In summary, we have updated and performed the pooled analyses with 123 studies of 29,697 IHD cases and 31,028 controls for MTHFR 677, and 18 studies of 7158 IHD cases and 5482 controls for MTHFR 1298 polymorphisms, adding the environmental air pollution factor. This evidence concerns the gene MTHFR and myocardial ischemia.