Meta-Analysis of Apolipoprotein E Gene Polymorphism and Susceptibility of Myocardial Infarction

A number of case-control studies have been conducted to clarify the association between ApoE polymorphisms and myocardial infarction (MI); however, the results are inconsistent. This meta-analysis was performed to clarify this issue using all the available evidence. Searching in PubMed retrieved all eligible articles. A total of 33 studies were included in this meta-analysis, including 18752 MI cases and 18963 controls. The pooled analysis based on all included studies showed that the MI patients had a decreased frequency of the epsilon 2 allele (OR = 0.78, 95% CI = 0.70-0.87) and an increased frequency of the epsilon 4 allele (OR = 1.15, 95% CI = 1.10-1.20); The results also showed a decreased susceptibility of MI in the epsilon 2 epsilon 3 vs. epsilon 3 epsilon 3 analysis (OR = 0.79, 95% CI = 0.68-0.90) and in the epsilon 2 vs. epsilon 3 analysis (OR = 0.78, 95% CI = 0.69-0.89), an increased susceptibility of MI in the epsilon 3 epsilon 4 vs. epsilon 3 epsilon 3 analysis (OR = 1.26, 95% CI = 1.12-1.41), in the epsilon 4 vs. epsilon 3 analysis (OR = 1.22, 95% CI = 1.12-1.32) and in the epsilon 4 epsilon 4 vs. epsilon 3 epsilon 3 analysis (OR = 1.59, 95% CI = 1.15-2.19). However, there were no significant associations among polymorphisms and MI for the following genetic models: frequency of the epsilon 3 allele (OR = 0.99, 95% CI = 0.96-1.02); epsilon 2 epsilon 2 vs. epsilon 3 epsilon 3 analysis (OR = 0.73, 95% CI = 0.40-1.32); or epsilon 2 epsilon 4 vs. epsilon 3 epsilon 3 analysis (OR = 1.10, 95% CI = 0.99-1.21). Our results suggested that the epsilon 4 allele of ApoE is a risk factor for the development of MI and the epsilon 2 allele of ApoE is a protective factor in the development of MI.