The angiotensinogen gene M235T polymorphism and acute myocardial infarction risk: a meta-analysis of 22 studies.

Angiotensinogen, one of the most important proteins in the renin-angiotensin system, plays a key role in the progress of coronary heart disease and myocardial infarction (MI). Many studies have investigated the association between angiotensinogen gene M235T polymorphism and MI risk, but the results were inconsistent. We performed a meta-analysis of 22 studies on M235T polymorphism and MI risk published before November 2012. This meta-analysis included a total of 4,606 MI cases and 4,918 controls. Overall, the per-allele odds ratio (OR) of the 235T variant for total MI risk was 1.04 (95 % CI 0.92-1.17). When a recessive model was evaluated, the OR was 1.06 (95 % CI 0.96-1.17) and under a dominant model, the OR was 0.96 (95 % CI 0.82-1.11). Under pairwise comparisons, non-significant associations were found between M235T polymorphism and MI risk (MT vs. MM, OR, 0.96, 95 % CI 0.87-1.06; TT vs. MM, OR, 1.03, 95 % CI 0.83-1.28). Subgroup analyses in the different ethnic groups and different control sources were performed and no significant association was found also. Based on the available evidence, no association between M235T polymorphism and MI risk was observed, even in the sub-analysis concerning different races and control sources. The direction of further research should focus not only on the simple relationship of M235T polymorphism and MI risk, but also on gene-gene and gene-environment interaction.