title: Relationships between neonatal weight, limb lengths, skinfold thicknesses, body breadths and circumferences in an Australian cohort.
abstract: BACKGROUND
  Low birth weight has been consistently associated with adult chronic disease risk. The thrifty phenotype hypothesis assumes that reduced fetal growth impacts some organs more than others. However, it remains unclear how birth weight relates to different body components, such as circumferences, adiposity, body segment lengths and limb proportions. We hypothesized that these components vary in their relationship to birth weight.
  
  
  METHODS
  We analysed the relationship between birth weight and detailed anthropometry in 1270 singleton live-born neonates (668 male) from the Mater-University of Queensland Study of Pregnancy (Brisbane, Australia). We tested adjusted anthropometry for correlations with birth weight. We then performed stepwise multiple regression on birth weight of: body lengths, breadths and circumferences; relative limb to neck-rump proportions; or skinfold thicknesses. All analyses were adjusted for sex and gestational age, and used logged data.
  
  
  RESULTS
  Circumferences, especially chest, were most strongly related to birth weight, while segment lengths (neck-rump, thigh, upper arm, and especially lower arm and lower leg) were relatively weakly related to birth weight, and limb lengths relative to neck-rump length showed no relationship. Skinfolds accounted for 36% of birth weight variance, but adjusting for size (neck-rump, thigh and upper arm lengths, and head circumference), this decreased to 10%. There was no evidence that heavier babies had proportionally thicker skinfolds.
  
  
  CONCLUSIONS
  Neonatal body measurements vary in their association with birth weight: head and chest circumferences showed the strongest associations while limb segment lengths did not relate strongly to birth weight. After adjusting for body size, subcutaneous fatness accounted for a smaller proportion of birth weight variance than previously reported. While heavier babies had absolutely thicker skinfolds, this was proportional to their size. Relative limb to trunk length was unrelated to birth weight, suggesting that limb proportions at birth do not index factors relevant to prenatal life.
authors.affiliation: Newnham College, University of Cambridge, Cambridge, United Kingdom; Division of Biological Anthropology, Department of Archaeology and Anthropology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Emma
authors.initials: E
authors.lastname: Pomeroy
authors.affiliation: Division of Biological Anthropology, Department of Archaeology and Anthropology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Jay T
authors.initials: JT
authors.lastname: Stock
authors.affiliation: Population Policy and Practice, UCL Institute of Child Health, London, United Kingdom.
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Cole
authors.affiliation: School of Medicine, Mater Clinical School, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: O'Callaghan
authors.affiliation: Division of Biological Anthropology, Department of Archaeology and Anthropology, University of Cambridge, Cambridge, United Kingdom; Childhood Nutrition Research Centre, UCL Institute of Child Health, London, United Kingdom.
authors.forename: Jonathan C K
authors.initials: JC
authors.lastname: Wells
mesh_terms: D000328:Adult; D000886:Anthropometry; D001315:Australia; D001724:Birth Weight; D001827:Body Height; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D012044:Regression Analysis; D012885:Skinfold Thickness; D055105:Waist Circumference