Effects of 10 years of growth hormone (GH) replacement therapy in adult GH-deficient men

OBJECTIVE: GH-deficient adults have changes in body composition, bone mineral density (BMD) and lipid profile that can be altered by GH substitution. However, long-term data on GH substitution (up to 10 years of follow-up) are limited. DESIGN: The effects of 10 years of GH replacement therapy on BMD, body composition, bone parameters, serum lipids and glucose metabolism were studied. PATIENTS: Twenty-three childhood-onset GH-deficient men (mean age at baseline 28.6 years) were studied during 10 years of GH substitution therapy. A group of 19 age-matched healthy men served as a control group for BMD measurements at baseline and after 10 years. RESULTS: BMD of the lumbar spine increased during the 10 years of GH therapy. Bone markers and BMD in the hip increased during the first 5 years of GH therapy, but were not different from baseline after 10 years. BMD changes over time in the lumbar spine and femoral neck were significantly different in the patients compared to the controls. After 10 years the difference between the groups had decreased, but BMD was still higher in the controls than in the patients. Lipid profile had improved after 10 years of GH therapy, but body mass index (BMI), waist-hip ratio (WHR), fasting glucose and glycosylated haemoglobin (HbA1c) had increased compared to baseline. CONCLUSIONS: This long-term follow-up study found that 10 years of GH substitution in GH-deficient men causes sustained improvements in BMD in the lumbar spine and lipid profile but not in body composition.