Endocrine Abstracts

Context: The effect of GH replacement in elderly GH deficient (GHD) adults on bone mineral density (BMD) is not known.

Objective: In this prospective, single-centre, open-label study, the effects of 3-year GH replacement were determined in 45 GHD adults above 65 years of age and in 45 younger GHD patients with a mean age of 39.5 (S.E.M. 1.1) years. All patients had adult onset disease and both groups were comparable in terms of number of anterior pituitary hormonal deficiencies, gender, body mass index (BMI), and waist:hip ratio. BMD was measured using dual energy X-ray absorptiometry (DXA).

Results: The mean maintenance dose of GH was 0.24 (0.02) mg/day in the elderly patients and 0.33 (0.02) mg/day in the younger GHD patients. At baseline, absolute values of total body and lumbar (L2–L4) spine BMD were similar in both study groups whereas femur neck BMD was lower in the elderly as compared to the younger patients (0.91 (0.02) vs 1.02 (0.02) g/cm²; P<0.01). However, in the elderly GHD patients, z-scores at baseline were approximately zero. After 3 years of GH replacement, total body BMD was unchanged compared to baseline in both study groups. The 3-year GH replacement significantly increased lumbar (L2–L4) spine BMD and femur neck BMD by 4 and 2%, respectively, in the elderly patients and by 5 and 3%, respectively, in the younger patients. There were no statistical differences between groups in the treatment responses. At study end, femur neck BMD was still lower in the elderly patients.

Conclusions: This study shows that GH replacement increases lumbar (L2–L4) spine and femur neck BMD in elderly adults with adult onset GHD. This supports that GH replacement is useful in elderly GHD patients.