Elevated plasma homocysteine concentrations are an independent risk factor for vascular disease. The metabolism of homocysteine is closely related to vitamin B₁₂ and folic acid. The purpose of this study is to evaluate the correlation between homocysteine and vitamin B₁₂ as well as folic acid in patients with coronary artery disease.

Sixteen patients, in whom coronary angiography revealed more than 50% of stenosis at least in one coronary vessel, were enrolled as the patient group, and sixteen hypertensive subjects were selected as the control group. Blood was collected in the peripheral vein to measure the concentrations of homocysteine, vitamin B₁₂, and folate. We evaluated the correlation between homocysteine, vitamin B₁₂ and/or folate in both groups.

Total plasma homocysteine concentrations were higher in the coronary artery disease group than in the control group. There were no significant differences in the folate and vitamin B₁₂ levels between the coronary artery disease group and the control group. In the control group, the concentrations of homocysteine showed negative correlation with both vitamin B₁₂ and folate concentrations, but similar trends were not observed in the coronary artery disease group.