Adult growth hormone deficiency and bone mass.

Bone mineral density (BMD) is reduced in adults with growth hormone (GH) deficiency and the decrease in BMD appears more marked if the GH deficiency is childhood onset rather than adult onset. Recent epidemiological studies suggest an increased fracture rate in GH-deficient adults. The skeletal response to GH therapy depends on the variety of GH deficiency, the type of bone studied and the duration of therapy. In the childhood-onset, GH-deficient adult there is either no change or a reduction in cortical and integral bone mass over the first 6 months, whereas at 6 months there is an increase in vertebral trabecular BMD. Subsequently there is a steady rise in BMD at all sites over the next 12-18 months. In the adult-onset, GH-deficient adult, the long-term results are more contentious. It is too early to determine whether GH therapy modifies fracture risk.