title: Serum IGF-I levels are similar in Samoan, Māori and European populations despite differences in body composition.
abstract: OBJECTIVE
  To determine if serum IGF-I concentrations are similar in healthy adult subjects from the Samoan, Māori and European populations in New Zealand.
  
  
  METHODS
  Serum IGF-I concentration was measured in 75 healthy adults, aged 18-50 years, of Samoan (n=23), Māori (n=22) and European (n=30) descent. Body composition was assessed using standard anthropomorphic measures. In addition all subjects had body composition assessed by Dual energy X-ray absorptiometry (DXA).
  
  
  RESULTS
  Weight, body mass index (BMI), and fat mass were significantly greater in Māori and Samoan subjects than European subjects (ANOVA p=0.006, p=0.0003, p=0.03, respectively). However, serum IGF-I concentration was similar between the groups (European 186.8 SEM 14.9 microg/l, Māori 204.8 SEM 17.1 microg/l, Samoan 180.0 SEM 17.5 microg/l, p=0.58). IGF-I levels were similar between ethnic groups after adjustment (ANCOVA) for age, sex or BMI (p=0.5) or age, sex and fat mass (p=0.44). In multivariate analysis the only independent predictor of IGF-I was age (p<0.001) and explained 22% of the variance in IGF-I level.
  
  
  CONCLUSIONS
  Serum IGF-I concentrations were similar in Māori, Samoan and European population groups in New Zealand, despite significant differences in anthropomorphic variables and body composition.
authors.affiliation: Department of Medicine, University of Auckland, E-com House, 3 Ferncroft Street, Grafton, Auckland, New Zealand. w.bagg@auckland.ac.nz
authors.forename: W
authors.initials: W
authors.lastname: Bagg
authors.forename: J
authors.initials: J
authors.lastname: Aoina
authors.forename: P A R
authors.initials: PA
authors.lastname: Cross
authors.forename: G A
authors.initials: GA
authors.lastname: Whalley
authors.forename: G D
authors.initials: GD
authors.lastname: Gamble
authors.forename: R N
authors.initials: RN
authors.lastname: Doughty
authors.forename: I M
authors.initials: IM
authors.lastname: Holdaway
mesh_terms: D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D044465:White People / Q000208:ethnology
chemical_list: D007334:Insulin-Like Growth Factor I