Correlation between polymorphism of vitamin D receptor TaqI and susceptibility to colorectal cancer: A meta-analysis

The meta-analysis aimed to investigate the correlation between the polymorphism of the vitamin D receptor (VDR) TaqI and susceptibility of colorectal cancer. Studies were extracted from the electronic databases of PubMed and Embase. The balance of heredity was estimated by the Hardy–Weinberg equilibrium test, and heterogeneity was assessed by Cochran Q statistics and I2 test. Four assessed models, namely additive (t vs T), dominant (Tt + tt vs TT), recessive (tt vs Tt + TT), and codominant (Tt vs TT and tt vs TT), were used to evaluate the correlations and the effective results were measured as odds ratio (OR) with 95% confidence interval (CI). A total of 14 studies, including 4632 patients and 5086 controls, were enrolled in this meta-analysis. With no significant heterogeneities observed among the 4 models, the fixed-effect model was used to examine the pooled effect value. There were no significant differences among t vs T (OR = 1.01; 95% CI, 0.94–1.09; P = .70), Tt + tt vs TT (OR = 1.05; 95% CI, 0.96–1.15; P = .32), tt vs Tt + TT (OR = 1.01; 95% CI, 0.87–1.17; P = .92), Tt vs TT (OR = 1.03; 95% CI, 0.93–1.13; P = .62), and tt vs TT (OR = 1.00; 95% CI, 0.85–1.17; P = .98) with respect to increasing CRC frequency. No evidence showed that TaqI polymorphisms were significantly associated with susceptibility to CRC.