Lack of association between the risk of prostate cancer and vitamin D receptor polymorphism: a meta-analysis of 27 published studies.

Background: The association between vitamin D receptor gene (rs1544410) polymorphism and prostate cancer (PCa) risk has been investigated by numerous previous studies, which yielded inconsistent results. We conducted this meta-analysis to derive a relatively precise description of this association.

Methods: All studies published up to December 2017 were identified via a systematic search of PubMed, Embase, and China National Knowledge Infrastructure databases. Pooled odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated to describe the strength of the relationship between and PCa risk.

Results: In this meta-analysis, 27 studies with 9,993 cases and 9,345 controls were included. The pooled results revealed that polymorphism was not associated with PCa risk in the overall analysis. Moreover, no significant relationship was found in the subgroup analyses by ethnicities, genotyping methods, Hardy-Weinberg equilibrium status, and Gleason score. In the stratified analysis by the source of controls and clinical stages, controls of benign prostatic hyperplasia (BPH) seemed to be in the particular groups in which the association of PCa risk with polymorphism was significant (Bb vs. bb: OR=0.643, 95% CI=0.436-0.949, =0.026; BB/Bb vs. bb: OR=0.627, 95% CI=0.411-0.954, =0.029; B vs. b: OR=0.715, 95% CI=0.530-0.965, =0.029).

Conclusion: Our results suggest that polymorphism is weakly associated with PCa risk, and hence, it cannot be considered as a predictor of the occurrence and development of PCa in clinical practice. Future studies with a larger number of samples are needed to verify our results.