The influence of testosterone on the quality and bone mineral density in men

Background. The purpose of the study was to evaluate the effect of testosterone fractions on the mineral density and bone quality in men with different bone mineral density (BMD). Materials and methods. We have examined 72 men aged 40–89 years. They were divided into 2 groups depen­ding on BMD: main group — with low BMD (n = 39); control group — with age norm of BMD (n = 33). BMD, lean and fat masses were measured by the dual-energy X-ray absorptio­metry (DXA) method (Prodigy, GEHC Lunar, Madison, WI, USA). TBS iNsight® software (Med-Imaps, Pessac, France) was installed on our DXA machine to evaluate trabecular bone score (TBS) at the L1-L4. The levels of testosterone and sex hormone binding globulin (SHBG) were determined by electrochemiluminescent immunoassay. Results. It was found that men with low BMD have significantly lower indices of free testosterone and bioavai­lable testosterone, while the level of SHBG is significantly hig­her. In men with low BMD, a positive significant correlation was established between the index of free testosterone and BMD at the lumbar spine (r = 0.31; p = 0.05) and femoral neck (r = 0.32; p = 0.05). Conclusions. Free testosterone is a universal indicator that has a proven effect not only on the cortical and trabecular bone tissue, but also on the fat and lean mass.