Ethnic differences in androgens, IGF-I and body fat in healthy prepubertal girls

J Pediatr Endocrinol Metab. 2000 May;13(5):497-503. doi: 10.1515/jpem.2000.13.5.497.

Abstract

Objective: To examine ethnic differences in adrenal androgen production, IGF-I, and IGFBP-1 and -3 in relation to bone age, insulin, and body composition in healthy prepubertal girls.

Methods: Serum levels of DHEA-S, androstenedione, IGF-I, and IGFBP-1 and -3 were examined in relation to bone age, insulin, and body composition (determined by dual-energy X-ray absorptiometry) in 47 (19 Caucasian, 9 African-American, 19 Mexican-American) healthy prepubertal girls aged 7.5-9.0 years.

Results: Age, weight, height, bone age, androstenedione, insulin, glucose:insulin ratios, and IGFBP-3 levels were not statistically different among groups. Mexican-American girls had higher % body fat than African-Americans or Caucasians (P < 0.001). DHEA-S levels in African-Americans were twofold higher than in Caucasians (P = 0.024), although their % body fat was not significantly different (16.1% and 19.4%, respectively; P = 0.138). DHEA-S levels in Mexican-American girls were intermediate. Bone age and weight were significant covariates for DHEA-S levels. Plasma IGF-I levels were also higher in African-American than in Caucasian or Mexican-American girls (P = 0.009). Covariance analysis showed that IGF-I levels were influenced mainly by ethnicity (P = 0.009) and were independent of bone age. Despite similar insulin levels among groups, IGFBP-1 levels were higher in Caucasians than in Mexican-Americans or African-Americans (P < 0.001).

Conclusions: In healthy prepubertal girls, DHEA-S concentrations are higher in African-Americans than in Caucasians or Mexican-Americans, even before any clinical evidence of adrenarche. Furthermore, IGF-I concentrations are higher in African-American girls than in Caucasian or Mexican-American girls which may contribute to the higher DHEA-S levels observed. Conversely, higher DHEA-S and IGF-I levels in African-American girls may be indicative of an influence not only of gonadal but also of adrenal androgens on the GH/IGF-I axis.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adipose Tissue / anatomy & histology*
  • African Continental Ancestry Group*
  • Age Determination by Skeleton
  • Androstenedione / analysis*
  • Child
  • Dehydroepiandrosterone Sulfate / blood*
  • European Continental Ancestry Group*
  • Female
  • Humans
  • Insulin-Like Growth Factor Binding Protein 1 / blood
  • Insulin-Like Growth Factor Binding Protein 3 / blood
  • Insulin-Like Growth Factor I / analysis*
  • Mexican Americans*
  • Puberty / physiology*

Substances

  • Insulin-Like Growth Factor Binding Protein 1
  • Insulin-Like Growth Factor Binding Protein 3
  • Androstenedione
  • Dehydroepiandrosterone Sulfate
  • Insulin-Like Growth Factor I