[Elevated levels of homocysteine in plasma as a risk factor for coronary artery disease]

This study was performed to assess the significance of association between coronary artery disease (CAD) and circulating homocysteine concentrations. 100 consecutive CAD patients (78 men and 22 women, aged 31 to 79 years) qualified for PTCA were investigated. At the time of PTCA, the risk factors for CAD and plasma for homocysteine and vitamins were obtained. The controls were without clinical evidence of coronary artery disease and hypertension (90 men and 30 women aged 32 to 81 years). Homocysteine was assayed using ELISA test. Red cell folate and plasma vitamin B12 were assayed by immunofluoroscency (Delphia test). Homocysteine concentrations were higher in patients than in controls (13.61 +/- 4.5 vs 10.99 +/- 4.49 mumol/L, p < 0.001, adjusted for age). Male patients had nonsignificantly higher homocysteine levels than females (13.94 +/- 5.21 vs 11.46 +/- 5.16 mumol/L, p = 0.05, adjusted for age). Elevated homocysteine level--defined as one in the top fifth of the control distribution > or = 12.83 mumol/L--was seen in 46% of the patients compared with 20% of the control group (p = 0.001). The odds ratio (OR) for CAD in persons with elevated homocysteine level was 3.1 (95% Cl 1.6-5.8, p < 0.001, adjusted for age). The OR for CAD of 5 mumol/L increment in homocysteine level was 2.1 (95% Cl 1.4-3.1 p < 0.001, adjusted for age). After adjustment for conventional risk factors (age, smoking, hypertension, family history of CAD, hyperlipidemia), elevated homocysteine level remained independent risk factor for CAD (OR 2.88, 95% Cl 1.1-7.8, p < 0.05). We observed inverse correlation between homocysteine and folate level (r = -0.32, p = 0.005) and between homocysteine and vitamin B12 concentrations (r = -0.24, p = 0.03), especially in men. Patients with elevated homocysteine level had lower levels of folate (629.6 +/- 241.2 nmol/L vs 735.1 +/- 252.4 nmol/L, p < 0.05), and vitamin B12 (213.6 +/- 64.4 pmol/L vs 246.6 +/- 62.3 pmol/L, p < 0.05) than patients with normal level of homocysteine. Elevated plasma homocysteine level is a strong risk factor for coronary artery disease. A 5 mumol/L increment in total homocysteine level may be associated with twofold increase of risk for the disease.