The Relationship between Vitamin D and Basal Cell Carcinoma: A Systematic Review.

This systematic review studies the relationship between vitamin D serum levels and basal cell carcinoma (BCC). The primary source of vitamin D is sunlight exposure. Recently, an increase in the intake of vitamin D supplements has been noticed. The protective value of vitamin D is well established and has been studied several times for the health of the bones, cartilage, growth, various dermatological diseases, and also as a chemoprotective agent against several cancers. On the scientific front, it has yet to be established that increasing serum vitamin D levels increase the incidence of BCC. We included reports that investigated this relationship in this review. We applied keywords in published papers in PubMed, ScienceDirect, Cochrane, and Google Scholar to find relevant studies. After applying the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist and the quality appraisal for 68 records, we included only ten studies. In these studies, serum levels of vitamin D were measured. Five of them supported the link between BCC incidence and development and high serum vitamin D levels (e.g., Mahamat-Saleh Y, et al.), while the other five did not (e.g., Tang JY, et al.). We included only two studies that investigated the vitamin D receptor (VDR) polymorphism. Experts debate adding a high dose of vitamin D supplements to our daily routine. After studying most of the reports, it was ascertained that the literature supports keeping vitamin D serum levels below 30-60 nmol/L. However, further studies should be done to help find a healthy balance of vitamin D serum levels, especially when it comes to increasing the risk of cancer like BCC.