The effects of glucocorticoid replacement therapy on growth, bone mineral density, and bone turnover markers in children with congenital adrenal hyperplasia.

Even with current so called physiologic doses of glucocorticoid replacement therapy, children with congenital adrenal hyperplasia (CAH) often show relative short stature and delayed bone maturation, an observation that suggests possible long-term effects on bone metabolism of daily transient post-absorptive hypercortisolemia. In 28 patients with 21-hydroxylase or 17 alpha-hydroxylase deficiency (16 females and 12 males, ages 4.9-22 yr) who had received oral cortisol 10-15 mg/M2/day for 4.7-22 yr, we studied cortisol bioavailability, growth, bone maturation, vertebral bone mineral density, and various markers of bone formation and resorption. Patients were grouped according to mean on-therapy serum 170H-progesterone or progesterone levels as tight control (170HP < 10 nmol/L), fair control (170HP 10-40 nmol/L or progesterone 1.0-1.5 nmol/L), or poor control (170HP > 40 nmol/L). There was no difference in peak post-absorptive serum cortisol or area under the concentration-time curve, and only three patients had a peak serum cortisol of more than 700 nmol/L. There was no difference in present height Z-score (-0.96; -0.24; -0.6), height Z-score at age 2 yr (-1.5; +0.4; -1.3), or current growth velocity Z-score (-0.1; +1.2; -2.2) between the groups, but bone maturation Z-score was significantly delayed (-1.63) in the tight control group and advanced (+0.8) in the poor control group. Present height was highly correlated (r = 0.8) with height at age 2 yr. Serum calcium, phosphorus, alkaline phosphatase, parathormone, and 25OH-vitamin D levels were all normal. There was no difference between the groups in age-corrected vertebral bone mineral density, and no difference in serum osteocalcin, procollagen peptide, or collagen C-terminal telopeptide, nor in urinary amino-terminal telopeptide. The data suggest that current methods of cortisol replacement do not significantly influence bone formation, resorption or density during childhood and therefore should not contribute to adult osteoporosis. The possibility remains that hypercortisolemia during infancy produces the short stature and delayed bone maturation that are present by the age 2 yr.