Low serum zinc concentration is associated with low serum testosterone but not erectile function

To investigate the relation between serum zinc concentration and several factors, including serum testosterone concentration and the score of questionnaires on sexual function in patients with sexual problems.

This study comprised 720 men (age, 46.3 [21-83] years) with some kind of sexual problem. Age, scores of the Sexual Health Inventory for Men and the Erection Hardness Score, and endocrinologic data including serum concentrations of testosterone, prostate-specific antigen, and zinc were included in this study. After serum zinc concentration of the men was classified into 5 groups (<70, 70≤ <80, 80≤ <90, 90≤ <100, ≤100 μg/dl), the relation of each parameter with serum zinc concentration was assessed for a trend analysis. Finally, the relation between serum concentrations of zinc and testosterone as well sexual function evaluated by the scores of the questionnaires was investigated.

Only serum testosterone concentration (ptrend = 0.028) and serum cortisol concentration (ptrend = 0.003) showed a statistically significant relation to serum zinc concentration by trend analysis. Interestingly, trend analysis between serum concentrations of testosterone and zinc still showed a significant association after adjustment for serum cortisol concentration (ptrend = 0.032). However, no significant association was found in the relation between serum zinc concentration and the scores of the questionnaires after adjustment for serum concentrations of testosterone and cortisol.

We clearly showed that after adjustment for serum cortisol concentration by trend analysis, serum testosterone concentration decreased as serum zinc concentration decreased, although sexual symptoms were not associated with this decrease.