title: Genotype by energy expenditure interaction and body composition traits: The Portuguese Healthy Family Study.
abstract: OBJECTIVE
  Energy expenditure has been negatively correlated with fat accumulation. However, this association is highly variable. In the present study we applied a genotype by environment interaction method to examine the presence of Genotype x by Total Daily Energy Expenditure and Genotype x by Daily Energy Expenditure interactions in the expression of different body composition traits.
  
  
  RESULTS
  A total of 958 subjects from 294 families of The Portuguese Healthy Family Study were included in the analysis. TDEE and DEE were assessed using a physical activity recall. Body fat percentages were measured with a bioelectrical impedance scale. GxTDEE and GxDEE examinations were performed using SOLAR 4.0 software. All BC traits were significantly heritable, with heritabilities ranging from 21% to 34%. The GxTDEE and GxDEE interaction models fitted the data better than the polygenic model for all traits. For all traits, a significant GxTDEE and GxDEE interaction was due to variance heterogeneity among distinct levels of TDEE and DEE. For WC, GxTDEE was also significant due to the genetic correlation function.
  
  
  CONCLUSIONS
  TDEE and DEE are environmental constraints associated with the expression of individuals' BC genotypes, leading to variability in the phenotypic expression of BC traits.
authors.affiliation: CIFI2D, Faculty of Sports, University of Porto, Rua Dr. Plácido Costa 91, 4200-450 Porto, Portugal.
authors.forename: D M
authors.initials: DM
authors.lastname: Santos
authors.affiliation: Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
authors.forename: P T
authors.initials: PT
authors.lastname: Katzmarzyk
authors.affiliation: Texas Biomedical Research Institute, San Antonio, Texas 78227-5301, USA.
authors.forename: V P
authors.initials: VP
authors.lastname: Diego
authors.affiliation: CIFI2D, Faculty of Sports, University of Porto, Rua Dr. Plácido Costa 91, 4200-450 Porto, Portugal.
authors.forename: T N
authors.initials: TN
authors.lastname: Gomes
authors.affiliation: CIFI2D, Faculty of Sports, University of Porto, Rua Dr. Plácido Costa 91, 4200-450 Porto, Portugal.
authors.forename: F K
authors.initials: FK
authors.lastname: Santos
authors.affiliation: Texas Biomedical Research Institute, San Antonio, Texas 78227-5301, USA.
authors.forename: J
authors.initials: J
authors.lastname: Blangero
authors.affiliation: CIFI2D, Faculty of Sports, University of Porto, Rua Dr. Plácido Costa 91, 4200-450 Porto, Portugal.
authors.forename: J A
authors.initials: JA
authors.lastname: Maia
mesh_terms: D000293:Adolescent; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D002648:Child; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005838:Genotype; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015233:Models, Statistical; D011174:Portugal / Q000453:epidemiology; D055105:Waist Circumference / Q000502:physiology