The relationship between indices of muscle function and circulating anabolic hormones in healthy elderly men

Abstract

The secretion of insulin-like growth factor-I and sex hormones declines with age. These changes are paralleled with the age-related decrease in muscle mass and muscle function. The aim of this study was to determine whether serum insulin-like growth factor-I (IGF-I) and sex hormone (binding globulin) levels (testosterone, estradiol, dehydroepiandrosterone sulfate and sex hormone binding globulin (SHBG) are associated with physical performance measurements (isometric knee extension and hand-grip strength, leg extensor power and functional mobility (timed ‘Up and Go’ test)) in healthy elderly men. Thirty healthy, independently living males (mean age 70 years, range 65–80) entered this cross-sectional study. Serum IGF-I and sex hormone (binding globulin) levels were not associated with muscle strength and power. A significant association between a good performance on the timed ‘Up and Go’ test (controlled for age, height and body mass index) and higher serum levels of SHBG (r = -0.43, p = 0.035) was found. Although caution is needed because of the small sample size in this study, we tentatively conclude that men with higher serum levels of SHBG perform better on the timed ‘Up and Go’ test.