The results of the pooled odds ratio (OR) for the MTHFR 677 polymorphisms presented greater ratios, as compared to the RRs, for IHD risk (TT: OR = 1.28, p < 0.0001; CT: OR = 1.08, p = 0.0012, and TT plus CT: OR = 1.22, p < 0.0001), with the T allele having a 17% greater odds of developing IHD (OR = 1.17, p < 0.0001) versus the CC wildtype (OR = 0.82, p < 00001), which presented a lesser odds as compared to RR against IHD, with holders of the C allele having a 15% lesser odds of developing IHD (OR = 0.85, p < 0.0001). Here, MTHFR is linked to myocardial ischemia.