Association between serum vitamin D levels and prostate tumor: a systematic review and meta-analysis

Introduction: Prostate cancer is among the most frequent neoplasms of the male reproductive system, and its relationship with serum vitamin D level is a controversial subject. The present study intended to investigate the relationship between serum vitamin D levels and the risk of prostate carcinoma. Materials and Methods: This study is a systematic review and meta-analysis based on the PRISMA tool. The search was conducted in databases Web of Science, Cochrane, ProQuest, PubMed, and Google Scholar Search Engine until December 1, 2023. Data was analyzed using STATA 14 software. Results: There was no significant relationship between serum vitamin D levels lower than 50 nmol/L (vitamin D level <50 nmol/L) and prostate cancer. In Finland, the risk of prostate carcinoma in male individuals with serum vitamin D levels lower than 50 nmol/L was 34% higher (OR: 1.34, 95% CI: 1.14, 1.54). In South Korea, on the other hand, serum vitamin D levels lower than 50 nmol/L prevented prostate cancer (OR: 0.94, 95% CI: 0.90, 0.99). There was no significant relationship between the serum vitamin D levels lower than 50 nmol/L and prostate neoplasm in men aged 60 to 69 years old (OR: 0.95, 95% CI: 0.83, 1.07), in men 50 to 59 years old. On the other hand, serum vitamin D levels lower than 50 nmol/L increased the risk of prostate tumor by 32% (OR: 1.32, 95% CI: 1.13, 1.55). Furthermore, no significant relationship was observed between serum vitamin D levels higher than 50 nmol/L (vitamin D level >= 50 nmol/L) and the risk of prostate cancer (OR: 1.06, 95% CI: 0.99, 1.14). Conclusion: Generally, there was no significant relationship between serum vitamin D levels and the risk of prostate carcinoma; however, the relationship in some subgroups was statistically significant. We therefore recommend conducting additional studies on this subject.