title: African genetic admixture is associated with body composition and fat distribution in a cross-sectional study of children.
abstract: OBJECTIVE
  Although differences in body composition parameters among African American (AA), Hispanic American (HA) and European American (EA) children are well documented, the factors underlying these differences are not completely understood. Environmental and genetic contributors have been evaluated as contributors to observed differences. This study evaluated the extent to which African or European ancestral genetic background influenced body composition and fat distribution in 301 peripubertal AA (n = 107), HA (n = 79) and EA (n = 115) children aged 7-12.
  
  
  METHODS
  Estimates of African admixture (AFADM) and European admixture (EUADM) were obtained for every subject using 142 ancestry informative DNA markers. Dual energy X-ray absorptiometry and computed tomography scanning were used to determine body composition and abdominal fat distribution, respectively. Multiple regression models were conducted to evaluate the contribution of admixture estimates to body composition and fat distribution.
  
  
  RESULTS
  Greater AFADM was associated with lower fat mass (P = 0.0163), lower total abdominal adipose tissue (P = 0.0006), lower intra-abdominal adipose tissue (P = 0.0035), lower subcutaneous abdominal adipose tissue (P = 0.0115) and higher bone mineral content (BMC) (P = 0.0253), after adjusting for socio-economic status, sex, age, height, race/ethnicity and pubertal status. Greater EUADM was associated with lower lean mass (LM) (P = 0.0056).
  
  
  CONCLUSIONS
  These results demonstrate that ancestral genetic background contributes to racial/ethnic differences in body composition above and beyond the effects of racial/ethnic classification and suggest a genetic contribution to total body fat accumulation, abdominal adiposity, LM and BMC.
authors.affiliation: Department of Nutrition Sciences and the Nutrition and Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Cardel
authors.forename: P B
authors.initials: PB
authors.lastname: Higgins
authors.forename: A L
authors.initials: AL
authors.lastname: Willig
authors.forename: A D
authors.initials: AD
authors.lastname: Keita
authors.forename: K
authors.initials: K
authors.lastname: Casazza
authors.forename: B A
authors.initials: BA
authors.lastname: Gower
authors.forename: J R
authors.initials: JR
authors.lastname: Fernández
mesh_terms: D015502:Absorptiometry, Photon; D001741:Black or African American / Q000235:genetics* / Q000706:statistics & numerical data; D000407:Alabama / Q000453:epidemiology; D001823:Body Composition / Q000235:genetics*; D050218:Body Fat Distribution; D015519:Bone Density / Q000235:genetics; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006630:Hispanic or Latino / Q000235:genetics* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D050507:Subcutaneous Fat, Abdominal; D014057:Tomography, X-Ray Computed; D044465:White People / Q000235:genetics* / Q000706:statistics & numerical data