Erection is a complex phenomenon which implies a delicate and coordinated equilibrium among the neurological, vascular, and the tissue compartments. Many clinical factors (e.g., age, cardiovascular risk, and smoking habit) are able to impair erectile function [1]. Vitamin D is mainly involved in the regulation of calcium/phosphorus homeostasis and bone health. However, animal and human studies also suggest an involvement of vitamin D in the pathogenesis of several endocrine diseases [2–۴]. In fact, vitamin D may have a role also in type 1 and type 2 diabetes mellitus, Addison’s disease, Hashimoto’s thyroiditis, Graves’ disease, and polycystic ovary syndrome [2–۴]. Some evidence also suggests a possible role for vitamin D in the regulation of sexual function. In particular, recent clinical works have suggested that low vitamin D levels may somehow be associated with the occurrence of sexual disturbances, especially erectile dysfunction [5–۸], even if not all the studies agree on this point [9]. These results need confirmation because of their potential revolutionary approach to the treatment of sexual dysfunction. To the best of our knowledge, only three works have assessed the effect of vitamin D supplementation on sexual function, showing different results [8, 10, 11]. In view of these considerations, in this retrospective research, we performed a transversal and a longitudinal study, aimed at evaluating both the association between vitamin D and sexual dysfunction and the possible effect of vitamin D supplementation on sexual function.

۲٫ Materials and Methods

۲٫۱٫ Subjects. 114 men [age: median 64.0 (interquartile range 60.7–۶۸٫۰)] who attended our andrology unit seeking medical care for sexual dysfunctions from 2003 to the present were retrospectively evaluated. Registration of patients who attended our andrology unit for sexual dysfunctions from 2003 to the present was retrospectively reviewed. The inclusion criteria were as follows: (1) absence of important systemic diseases, both previous and ongoing, apart from late-onset hypogonadism or type 2 diabetes mellitus, (2) availability of all the considered clinical and biochemical parameters, (3) sexual relationship since at least 1 year before the visit, (4) absence of previous investigation or treatment for sexual dysfunction, and (5) having carried out calcium metabolism assessment in the summer period (June–September) both at baseline and after treatment. The exclusion criteria were as follows: (1) ongoing pharmacological treatment for hypogonadism, (2) presence of endocrinological disorders other than late-onset hypogonadism or type 2 diabetes mellitus, (3) alcohol or drug dependence, and (4) psychiatric diseases.