Association between IL-10 rs3024505 and susceptibility to inflammatory bowel disease: A systematic review and meta-analysis

Inflammatory bowel disease (IBD) is a chronic inflammatory disease that affects the small intestine, colon, and rectum. We evaluated associations between the interleukin 10 (IL-10) rs3024505 polymorphism and IBD, ulcerative colitis (UC), and Crohn's disease (CD) by meta-analysis. All peer-reviewed manuscripts concerning the relationship between IL-10_rs3024505 and IBD identified by searing the PubMed, Cochrane Library, EMBASE, and Chinese Medical Database were examined. The association between IL-10_rs3024505 and IBD was evaluated in allele (AG), recessive (RG), dominant (DG), homozygous (HMG), and heterozygous (HTG) genetic models. Associations were also conducted on IBD subtypes, CD and UC, and ethnicity (Non-Europeans and Europeans) subgroups. The meta-analysis included 13 studies, 8552 cases (IBD patients), and 12,830 healthy controls. Subgroup analysis of IBD (UC and CD) revealed heterogeneity in AG, DG, and HTG but no heterogeneity in RG or HMG. Moreover, AG, DG, and HTG did not show publication bias in IBD, CD, or UC, but RG and HMG exhibited publication bias. No heterogeneity and no publication bias were found among the five genetic models by a subgroup analysis of Non-Europeans and European ethnicities. The minor allele(T) of rs3024505 was significantly related to IBD: 1.37 (1.30-1.45) for AG, 2.06 (1.74-2.45) for RG, 1.39 (1.27-1.52) for DG, 2.25 (1.89-2.67) for HMG, and 1.32 (1.23-1.40) for HTG (all P < 0.00001). In the subgroup analysis of ethnicity, there was a significant effect of rs3024505 on IBD in Europeans but not non-Europeans: 1.38 (1.31-1.46) for AG, 2.07 (1.73-2.48) for RG, 1.39 (1.31-1.49) for DG, 2.26 (1.89-2.71) for HMG, and 1.33 (1.24-1.42) for HTG in Europeans (all P < 0.00001). Sensitivity analysis showed no dominant study in Europeans, but one study had a dominant impact in Non-Europeans. In conclusion, IL-10_rs3024505 polymorphism confers susceptibility to CD and UC in Europeans, but its impact should have conducted more studies in Non-Europeans.