title: Familial resemblance of body composition in prepubertal girls and their biological parents.
abstract: BACKGROUND
  Heritability estimates for body mass index (BMI; in kg/m(2)) in children generally have been derived from twin and adoption studies. However, BMI does not reflect total or regional body composition.
  
  
  OBJECTIVE
  We evaluated the familial resemblance of body composition between prepubertal girls of normal weight and body fatness and their parents by using state-of-the-art technology.
  
  
  METHODS
  The subjects were 101 girls [mean age: 8.5 +/- 0.4 y; percentage body fat (%BF): 12-30%] and their biological parents. Weight, height, and body composition [fat mass (FM), fat-free mass (FFM), and %BF] were measured with dual-energy X-ray absorptiometry (DXA) and total body potassium (TBK).
  
  
  RESULTS
  Weight, height, and BMI showed low-to-moderate similarity between the girls and both their parents (r = 0.29-0.44, P < 0.01). The girls' FM, FFM, and %BF were significantly related to both parents' body composition. Cross-generational equations were developed for DXA, eg, child's %BF = 12.4 + (0.158 paternal %BF) + (0.145 maternal %BF) (adjusted r(2) = 0.16, P < 0.001). Regional analysis with DXA showed that the adjusted r(2) values for the arm, trunk, and leg regions, respectively, were 0.17, 0.33, and 0.31 for lean tissue mass and 0.11, 0.14, and 0.09 for FM. TBK showed a similar relation between parents and girls (r = 0.28-0.47, P < 0.01). Significant heritability (h(2) +/- SE) was detected for BMI (0.35 +/- 0.17, P = 0.03) and %BF measured with DXA (0.50 +/- 0.12, P = 0.0001).
  
  
  CONCLUSIONS
  The body composition of prepubertal girls of normal weight and body fatness is significantly related to the body composition of both biological parents.
authors.affiliation: Center for Human Nutrition, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205, USA. mtreuth@jhsph.edu
authors.forename: M S
authors.initials: MS
authors.lastname: Treuth
authors.forename: N F
authors.initials: NF
authors.lastname: Butte
authors.forename: K J
authors.initials: KJ
authors.lastname: Ellis
authors.forename: L J
authors.initials: LJ
authors.lastname: Martin
authors.forename: A G
authors.initials: AG
authors.lastname: Comuzzie
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000328:Adult; D001823:Body Composition / Q000235:genetics*; D015992:Body Mass Index; D002648:Child; D005220:Fathers; D005260:Female; D006801:Humans; D008297:Male; D009035:Mothers; D011188:Potassium / Q000378:metabolism
chemical_list: D011188:Potassium