Association between ABO blood group and severity of coronary artery disease in unstable angina

ABO blood groups are genetically transmitted through chromosome 9 at locus 9q34. It is supposed that there is a locus on 9p21, which has a role in developing coronary artery disease.
Our study population consisted of 309 patients with unstable angina admitted to the Ziaeian Hospital, Tehran, Iran, who underwent coronary angiography. The association between types of blood group (O and non-O) with the severity of coronary artery disease was investigated.
Compared to the non-O groups, the O group had more severe coronary artery involvement (P = 0.004).
Our study supports recent suggestions on the association between blood group and coronary artery disease. Further studies are needed to evaluate the effect of blood group on atherosclerosis.