Growth hormone treatment of osteoporotic postmenopausal women - a one-yearplacebo-controlled study

Objectives: To study the effect of 12 months of growth hormone (GH) treatme nt on bone markers, bone mineral density (BMD), lean body mass (LBM) and bo dy fat mass (BF) in postmenopausal osteoporotic women. Design: Sixteen patients were randomised to a double-blind randomised place bo-controlled one-year study with daily s.c. injections of GH or placebo. A fter the first year 14 patients (8 placebo treated, 6 GH treated) were recr uited to GH treatment during the second year. All patients were also supple mented with 0.5 g calcium per oral. Methods: Bone mineral density and body composition were assessed by dual en ergy X-ray absorptiometry. Biochemical bone markers were analysed by RIA or HPLC techniques. Diurnal GH profiles were performed with continuous venous blood sampling. Results: Sixteen patients started in the placebo-controlled study. In all, twelve patients completed one year and only four patients completed two yea rs of GH treatment. At baseline 3 patients had serum insulin-like growth fa ctor-I (S-IGF-I) levels below -2 S.D. for age. Maximal diurnal GH levels te nded to correlate negatively with S-IGF-I (P=0.076). S-IGF-I was unrelated to BMD. Serum TGF-binding protein-1 (S-IGFBP-1) correlated negatively with femoral neck BMD (r=-0.61, P=0.012). The intended GH dose of 0.05 U/kg/day or a maximum of 3 U/day s.c. was reduced to 0.024 +/- 0.004 U/kg/day equal to 0.5-2.7 U/day due to frequent side effects, and four patients were exclu ded. After one year of GH treatment BF increased slightly, LBM and BMD in t otal body and lumbar spine were unchanged but femoral neck BMD had decrease d 3.4 +/- 1.6% (P < 0.05). The mean S-IGF-I increase was 32% (range -38-138 %). Mean levels of the bone formation markers S-osteocalcin and S-procollag en type I propeptide increased maximally by 88 and 36% respectively after 9 -12 months while the bone resorption markers were unchanged. In the placebo -treated group there were no significant alterations. Conclusions: The effects on S-IGF-I, bone markers and LBM were small althou gh GH-related side effects were common. The reason for this apparent partia l resistance to the anabolic effects of GH is not clear but nutritional def icits may be involved. Assessment of the effects of GH on bone mass and fra cture rate requires longer study periods than one year.