Background: Although vitamin D receptor (VDR) is expressed in human sperm, little is known about the role of vitamin D (Vit. D) in male reproduction. Our objective was to assess Vit. D levels both in serum and seminal fluid and to establish the relation between serum and seminal Vit. D levels, semen parameters, male sex hormones and serum calcium level in Egyptian infertile men. Patients and Methods: We conducted a prospective case control study including 30 healthy fertile males as a control group and 60 male patients with infertility of unknown etiology. Semen samples were collected and semen parameters were evaluated. Also, seminal Vit. D level was measured. Blood samples were taken as serum levels of Vit. D, calcium, testosterone, Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) were estimated. Results: There was significant decrease of both serum and seminal Vit. D level in groups of male infertility compared to control group. A significant positive correlation was found between serum and seminal Vit. D levels in different study groups. Also, significant positive correlation between serum Vit. D level and non-progressive sperm motility. Conclusion: Our results support the role of Vit. D in semen parameters and male fertility status.
