Relationships between IGF-1 and IGFBP-1 and adiposity in obese African-American and Latino adolescents

Obesity (Silver Spring). 2011 May;19(5):933-8. doi: 10.1038/oby.2010.211. Epub 2010 Sep 30.

Abstract

The purpose of this study was to examine interrelationships between insulin-like growth factor 1 (IGF-1), IGF binding proteins (IGFBPs), and adiposity in 49 African-American and 77 Latino obese adolescents (15.3 ± 0.1 and 15.4 ± 0.2 years; BMI: 33.0 ± 0.7 and 35.0 ± 1.0 kg/m(2), respectively). Immunoradiometric assays were used to measure IGF-1, IGFBP-1, and IGFBP-3. Total fat and soft lean tissue were measured by dual-energy X-ray absorptiometry and visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue (SAAT), and hepatic fat fraction (HFF) were measured by magnetic resonance imaging. IGF-1 levels were 23.1% higher and IGFBP-1 were 40.4% higher in African Americans compared to Latinos after adjustment for total lean and total fat mass. IGF-1 and IGFBP-1 were inversely correlated with BMI, total fat mass, VAT, and HFF (r = -0.20 to -0.33, P < 0.05) while IGFBP-1 was inversely correlated with SAAT (r = -0.22, P < 0.05). These relationships did not differ by ethnicity, however, the relationship between IGF-1 and SAAT, as well as IGFBP-1 and HFF, differed by ethnicity. Predicted mean IGF-1 levels were 30.7% higher for African Americans at the 75th compared to 25th percentile of SAAT and only 11.7% higher for Latinos. Predicted mean IGFBP-1 levels were 158% higher for African Americans at the 25th compared to the 75th percentile of HFF while IGFBP-1 levels were 1.7% higher for Latinos at the 75th compared to the 25th percentile. These results demonstrate that the relationship between IGF-1 and SAAT as well as IGFBP-1 and HFF are different in African-American and Latino adolescents and may contribute to the higher IGF-1 levels in African-Americans.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Absorptiometry, Photon
  • Adipose Tissue / diagnostic imaging
  • Adipose Tissue / metabolism*
  • Adolescent
  • African Americans
  • Body Composition
  • Female
  • Hispanic Americans
  • Humans
  • Insulin-Like Growth Factor Binding Protein 1 / metabolism*
  • Insulin-Like Growth Factor I / metabolism*
  • Intra-Abdominal Fat / metabolism
  • Liver / diagnostic imaging
  • Liver / metabolism*
  • Male
  • Obesity / diagnostic imaging
  • Obesity / ethnology
  • Obesity / metabolism*
  • Puberty
  • United States / ethnology

Substances

  • Insulin-Like Growth Factor Binding Protein 1
  • Insulin-Like Growth Factor I