Polymorphisms of matrix metalloproteinases in myocardial infarction: a meta-analysis

CONTEXT: The literature provides no clear answer as to whether matrix metalloproteinases (MMPs) polymorphisms increases risk of myocardial infarction (MI). OBJECTIVE: Our purpose was to help clarify the inconsistent findings of MMPs polymorphisms and MI susceptibility and identify which MMP polymorphism might play an active role in the occurrence of MI. DATA SOURCES: Articles were identified by a Medline search and citation tracking. STUDY SELECTION: Eligible articles were case-control studies of MMPs polymorphisms and MI which met our prespecified criteria. DATA EXTRACTION: Data were independently extracted by two authors according to a predefined protocol. Incongruities were settled by consensus decision. RESULTS AND CONCLUSIONS: 18 potentially eligible articles were identified. In a combined analysis, the 5A allele of the MMP-3 5A/6A polymorphism was associated with MI (OR 1.21, 95% CI 1.01 to 1.46, p=0.04), suggesting its role in plaque rupture. In the subgroup analysis by ethnicity, significantly increased risk was found among East Asians (OR 1.39, 95% CI 1.01 to 1.91, p=0.04), whereas no significant association was detected in Caucasian populations. In addition, there were significant associations of the MMP-9 -1562C→T polymorphism with MI (OR 1.14, 95% CI 1.02 to 1.27, p=0.02), whereas the heterogeneity of the studies showed no significance (I(2)=13.7%, p=0.32). This meta-analysis demonstrated that the MMP-3 5A/6A and MMP-9 -1562 C→T polymorphisms are risk factors associated with increased MI susceptibility, but these associations vary in different ethnic populations.