Changes in body composition, and endocrine and metabolic functions in healthy elderly Chinese men following Growth Hormone therapy

Abstract

Background An age-related decline in growth hormone (GH) level has been established, and this decline is associated with changes in body composition as well as a general increase in susceptibility to illness and a reduced sense of well-being. The current study, a first in Asia, sought to examine the effects of GH therapy on body composition and other endocrine and metabolic functions in a group of healthy elderly Chinese men. Methods A total of 23 healthy elderly Chinese men, aged between 60 and 69 years, were injected subcutaneously, three times weekly, with 0.08 U/kg of recombinant GH for 6 months. Various hormones and biochemical parameters, together with percentage lean body mass and body fat, were measured before, 3 and 6 months after the start and 3 months after the cessation of GH therapy. Results A significant increase in lean body mass, up to 9.1% over baseline values at 3 months post-therapy, and a significant decrease in body fat, up to 3.1%, were noted. GH therapy also induced variable and significant increases in levels of insulin growth factor (IGF-I), dehydroepiandrosterone sulfate (DHEAS), insulin, triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) and triglyceride and significant reductions in glucose and sex hormone binding globulin (SHBG) levels. No changes in testosterone, free androgen index and cholesterol were noted. A significant and independent correlation was noted between IGF-I and insulin, TSH, DHEAS, glucose and triglyceride levels. Conclusions GH augmentation therapy was effective in improving the body composition of a group of elderly Chinese men. GH-induced positive changes in body composition in the elderly were probably a result of the direct effect of the GH. It is also possible that some of the changes were mediated through GH-induced changes in thyroid hormones, insulin, glucose, triglyceride and DHEAS. However, the mechanism of GH- induced changes in body composition remains to be defined.