title: Association of Matrix Metalloproteinase 9 C-1562T Polymorphism with Genetic Susceptibility to Myocardial Infarction: A Meta-Analysis.
abstract: BACKGROUND
  Myocardial infarction (MI) is the major cause of death by disease in the world. Many studies have identified the associations between matrix metalloproteinase 9 (MMP9) C-1562T polymorphisms and MI. However, the results remain inconclusive. To clarify the role of MMP9 C-1562T polymorphism in MI risk, we conducted a systematic review and large-scale meta-analysis.
  
  
  METHODS
  Studies published between January 2005 and March 2014 were obtained from the electronic databases PubMed, Medline, and Embase. The odds ratios (ORs) with 95% CIs were calculated for comparisons of the alleles and genotypes in the overall population and in ethnicity subgroups to measure the strength of genetic associations.
  
  
  RESULTS
  A total of 7 related studies, including 3952 MI cases and 4977 healthy control subjects were included in our meta-analysis. Our results show a statistically significant association between T allele and MI in the overall population (OR = 1.23; 95% CI, 1.02-1.48; P = 0.03). The risk of MI was also significantly higher in patients carrying the T allele (TC + TT genotypes) than in those with the CC genotype (P < 0.05). In stratified analysis by ethnicity, we found the T allele was strongly associated with MI in white populations, whereas in Asian populations there appeared no significant association.
  
  
  CONCLUSIONS
  Our data show that the MMP9 C-1562T polymorphism is a risk factor associated with increased MI susceptibility in the total population and white populations, although no significant association was observed in Asians populations. Further studies with larger sample sizes and assessing gene-gene and gene-environment interactions are required.
authors.affiliation: Department of Cardiovascular Medicine, The Second Affiliated Hospital of Zheng Zhou University, Zhengzhou, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Juan
authors.affiliation: Department of Cardiovascular Medicine, The Second Affiliated Hospital of Zheng Zhou University, Zhengzhou, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Wei-Guo
authors.affiliation: Department of Cardiovascular Medicine, The Second Affiliated Hospital of Zheng Zhou University, Zhengzhou, China.
authors.forename: Song
authors.initials: S
authors.lastname: Heng-Liang
authors.affiliation: Department of Cardiovascular Medicine, The Second Affiliated Hospital of Zheng Zhou University, Zhengzhou, China.
authors.forename: Wan
authors.initials: W
authors.lastname: Da-Guo
keywords: MMP9; meta-analysis; myocardial infarction; polymorphism