Luteinizing hormone, testosterone and inhibin B levels in the peripubertal period and racial/ethnic differences among boys aged 6-11 years: analyses from NHANES III, 1988-1994

P>Objective To determine whether the initial physical findings of puberty are accompanied by hormonal evidence of pubertal activation of the hypothalamic-pituitary-gonadal (HPG) axis and whether racial/ethnic differences exist, we have analysed hormone levels in relation to age, onset of puberty and race/ethnicity. Design Cross-sectional analysis of luteinizing hormone (LH), testosterone (T) and inhibin B from banked sera from a representative sample of US boys aged 6 center dot 0-11 center dot 99 years who participated in the National Health and Nutrition Examination Survey (NHANES) III. Patients Eight hundred and twenty-eight boys having sera including 228 non-Hispanic white (NHW), 266 non-Hispanic black (NHB), 288 Mexican-American (MA) and 46 'other'. Measurements Using analysis of variance and linear regression techniques, concentrations of LH, T and inhibin B were compared by race/ethnicity for all boys and pubertal status (Tanner's Staging 1, 2 and 3+) for boys aged 8 years and older. Receiver operating curves were utilized to identify cut-points predictive of pubertal HPG status. Results Mean hormones levels progressively increased with age. Receiver operating characteristic (ROC) curves indicate hormones are consistent with pubertal onset as indicated by Tanner stage 2, except for T and genital stage 2. Inhibin B and LH levels increased significantly by genital stage after adjusting for age and race/ethnicity, while LH and T concentrations increased significantly across pubic hair stages. Levels of inhibin B were significantly higher for NHB boys compared with other racial/ethnic groups. Conclusions In these cross-sectional findings, hormone levels rise gradually as boys approach the peripubertal age, whereas an abrupt rise was not associated with the onset of physical changes of puberty.