BsmI, TaqI, ApaI, and FokI polymorphisms in the vitamin D receptor gene and periodontitis: a meta-analysis of 15 studies including 1338 cases and 1302 controls

P>Aim A meta-analysis was conducted in order to investigate the potential association of vitamin D receptor (VDR) gene polymorphisms with susceptibility to aggressive and chronic periodontal disease. Material and Methods A database search yielded a total of 15 studies involving 1338 cases and 1302 controls. Four polymorphisms were included in the meta-analysis: VDR TaqI (rs731236), VDR BsmI (rs1544410), VDR FokI (rs2228570), and VDR ApaI (rs7975232). Odds ratios (ORs) along with their 95% confidence intervals (CIs) were computed to compare the distribution of alleles and genotypes between cases and controls. Results and Conclusions The combined results based on all studies showed that (1) chronic periodontitis cases had a significantly lower frequency of bb genotype of BsmI [OR=0.63, 95% CI=0.42, 0.94; p=0.02] in Asians; (2) chronic periodontitis cases had a significantly higher frequency of AA genotype of ApaI (OR=2.20, 95% CI=1.39, 3.48; p < 0.001) in Asians; (3) chronic periodontitis cases had a weak significantly higher frequency of TT genotype of TaqI (OR=1.86, 95% CI=1.002, 3.46; p=0.049) in Asians. After Bonferroni's correction, we found that in Asians chronic periodontitis cases still had a significantly higher frequency of AA genotype of ApaI. No significant difference was found in any genotype of FokI. No association was found for all the VDR gene polymorphisms examined as far as the aggressive form of the disease is concerned. Future studies need to focus on the possible biological consequences and mechanisms of the VDR genetic variants. The current findings confirm that VDR gene is a candidate gene for periodontitis.