Vitamin D receptor (VDR) gene FokI, BsmI, ApaI and TaqI polymorphisms and osteoporosis risk: a meta-analysis

Osteoporosis is a bone disease characterized by low bone density. The prevalence of osteoporosis varies between different populations and ethnic groups. Numerous studies have investigated the relationship between VDR gene polymorphisms and osteoporosis across ethnic populations. Present meta-analysis aims to comprehensively evaluate the influence of common FokI, BsmI, ApaI and TaqI VDR gene polymorphisms and osteoporosis. PubMed, Google Scholar, Springer Link and Elsevier databases were searched for eligible studies and all statistical calculations were performed by Open Meta-Analyst software. Studies investigated BsmI (65 studies; 6,880 case/ 8,049 control), ApaI (31 studies; 3,763 case/ 3,934 control), FokI (18 studies; 1,895 case/ 1,722 control), and TaqI (26 studies; 2,458 case/ 2,895 control) polymorphisms were included in the present meta-analysis. Results of meta-analysis revealed significant association between dominant model of FokI (ORff+Ff vs. FF= 1.19, 95% CI= 1.04-1.36, p= 0.01, I2= 39.36%) in overall analysis and recessive model of Caucasian population of TaqI polymorphism (ORTT+Tt vs. tt= 1.35, 95% CI= 1.11-1.63, p= 0.002, I2= 50.07%). While no such effect is found in any other genetic model in any other gene polymorphisms of the overall analyses or sub-group analyses. In conclusion, we found the FokI polymorphism is associated with osteoporosis in overall analysis, also the TaqI polymorphism is a risk factor for the Caucasian population.