MDR1 C3435T polymorphism and inflammatory bowel disease risk: a meta-analysis.

The C3435T polymorphism of the multidrug resistance gene (MDR1) has been implicated in inflammatory bowel disease (IBD) risk, but the reported results are inconsistent. Here we performed a meta-analysis to evaluate the association between C3435T polymorphism and the risk of IBD using all case-control studies published before February 2013 according to PubMed and Web of Science. A total of 13 case-control studies, including 6,757 cases and 4,295 controls, were included. Pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated using fixed- or random-effects model. Overall, no evidence has indicated that the C3435T polymorphism was associated with the susceptibility to IBD (dominant model: OR = 1.05, 95 % CI: 0.96-1.16; CT vs. CC: OR = 1.06, 95 % CI: 0.95-1.17; TT vs. CC: OR = 1.04, 95 % CI: 0.92-1.17; recessive model: OR = 0.99, 95 % CI: 0.90-1.09). Besides, stratified analysis by clinical type also indicated that no significant association between MDR1 C3435T and the risk of Crohn's disease and ulcerative colitis was observed. This meta-analysis indicated that the C3435T polymorphism of MDR1 may not confer susceptibility to IBD.