Association between MMP-1 g.-1607dupG Polymorphism and Periodontitis Susceptibility: A Meta-Analysis

BACKGROUND Matrix metalloproteinase-1 (MMP-1) plays an important role during the destruction of periodontal tissue. Although multiple studies had focused on the association between MMP-1 g.-1607dupG and periodontitis susceptibility, the results remained inconclusive. The purpose of this meta-analysis was to explore its role in the development of periodontitis. METHODS Retrieved studies from Pubmed, Web of Science, Medline and Google Scholar Search regarding MMP-1 g.-1607dupG and periodontitis susceptibility were included into the final analysis with definite selection and exclusion criteria. Overall and stratified analyses based on disease type, severity, ethnicity and smoking status were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the association between MMP-1 g.-1607dupG and periodontitis susceptibility, while Q test and Egger's test were adopted respectively to assess heterogeneity among studies and publication bias. RESULTS A total of 1580 periodontitis cases and 1386 controls in 11 case-control studies were included in the meta-analysis. The pooled results showed significant association between periodontitis susceptibility and MMP-1 g.-1607dupG polymorphism in homozygote (2G/2G versus 1G/1G, OR = 1.50, 95% CI = 1.02-2.20) and dominant model analysis (2G/2G+2G/1G versus 1G/1G, OR = 1.28, 95% CI = 1.04-1.57). For subgroups by type of periodontitis, increased risk of chronic periodontitis was observed on heterozygote (2G/1G versus 1G/1G, OR = 2.01, 95% CI = 1.58-2.56) and dominant model (OR = 1.27, 95% CI = 1.03-1.57). Furthermore, similar association was also detected in severe chronic periodontitis (2G/2G versus 1G/1G, OR = 2.15, 95% CI = 1.35-3.43; 2G/2G+2G/1G versus 1G/1G, OR = 1.64, 95% CI = 1.12-2.39; 2G/2G versus 2G/1G+1G/1G, OR = 1.86, 95% CI = 1.31-2.64). CONCLUSIONS Our meta-analysis demonstrated that MMP-1 g.-1607dupG polymorphism was associated with chronic periodontitis, especially the severity of the disease condition.