title: Association of DXA-derived bone mineral density and fat mass with African ancestry.
abstract: BACKGROUND
  Both genes and environment have been implicated in determining the complex body composition phenotypes in individuals of European ancestry; however, few studies have been conducted in other race/ethnic groups.
  
  
  OBJECTIVE
  We conducted a genome-wide admixture mapping study in an attempt to localize novel genomic regions associated with genetic ancestry.
  
  
  METHODS
  We selected a sample of 842 African-American women from the Women's Health Initiative single nucleotide polymorphism (SNP) Health Association Resource for whom several dual-energy X-ray absorptiometry (DXA)-derived bone mineral density (BMD) and fat mass phenotypes were available.
  
  
  METHODS
  We derived both global and local ancestry estimates for each individual from Affymetrix 6.0 data and analyzed the correlation of DXA phenotypes with global African ancestry. For each phenotype, we examined the association of local genetic ancestry (number of African ancestral alleles at each marker) and each DXA phenotype at 570 282 markers across the genome in additive models with adjustment for important covariates.
  
  
  RESULTS
  We identified statistically significant correlations of whole-body fat mass, trunk fat mass, and all 6 measures of BMD with a proportion of African ancestry. Genome-wide (admixture) significance for femoral neck BMD was achieved across 2 regions ∼3.7 MB and 0.3 MB on chromosome 19q13; similarly, total hip and intertrochanter BMD were associated with local ancestry in these regions. Trunk fat was the most significant fat mass phenotype showing strong, but not genomewide significant associations on chromosome Xp22.
  
  
  CONCLUSIONS
  Our results suggest that genomic regions in postmenopausal African-American women contribute to variance in BMD and fat mass existence and warrant further study.
authors: Department of Social and Preventive Medicine, University at Buffalo, Buffalo, NY14214-8001, USA. hmochs2@buffalo.edu
authors: Heather M
authors: HM
authors: Ochs-Balcom
authors: Leah
authors: L
authors: Preus
authors: Jean
authors: J
authors: Wactawski-Wende
authors: Jing
authors: J
authors: Nie
authors: Nicholas A
authors: NA
authors: Johnson
authors: Fouad
authors: F
authors: Zakharia
authors: Hua
authors: H
authors: Tang
authors: Chris
authors: C
authors: Carlson
authors: Cara
authors: C
authors: Carty
authors: Zhao
authors: Z
authors: Chen
authors: Thomas
authors: T
authors: Hoffman
authors: Carolyn M
authors: CM
authors: Hutter
authors: Rebecca D
authors: RD
authors: Jackson
authors: Robert C
authors: RC
authors: Kaplan
authors: Li
authors: L
authors: Li
authors: Song
authors: S
authors: Liu
authors: Marian L
authors: ML
authors: Neuhouser
authors: Ulrike
authors: U
authors: Peters
authors: John
authors: J
authors: Robbins
authors: Michael F
authors: MF
authors: Seldin
authors: Timothy A
authors: TA
authors: Thornton
authors: Cheryl L
authors: CL
authors: Thompson
authors: Charles
authors: C
authors: Kooperberg
authors: Lara E
authors: LE
authors: Sucheston
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology*; D050154:Adiposity / Q000208:ethnology* / Q000235:genetics / Q000502:physiology; D001741:Black or African American / Q000235:genetics / Q000706:statistics & numerical data; D000368:Aged; D044383:Black People / Q000235:genetics / Q000706:statistics & numerical data; D001823:Body Composition / Q000502:physiology; D015519:Bone Density / Q000235:genetics; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D005260:Female; D005272:Femur Neck; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D009929:Organ Size / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000502:physiology