دانلود رایگان مقاله انگلیسی ویتامین D و عملکرد جنسی مردان: مطالعات عرضی و طولی - هینداوی 2018

Background. The effects of vitamin D on sexual function are very unclear. Therefore, we aimed at evaluating the possible association between vitamin D and sexual function and at assessing the influence of vitamin D administration on sexual function. Methods. We retrospectively studied 114 men by evaluating clinical, biochemical, and sexual parameters. A subsample (n = 41) was also studied longitudinally before and after vitamin D replacement therapy. Results. In the whole sample, after performing logistic regression models, higher levels of 25(OH) vitamin D were significantly associated with high values of total testosterone and of all the International Index of Erectile Function (IIEF) questionnaire parameters. On the other hand, higher levels of total testosterone were positively and significantly associated with high levels of erectile function and IIEF total score. After vitamin D replacement therapy, total and free testosterone increased and erectile function improved, whereas other sexual parameters did not change significantly. At logistic regression analysis, higher levels of vitamin D increase (Δ-) were significantly associated with high values of Δ-erectile function after adjustment for Δ-testosterone. Conclusions. Vitamin D is important for the wellness of male sexual function, and vitamin D administration improves sexual function.

4. Discussion

Our cross-sectional study shows that vitamin D levels are directly able to influence all sexual function parameters. Several transversal clinical studies have evaluated and confirmed the role of vitamin D in influencing sexual dysfunction. In this regard, the widest study has been conducted by Farag and colleagues who performed a cross-sectional analysis of a nationally representative sample of 3390 US men aged ≥ 20 years. They found that 25(OH) vitamin D levels were lower in men with, than in those without, erectile dysfunction. After adjusting for comorbidities, lifestyle variables, and medication use, those with 25(OH) vitamin D deficiency had a higher prevalence of erectile dysfunction compared to those with optimal levels [7]. Interestingly, similar to our results, their findings suggest that the link of 25(OH) vitamin D with erectile dysfunction is independent of testosterone [7]. Consistently, Barassi et al. evaluated fifty patients affected by erectile dysfunction and reported that those with severe/complete erectile dysfunction were more frequent in the group with vitamin D levels < 20 ng/mL as compared with those in the group with levels > 20 ng/mL. [6]. In addition, another study found that in a large cohort of type 2 diabetic subjects, patients with lower 25(OH) vitamin D levels (<10 ng/mL) showed higher penile intimamedia thickness and lower IIEF-5 score and cavernous peak systolic velocity compared to patients with 25(OH) vitamin D > 20 ng/mL. Also, 25(OH) vitamin D levels were directly correlated with IIEF-5, and, at multivariate analysis, 25(OH) vitamin D deficiency remained a predictor of erectile dysfunction independent of other confounding factors [5]. Furthermore, in a particular case series of 37 dialysis patients, the ASEX total score was found to be negatively correlated with serum 25(OH) vitamin D level, thus demonstrating that sexual dysfunction is related to low serum 25(OH) vitamin D levels [8]. Conversely, one clinical study denied this association. In fact, Bellastella and colleagues, by examining 122 male adults with type 2 diabetes (51 with associated hypogonadism and 71 with normal gonadal function), found that there was no correlation between the severity of erectile dysfunction and vitamin D levels [9].