Sex hormone-binding globulin, estradiol, and bone turnover markers in male osteoporosis

Abstract

The role of estrogen deficiency in male osteoporosis is still under discussion. One hundred five subjects, 65 of them suffering from osteoporosis (mean age, 53.9 years) and 40 age-matched controls were studied. Osteoporosis was defined by a T score 0.05), and the relationship between estradiol levels and BMD at the femoral neck was weak (r = 0.25, P < 0.05). On the other hand, SHBG was significantly higher in the osteoporotic patients than in controls (P < 0.01). This difference persisted after adjustment for body mass index (BMI) and after exclusion of patients with a condition known to increase SHBG levels. Moreover, this carrier protein was negatively correlated with BMD at the femoral neck (r = -0.37, P < 0.01) and at the lumbar spine (r = -0.27, P < 0.05). SHBG also correlates strongly with sCTX (r = 0.37, P < 0.01). Finally, logistic regression analysis showed that serum SHBG concentration was significantly associated with the presence of fractures; the odds ratio of having a fracture was 2.04 [95% confidence interval (CI) 1.2-3.4, P < 0.01] for each increase of 1 standard deviation (SD) in the patient's SHBG level. The stronger relationship was nearly the same for the whole group and for patients with idiopathic osteoporosis. This study therefore suggests that SHBG may play a key role in male patients with idiopathic or secondary osteoporosis. It shows that serum SHBG concentration is increased in middle-aged men with osteoporosis and is correlated with hip, spine BMD,…