title: Body composition of newborn twins: intrapair differences.
abstract: OBJECTIVE
  To measure body composition in newborn twins and to test the hypothesis that differences in body weights between twins are reflected proportionally by their differences in various components of body composition.
  
  
  METHODS
  48 pairs of newborn twins delivered at a tertiary teaching hospital had dual energy x-ray absorptiometry (DXA) body composition measurement for bone mineral content (BMC), lean and fat mass (LM, FM). Data analyzed with regression and analysis of variance.
  
  
  RESULTS
  Body weight, BMC, LM and FM increased with increased gestational age (p < 0.001). The percent difference in BW between each twin pair was significantly correlated with percent difference in BMC, LM, and FM (p < 0.001). However, mean (+/- SD) percent difference in body weight (14.3+/-10.0%) was significantly lower (p < 0.001) than FM (26.0+/-15.0%) but was not significantly different from LM (13.4+/-9.0%) or BMC (15.9+/-11.6%).
  
  
  CONCLUSIONS
  In newborn twins, body weight and body composition varies with gestational age. For any twin pair, a difference in body weight was correlated with but not proportional to differences in individual components of body composition.
authors.affiliation: Department of Pediatrics, Obstetrics and Gynecology, University of Tennessee, Memphis, USA.
authors.forename: Belinda
authors.initials: B
authors.lastname: Koo
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Walters
authors.forename: Elaine
authors.initials: E
authors.lastname: Hockman
authors.forename: Winston
authors.initials: W
authors.lastname: Koo
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000000981:diagnostic imaging*; D000367:Age Factors; D000704:Analysis of Variance; D000886:Anthropometry; D001823:Body Composition / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D013851:Thinness / Q000000981:diagnostic imaging*; D014427:Twins