Association Between Serum Vitamin D Concentration with Spermiogram Parameters and Reproductive Hormones Among Infertile Iranian Males: a Cross-sectional Study.

Infertility is a health concern affecting more than 186 million people globally, and male factors play a role in almost half of cases. Recently, the possible impact of vitamin D on male reproduction has become the center of attention. Our study intended to assess the correlation between serum vitamin D concentrations with sperm parameters and sex hormones in infertile Iranian men compared to fertile men. This cross-sectional study was performed among the 114 couples who were referred to the Urology Clinic of Imam Reza hospital in Mashhad, Iran. According to the inclusion criteria, 57 patients were entered into the infertility group, and 57 cases entered into the fertile group. Semen quality assessment was performed based on WHO guidelines, and the serum was analyzed for 25-hydroxy vitamin D, LH (luteinizing hormone), FSH (follicle-stimulating hormone), and testosterone by ELISA method. Vitamin D level was significantly higher in the fertile group compared with infertile males (p < 0.001). Moreover, vitamin D level was positively correlated with some fertility indicators assessed by spermiogram test including sperm motility (p < 0.001, r = 0.483) and sperm count (p = 0.019, r = 0.216). Additionally, vitamin D was positively associated with testosterone level (p = 0.025, r = 0.210). There was no significant correlation between vitamin D concentrations with sperms morphology, LH, and FSH level. Our study showed a significantly lower vitamin D level in infertile males compared to the fertile group. In conclusion, our study results showed a positive correlation between serum vitamin D with sperm motility, sperm count, and serum testosterone level in fertile males compared to infertile men and suggest the beneficial effects of vitamin D on male reproduction.