Background: A deficiency of Vitamin D not only causes poor bone mineralization but also has been implicated in many other chronic diseases.  Recent studies have suggested a relevance of vitamin D to reproductive physiology. Moreover, recent evidence is establishing to support the hypothesis that vitamin D status may contribute to the development of metabolic disturbances in PCOS. Aim of the Study: To  investigate the relationship between Vitamin D level and polymorphisms related to metabolic disturbances particularly Insulin resistance in women with PCOS. Methods: A review of the scientific literature (PubMed Search 1960 to 2017) Pubmed,  Embase and CENTRAL were searched to identify randomized controlled trials that investigated The Correlation between Depression and Folate Deficiency as the primary outcome. Identification of papers and data extraction  were performed by two independent researchers. We searched for relevant trials in the Cochrane Library, MEDLINE (from 1960), Embase (from 1960), and ongoing trial databases; all searches current to October 2017. Results: Eight studies were included enrolling 1225 women; 779 patients with depression and 446 control subjects. Univariate regression analyses of the weighted means indicated a significant correlation between vitamin D and IR predictability in both PCOS and control women. However, the significance was neutralized after factoring BMI in PCOS women. Conclusion: There is a growing body of evidence suggesting an inverse association between vitamin D status and metabolic disturbances in PCOS in the current literature yet heterogeneity of the conducted studies made it difficult to come out with a solid conclusion. Nevertheless, normalization of vitamin D levels is recommended generally and especially for PCOS patients.