REDUCED BONE-MINERAL DENSITY IN ADULTS WITH GROWTH-HORMONE (GH) DEFICIENCY - INCREASED BONE TURNOVER DURING 12 MONTHS OF GH SUBSTITUTION THERAPY

To evaluate the consequences of growth hormone (GH) deficiency on bone mineral density and to evaluate the effects of GH substitution therapy, 68 adults (25 females and 43 males) aged 22-61 (mean 44.2 +/- 1.2) years with GH deficiency (GHD) were studied, Fifty-eight patients had panhypopituitarism, three had isolated GHD and in seven patients at least one additional pituitary function was affected. Twenty-one patients had childhood onset GHD, The patients were randomized to receive either GH in daily injections (0.125 IU . kg(-1). week(-1) for the first 4 weeks and subsequently 0.25 IU . kg(-1). week(-1)) or placebo for 6 months, The trial continued as an open study with GH treatment for 6 or 12 months, with data presented as compiled data of 12 months of GH treatment in 64 patients. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry and bone turnover was assessed by serum markers of bone metabolism (osteocalcin, procollagen I peptide, crosslinked telopeptide of type I collagen and alkaline phosphatase activity), In women with adult onset GHD (N = 19) and in men with childhood onset GHD (N = 15), total body, spine and hip BMD was significantly reduced at baseline compared to Swedish age- and sex-matched control material. In men with adult onset of GHD (N = 28), BMD did not differ from male controls, During the placebo-controlled period, GH induced decreased total body and spine BMD, probably due to an expansion of the remodelling space, whereas all serum markers of bone turnover increased. Compiled GH data showed similar results after 6 months of treatment. After 12 months of GH treatment, BMD did not differ from basal values except for total body BMD, which was lower, whereas the serum markers of bone metabolism were still increased as compared to basat values. Two-thirds of the patients experienced fluid retention with peripheral oedema and arthralgias on the higher GH dosage. One obese patient developed non-insulin-dependent diabetes mellitus and was withdrawn from the study. These results demonstrate that GHD has negative effects on BMD and that GH substitution induces increased bone turnover. Continued long-term observations will reveal if there is a positive effect of GH substitution on bone mass in the adult GHD patient.