Effects of Adrenal Androgen Levels on Bone Age Advancement in Prepubertal Children: Using the Ewha Birth and Growth Cohort Study

Abstract

Bone age (BA) advancement in prepubertal children may be associated with earlier onset of puberty and obesity. This study aimed to define the effects of adrenal androgen levels on the advancement of BA in prepubertal children, independent of obesity. During July and August 2011, we examined BA in 200 prepubertal children aged 7-9 years who were part of the Ewha Birth & Growth Cohort Study. BA was assessed by the Greulich-Pyle method. An index of BA advancement was calculated as the ratio of BA to chronological age (CA) (BA/CA), and this ratio was classified into 3 tertiles. We analyzed the relationship between BA advancement and anthropometric characteristics and adrenal hormone levels. The number of overweight children increased from the first group to the third group (P(Trend) = 0.03). The levels of adrenal androgens showed a significant positive correlation with the tertile groups after adjusting for age and sex (testosterone: r = 0.26, P < 0.001; dehydroepiandrosterone: r = 0.21, P < 0.001; androstenedione: r = 0.20, P < 0.001). Further, after controlling for body mass index (BMI), sex, and age, the BA/CA was found to be positively correlated with androstenedione (β = 0.04, R² = 3.7%) and testosterone levels (β = 0.05, R² = 4.7%). Based on our results, it is suggested that adrenal androgen levels are associated with BA advancement independent of BMI.

Keywords: Adrenal Cortex Hormone; Bone Age; Children; Obesity.

Fig. 1

Association between BA/CA and adrenal androgen levels. Residual obtained from the regression model using BA/CA as the dependent variable and BMI, age, and sex as independent variables. These residual values were then used as dependent variables with log-transformed hormone concentrations as the independent variables in the regression model. The regression line indicates the linear association between (A) log-transformed androstenedione or (B) log-transformed testosterone levels and the BA/CA ratio residual. BA = bone age, CA = chronological age, BA/CA = bone age to chronologic age ratio, BMI = body mass index.