The Influence of Age, Alcohol Consumption, and Body Build on Gonadal Function in Men*

Abstract

Basal plasma levels of testosterone, dihydrotestosterone, estradiol, and gonadotropins and testosterone-binding capacity (percent radioactive testosterone bound to protein) were measured in healthy carefully screened young (31–44 yr old; n = 44) and older (64–88 yr old; n = 42) male participants in the Normative Aging Study of the V.A. There was no statistically significant effect of age on testosterone [younger group, 4.16 ± 0.27 (SEM) ng/ml; older group, 4.62 ± 0.32 (SEM) ng/ml] or the free testosterone index [younger group, 2.05 ± 0.14 (SEM) ng/ml; older group, 1.76 ± 0.11 (SEM) ng/ml]. The testosterone-binding capacity was higher in the older group (younger group,50.10 ± 1.18% (SEM); older group, 60.10 ± 1.18% (SEM); P < 0.001). Of the two products of testosterone metabolism studied, estradiol did not change with age,while dihydrotestosterone was lower [younger group, 0.25 ± 0.02 (SEM) ng/ml; older group, 0.20 ± 0.01 (SEM) ng/ml; P = 0.03] in the older group. FSH levels were increased among the older men [older group, 92.9 ± 6.0 (SEM) ng/ml; younger group, 61.1 ± 5.0 (SEM) ng/ml; P < 0.001]. LH levels were not significantly influenced by age. There was no effect of level of chronic stable alcohol intake on gonadal function, as estimated by testosterone levels and the free testosterone index. Analysis of the relationship between body build and hormone levels indicated that estradiol levels were highest in gynandromorphic men and lowest in mesomorphic men.