Effects of GH Therapy on Bone Mass in Childhood

Abstract

GH stimulates bone growth, but the effect of GH on bone mass in childhood remains unclear. In this study, we analyzed the effect of GH on bone mass during childhood by using dual energy X-ray absorptiometry (DXA). Seventy-two males and thirty-eight females with GH deficiency were investigated. Bone mineral density (BMD), bone mineral content (BMC) and the projected area of the lumbar spine (L2-4) were measured by DXA before (B), after one year (1T) and after two years (2T) of GH therapy. Volumetric BMD (vBMD) was calculated by using a cylindrical vertebral model. Both BMC and area increased during GH therapy both in male and female subjects, but the L2-4BMDZ scores did not show a significant change in either sex after two years of therapy (males: Zscore B: -0.782 ± 0.698 2T: -0.927 ± 0.785, females: B: -0.782 ± 0.698 2T: -0.927 ± 0.785). Since BMD is affected by bone size, the assessment of bone mass during growth periods required volume-adjusted data. The absolute vBMD value also stayed unchanged both in male and female subjects. Therefore GH stimulated bone growth with an appropriate increase in bone mass in GH deficient patients during childhood.