Studies on bone mineral metabolism in congenital adrenal hyperplasia Part II Serum osteocalcin level: Its relation to linear growth and skeletal maturation

Abstract

A study was carried out to examine whether the level of serum osteocalcin (OC) reflects the response of bone growth to treatment in patients with congenital adrenal hyperplasia (CAH) in six prepubertal girls (21-hydroxylase deficiency) treated with hydrocortisone 13–33mg/m2/day and fludrocortisone 0.05–0.1mg/day. The relationships between biochemical parameters including serum OC, plasma testosterone, insulin-like growth factor I and 17-hydroxyprogesterone, with linear growth velocity SD score for chronological age and rate of skeletal maturation (ratio of bone age to chronological age) were serially assessed at three or over month intervals for three years. The statistically most significant correlation was found between OC level and growth velocity (r=0.55, p<0.001), compared with the levels of testosterone (r=0.45, p<0.05), 17-hydroxyprogesterone (r=0.33, p=0.053) and insulin-like growth factor I (r=0.10). In each patient, the serum OC level seemed to change in accordance with the growth velocity and the rate of skeletal maturation; a rise in OC level indicate an increased growth velocity with skeletal maturation, and a reduction of OC indicated the reverse. These OC responses were thought to be influenced by treatment condition (under/overtreatment). It may be that fluctuations in the level of serum OC are an indicator of the responses of bone to treatment in CAH.