Bone mineral density and body composition in children with congenital adrenal hyperplasia.

OBJECTIVE: Children with congenital adrenal hyperplasia (CAH) are exposed to fluctuating cortisol and androgen levels. The effects these hormonal states have on bone mineral density (BMD) and body composition are not well studied. The study's objective was to compare BMD and body composition, including visceral adipose tissue (VAT) and Android:Gynoid (A:G) ratio, in children with CAH vs healthy age-matched, sex-matched and BMI-matched controls.

DESIGN: Total body BMD (TBMD) Z-scores were adjusted for height-for-age Z-scores (TBMDHAZ). Hydrocortisone dose (mg/m2/d) was averaged over the past year. Bone age Z-scores were used as a surrogate for long-term androgen exposure in cases. Statistical analyses comparing cases and controls accounted for matched groups using mixed linear models.

PATIENTS: Forty-two cases with CAH (average age 12.3 years [SE 3]; 17 males) and 101 controls underwent a dual-energy X-ray absorptiometry scan.

RESULTS: Children with CAH had lower TBMD (0.81 vs 1.27, P = .003) and TBMDHAZ Z-scores (-0.51 vs -0.01, P = .001) than controls. In CAH cases, TBMD and TBMDHAZ Z-scores were positively correlated with bone age Z-scores (r = .63, P < .0001; r = .51, P = .001, respectively) but were not associated with HC dose. VAT and the A:G ratio did not differ significantly between children with CAH and controls and neither was associated with HC dose.VAT was not associated with bone age Z-score.

CONCLUSION: Lower BMD was observed in CAH cases compared with controls although no differences in body composition were identified. Among CAH cases, increased chronic androgen exposure, as measured by bone age Z-scores, was associated with higher BMD but was not associated with VAT.