Serum IGF-I levels are similar in Samoan, Maori and European populations despite differences in body composition

Objective: To determine if serum IGF-I concentrations are similar in healthy adult subjects from the Samoan, Maori and European populations in New Zealand. Design: Serum IGF-I concentration was measured in 75 healthy adults., aged 18-50 years, of Samoan (n = 23), Maori (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 Maori 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 ug/l, Maori 204.8 SEM 17.1 ug/l, Samoan 180.0 SEM 17.5 ug/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 Maori, Samoan and European population groups in New Zealand, despite significant differences in anthropomorphic variables and body composition. (c) 2005 Elsevier Ltd. All rights reserved.