Bone mineral content and androgen-estrogen activity in a population of healthy male inhabitants of Wroclaw, Poland

Abstract

In this study, age-related changes in bone mineral content (BMC) were investigated in the context of alterations of total testosterone, estradiol and dehydroepiandrosterone sulfate (DHEAS) during normal male aging. An anthropologically homogeneous group of 236 males, aged 22–67 years, was subdivided into eight 5-year age categories. The men were healthy and occupationally active inhabitants of the city of Wroclaw, Lower Silesia, Poland. The investigated hormones were measured using standard immunoassays. Trabecular, cortical and total BMC at the distal radius of the non-dominant hand were separately assessed by peripheral quantitative computed tomography (pQCT) using the Stratec 960 apparatus. All correlations among hormone and densitometric parameters and age were evaluated by use of non-parametric statistics (Spearman coefficient). Reductions in trabecular, cortical and total BMC of approximately 40.0%, 28. 1%and 30.8%, respectively, were found in the peak mass between the age category with maximal BMC values and men aged 55 years and older. The declines in trabecular and total BMC with age appeared to be statistically significant, whereas no analogous correlation between cortical BMC and age was found. We observed a decrease in total testosterone, DHEAS and estradiol levels of approximately 45%, 55% and 32%, respectively, in the maximal concentrations between the age category with peak values and men aged 55 years and older. A distinct decline in hormone levels commenced around 25 years of age. All evaluated steroids demonstrated a significant reduction with age. In our findings, the total testosterone level did not correlate at all with either trabecular, cortical or total BMC at the distal radius. DHEAS levels appeared to be insignificant for mineralization of cortical BMC, whereas a significant correlation was demonstrated between DHEAS and both total (r = 0.18; p = 0.02) and trabecular BMC (r = 0.22; p = 0.003). The last association was the strongest relationship established in the entire study. Estradiol levels, but not total testosterone values, appeared to correlate with all trabecular (r = 0.16; p = 0.02), cortical (r = 0.14; p = 0.04) and total BMC (r = 0.16; p = 0.02) at the distal radius. Total testosterone levels appeared to be insignificant for the degree of age-related changes in male bone mineralization. From the three sex steroids measured in healthy males, the adrenal androgen (dehydroepiandrosterone sulfate) seems to be the best endocrinological measure of the degree of male skeletal mineralization, especially of the trabecular component, which is clearly the most sensitive to all hormonal fluctuations. However, BMC is traditionally associated with gonadalfunctions, and is not always monitored reliably by total testosterone levels (and by concentrations of estradiol, which is usually converted peripherally from testosterone).