Correlations between serum testosterone, estradiol, and sex hormone-binding globulin and bone mineral density in a diverse sample of men

Context: The relationship between hormones and bone mineral density (BMD) in men has received considerable attention. However, most studies have been conducted in homogenous populations, and it is not known whether differences in hormones impact racial and ethnic differences in BMD. Objective: Our objective was to examine associations of testosterone, estradiol, and sex hormone binding globulin (SHBG) with BMD in a racially and ethnically diverse population. Design: This was a population-based, observational survey. Participants: A total of 976 Black, Hispanic, and white randomly selected men ages 30-79 yr from the Boston Area Community Health/Bone Survey were included. Outcome: BMD at the hip, wrist, and spine were calculated. Results: The mean age of the sample was 46.7 +/- 12.4 yr. BMD levels were highest in black men, followed by Hispanic and then white men. Associations between hormones and BMD were consistent across racial and ethnic groups. Total and free testosterone was not correlated with BMD in age-or multivariate-adjusted models. SHBG was inversely correlated with total hip and ultra-distal radius BMD after age adjustment, but not with multivariate adjustment for age, lean mass, fat mass, physical activity, self-rated health, and smoking. Total and free estradiol levels were positively and significantly correlated with femoral neck and total hip BMD, even with multivariate adjustment (partial correlations ranged between 0.11 and 0.16). However, estradiol levels failed to account for racial and ethnic differences in hip BMD. Conclusions: In our diverse population, neither serum total nor free testosterone levels were associated with BMD. Correlations between BMD and estradiol were significant but did not appear to account for any of the observed racial and ethnic differences in BMD. These findings suggest that differences in hormone levels are not a major contributor to the observed differences in BMD between Black, Hispanic, and white men.