Lack of association of matrix metalloproteinase-3 gene polymorphism with susceptibility to rheumatoid arthritis: a meta-analysis

Background: Epidemiological studies have investigated the association between matrix metalloproteinase-3(MMP-3) gene-1171 5A/6A polymorphism and rheumatoid arthritis (RA), but the results were inconsistent. To evaluate the specific relationship, we performed a meta-analysis to clarify the controversies. Methods: The relevant literatures dated to December 07th 2013 were retrieved from PubMed, EMBASE and the China National knowledge Infrastructure (CNKI) databases. The number of the alleles and genotypes for MMP-3 were obtained. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the association between MMP-3 5A/6A promoter polymorphism and RA. All of the statistical analyses were conducted by STATA11.0 software. Results: A total of 6 case-control studies covering 1451 cases and 1239 controls were included in the final meta-analysis. There was no significant association between MMP-3 5A/6A promoter polymorphism and RA in all genetic models (for 6A versus 5A: OR = 1.19, 95% CI = 0.91-1.56, P = 0.203; 5A/6A versus 5A/5A: OR = 1.31, 95% CI = 0.89-1.92, P = 0.174; 6A/6A versus 5A/5A: OR = 1.78, 95% CI = 0.68-4.61, P = 0.238; the recessive model: OR = 1.48, 95% CI = 0.88-2.47, P = 0.141; and the dominant model: OR = 1.46, 95% CI = 0.71-3.00, P = 0.299). In the subgroup analysis by ethnicity, we obtained the similar results. Conclusions: We systematically investigate the association between MMP-3-1171 5A/6A polymorphism and RA susceptibility; however, the results show a lack of correlation. Considering the small sample size and the selection bias existed in some studies, further studies are needed to confirm the findings.