS, it can be concluded that both genes and environment contribute significantly to the clustering of the MRFs although the majority of the variation is MRF-specific. Therefore, future QTL searches in young adults may want to focus on MRF-specific loci, rather than 'cluster-phenotypes' such as the MetS.
authors.affiliation: Faculty of Kinesiology and Rehabilitation Sciences, Department of Biomedical Kinesiology, Research Center for Exercise and Health, Katholieke Universiteit Leuven, Leuven, Belgium. Maarten.Peeters@FABER.kuleuven.be
authors.forename: Maarten W
authors.initials: MW
authors.lastname: Peeters
authors.forename: Martine A
authors.initials: MA
authors.lastname: Thomis
authors.forename: Ruth J F
authors.initials: RJ
authors.lastname: Loos
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Derom
authors.forename: Robert
authors.initials: R
authors.lastname: Fagard
authors.forename: Robert F
authors.initials: RF
authors.lastname: Vlietinck
authors.forename: Gaston P
authors.initials: GP
authors.lastname: Beunen
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000235:genetics*; D015999:Multivariate Analysis; D012307:Risk Factors; D012737:Sex Factors; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics; D044465:White People / Q000235:genetics