Objective: To determine whether macrophage migration inhibitory factor (MIF) gene polymorphism is associated with the risk of inflammatory bowel disease (IBD).

Methods: System review and meta-analysis. Methods: MEDLINE, EMBASE, Web of Science databases, Cochrane Library and the Chinese Biomedical Literature database (CBM) were searched for the case-control trails for MIF and IBD. All the studies included in this manuscript met the inclusion and exclusion criteria. An OR analysis using a 95% CI was employed to assess the association of the MIF-173 G/C polymorphism with IBD susceptibility.

Results: There was a significant association between the MIF-173 G/C gene polymorphism and IBD in the total population under the recessive model (CC vs GC+GG; OR=1.75, CI 1.04 to 2.95, p=0.04 for heterogeneity) and the codominant model (CC vs GG; OR=1.74, CI 1.02 to 2.97, p=0.04 for heterogeneity). In the stratified analysis by ethnicity, significantly increased risks were observed for Asians using the recessive (OR=1.75, CI 1.04 to 2.95, p=0.04 for heterogeneity) and codominant models (OR=1.74, CI 1.02 to 2.97, p=0.04 for heterogeneity). Within the subgroups of UC and CD, significant differences were observed regarding UC using the recessive (OR=1.60, CI 1.09 to 2.35, p=0.02 for heterogeneity) and codominant models (OR=1.64, CI 1.12 to 2.41, p=0.01 for heterogeneity). In the stratified analysis by ethnicity for UC, significant differences were observed regarding CC in Asians vs GC+GG (OR=1.73, CI 1.02 to 2.94, p=0.04 for heterogeneity).

Conclusions: The meta-analysis suggested that the MIF-173 G/C polymorphism contributed to the susceptibility of IBD. When considering the subgroups of ethnicity and UC and CD, the results suggested that the polymorphism is more significant for UC in Asians.