title: First-borns have a higher metabolic rate and carry a higher metabolic risk in young women attending a weight loss clinic.
abstract: BACKGROUND
  Birth order has been associated with variability in early life growth and subsequent obesity risk, but the consequent metabolic risks have not been assessed.
  
  
  OBJECTIVE
  To quantify the metabolic risk in young adulthood of being first-born relative to those born second or subsequently.
  
  
  METHODS
  Body composition, resting metabolic rate and metabolic risk were assessed in 383 women, aged 18-35 years, from a clinical setting in southern Italy.
  
  
  RESULTS
  First-borns had increased body mass index, adiposity and metabolic risk (p<0.05) and increased resting metabolic rate adjusted for fat-free mass (p<0.05) in the Italian women.
  
  
  CONCLUSIONS
  First-born status is associated with significantly elevated metabolic risk in a clinical population of overweight and obese young women attending a weight loss clinic. If these findings are confirmed in other studies, they may suggest that the prevalence of the metabolic syndrome worldwide may increase as a function of the trend to smaller family size.
authors.affiliation: Nutrition Physiology, Department of Neuroscience, Faculty of Medicine, University "Federico II", via Pansini 5, 80100, Napoli, Italy. masiervo@yahoo.com
authors.forename: M
authors.initials: M
authors.lastname: Siervo
authors.forename: B C M
authors.initials: BC
authors.lastname: Stephan
authors.forename: A
authors.initials: A
authors.lastname: Colantuoni
authors.forename: J C K
authors.initials: JC
authors.lastname: Wells
mesh_terms: D050154:Adiposity / Q000502:physiology; D000293:Adolescent; D000328:Adult; D001481:Basal Metabolism / Q000502:physiology*; D001722:Birth Order; D001823:Body Composition / Q000502:physiology*; D005260:Female; D006801:Humans; D009765:Obesity / Q000378:metabolism*; D015431:Weight Loss / Q000502:physiology*