Bone mineral density, bone turnover markers, lean mass, and fat mass in Egyptian children with congenital adrenal hyperplasia

Introduction: Aim of this paper is to assess bone mineral density (BMD) and body composition, by dual energy X-ray absorptiometry (DXA), and various markers of bone growth, in a group of children with congenital adrenal hyperplasia (CAH) on long-term glucocorticoid therapy.
Material and methods: A case-control study included thirty patients with CAH with different states of metabolic control. Their mean age was 7.5 ±4.2 years. All patients are subjected to BMD using DXA at the neck of the femur and lumbar spine. A blood sample was taken for assessment of osteocalcin, osteoprotegerin, and procollagen type 1, as markers of bone formation, as well as RANKL and urinary deoxypyridinoline (DPD), as markers of bone resorption.
Results: We found no difference in BMD in patients and control subjects; however, patients showed significantly lower serum osteocalcin (p = 0.008) and osteoprotegerin (p = 0.0001) and significantly higher serum RANKL levels (p = 0.0001). Our results show that patients had significantly lower lean body mass (p = 0.005) and fat/lean ratio (p = 0.008) compared to matched controls. The duration of treatment showed a significant negative correlation with procollagen type 1 (r = –0.49, p = 0.02) and lean mass % (r = –0.43, p = 0.04); however, it showed a significant positive correlation with total fat mass % (r = 0.6, p = 0.0006), and fat/lean ratio (r = 0.43, p = 0.04). Dose of steroid had a significant positive correlation with BMI SDS (r = 0.4, p = 0.02).
Conclusions: Bone mineral density is normal but bone turnover is low in patients with CAH. There is an increase in fat/lean mass in patients with CAH.