Indian J Med Res 119, January 2004, pp 33-37 Hyperhomocysteinaemia & folic acid supplementation in patients with high risk of coronary artery disease Hangyuan Guo † , Jong-Dae Lee*, Takanori Ueda*, Jianfeng Cheng, Jiang Shan & Jian’an Wang Department of Cardiology, Sir Run Run Shaw Hospital, Medical College, Zhejiang University, Hangzhou 310016, China & *First Department of Internal Medicine, Medical College, Fukui University, Fukui 910-1193, Japan Received April 10, 2003 Background & objectives: Many traditional independent risk factors such as diabetes mellitus, hypertension, hypercholesterolaemia, smoking, male sex, old age, etc., contribute to the development of coronary artery disease (CAD). Hyperhomocysteinaemia is an independent risk factor of CAD but the role of plasma homocysteine (Hcy) in high risk patients ( ≥ 3 risk factors) is not known. We investigated the role of plasma Hcy, folic acid, vitamin B 12 in patients with high risk (≥ 3 risk factors) of CAD and effects of supplementation of folic acid in the patients with hyperhomocysteinaemia. Methods : The plasma Hcy levels in 152 patients with ≥ 3 risk factors of CAD and 136 patients with 1-2 risk factors and 48 individuals with no risk factors were measured using high performance liquid chromatography (HPLC) with fluorescence detection. Plasma folic acid and vitamin B 12 levels were also measured in these patients with immunoassays. The patients with hyperhomocysteinaemia were treated with 5 mg of folic acid for 8 wk, and plasma levels of Hcy were measured after treatment. Results: The plasma Hcy level was significantly higher in the patients with ≥ 3 risk factors of CAD than in those with 1-2 risk factors and controls. The plasma levels of folic acid and vitamin B 12 were significantly lower in the patients with ≥ 3 risk factors of CAD compared to those with 1-2 risk factors and controls. The Hcy levels in the patients with ≥ 3 risk factors of CAD significantly reduced by 33.5 per cent after 8 wk folic acid administration. Interpretation & conclusion: Plasma Hcy level was elevated significantly in patients with ≥ 3 risk factors of CAD. Hyperhomocysteinaemia appears to play an important role in the pathogenesis of CAD. Folic acid supplementation may be useful in reducing plasma Hcy level in high risk patients with hyperhomocysteinaemia. Key words Coronary artery disease - folic acid - homocysteine - risk factor - vitamin B 12 Homocysteinuria was first reported by Carson & Neill 1 . McCully 2 found the relationship between homocysteine and vascular disease. More recently mild to moderate elevation of plasma homocysteine concentration (Hcy) has been recognized as an important risk factor for the development of atherosclerotic vascular disease 3 . The relationship between elevation of plasma homocysteine levels and risk of developing CAD is not well studied. It is known that many traditional independent risk factors such as diabetes mellitus, hypertension, hypercholesterolaemia, smoking, male sex and old age, etc. contribute to the development of atherosclerotic vascular disease 3 . The present study was undertaken to study the plasma levels of homocysteine in patients with high risk ( ≥3 risk factors) of CAD, and to observe the effects of folic acid supplementation in these patients with hyperhomocysteinaemia. 33 † Present address : First Department of Internal Medicine, Medical College, Fukui University, Fukui 910-1193, Japan