The association between vitamin D receptor gene polymorphisms and the risk of nephrolithiasis: A meta-analysis

Abstract Background Since discovered to affect the expression and function of vitamin D receptor (VDR) protein, the classical VDR gene polymorphisms (Apa-I, BsmI, Fok-I, and Taq-I) were extensively investigated in the case of nephrolithiasis. However, the results remained inconclusive. OBJECTIVES: To perform a meta-analysis concerning the association between the risk of nephrolithiasis and VDR gene polymorphisms (Apa-I, BsmI, Fok-I, and Taq-I). Objectives During January to April, a meta-analysis was conducted. The following information was extracted from each study: author name and year, country of origin, sample size of case and control, and genotype frequency of case and control. A fixed or random effect model was used to determine the correlation and effect estimates. Results Overall, we failed to confirm the association between the risk of nephrolithiasis and both Apa-I and BsmI gene polymorphisms. However, for Fok-I, our results found that FF genotype of Fok-I was associated with increased risk of nephrolithiasis. For Taq-I, T allele and TT genotype were observed having protective effect against nephrolithiasis. While, t allele and tt genotype were susceptible for nephrolithiasis. In sub-group analysis, our findings confirmed that the association between Fok-I and the risk of nephrolithiasis was observed in Asian population. Whereas, the association between Taq-I and the risk of nephrolithiasis was found in Caucasian population. Our effect estimation revealed that Taq-I provided more powerful association with the risk of nephrolithiasis than Fok-I. Conclusions Our meta-analysis reveals that Fok-I and Taq-I of VDR gene polymorphisms are associated with the risk of nephrolithiasis.