Bone Abstracts

Objectives: Congenital adrenal hyperplasia (CAH) is a rare condition characterized by the inability of the adrenal gland to produce cortisol. The classical form is due to the deficit of 21-hydroxylase activity (21-OHD) and it accounts for 90–95% of all CAH cases. Treatment of CAH patients consists of life-long glucocorticoid therapy, which must be dosed carefully to avoid excessive or insufficient adrenal suppression. There are data showing low bone mineral density (BMD) in adult patients with CAH, particularly evident in male patients. Few data are available describing the bone mass situation in children. The objective of the current study was to describe bone mineral status in prepubertal CAH patients, and the evolution of their BMD measurements through puberty.

Methods: We enrolled 29 prepubertal children with the classical form of CAH (16 girls and 13 boys), aged 4.8–11.5 years at baseline. All patients were receiving cortisone as replacement therapy. We assessed BMD by dual-energy X-ray absorptiometry at the lumbar spine and the whole skeleton at enrollment, and after completion of the pubertal period. We compared BMD values of CAH patients with those of 116 healthy controls of comparable ages.

Results: At baseline lumbar spine BMD values of CAH patients (0.755±0.112 g/cm²) were not different from those of healthy controls. Similarly, whole body BMD measurements (0.902±0.139 g/cm²) did not differ from those of healthy subjects. After puberty we observed significantly lower BMD values of CAH patients both at the lumbar spine (1.162±0.133 g/cm², P<0.05), and in the whole skeleton (0.161±0.098, P<0.05). When BMD data were expressed as Z-scores, we could observe a mean decrement after puberty of −0.2 (1.1) in the lumbar spine, and of −0.7 (1.1) in the whole skeleton. The mean decrement in BMD Z-score of male patients was significantly larger than that of female patients in both skeletal sites.

Conclusions: Our data identify puberty as the critical period for the development of bone density impairment in CAH patients. It is therefore important to monitor closely the bone mass acquisition in relation to the replacement therapy during puberty to promote bone health in CAH patients.