Aim: Growth hormone (GH) plays an important role in the regulation of body composition and metabolism. GH deficiency is associated with obesity and hypercholesterolemia, which respond to GH treatment. In this study we evaluated changes in body composition and cholesterol profiles after discontinuation of GH therapy to assess atherogenic risk factors in GH-deficient patients.
Methods: We studied 18 male patients with GH deficiency 17-20 years of age at the time of discontinuing GH therapy. Body composition and cholesterol were measured 6 months before discontinuation of GH therapy with a weekly dose of 0.5 IU/kg (approximately 0.19 mg/kg), and immediately, 2 months, and 6 months after the end of GH therapy.
Results: Two months after termination of GH therapy the percentage of body fat and fat mass increased from 7.4% to 9.4% and from 3.8 kg to 5.0 kg, respectively, and remained high thereafter. Lean body mass decreased gradually, but the change was not significant. Lean body mass: fat mass ratio decreased from 14.7 at termination of GH therapy to 10.9 at the end of study. Total cholesterol (TC) showed a significant linear increase from 156 mg/dl immediately after discontinuation to 169 mg/dl 6 months after discontinuation of GH, whereas high-density lipoprotein cholesterol (HDLC) showed no change during the study. The TC to HDLC ratio showed a slight but insignificant trend toward an increase. There were no significant changes in any variables during the last 6 months of GH therapy.
Conclusion: GH therapy in patients with GH deficiency can reduce risk factors for obesity-related diseases and atherosclerosis. These beneficial effects are reversed after discontinuation of GH therapy. Further long-term studies of the effects of the GH withdrawal on lipid profiles, adiposity and life expectancy must be performed.