Homocysteine, vitamins, and coronary artery disease - Comprehensive reviewof the literature

OBJECTIVE To summarize results of clinical trials investigating the role of homocysteine (tHcy) as a risk factor for coronary artery disease (CAD) and the role of vitamin therapy (folic acid and vitamins B-6 and B-12) in prim ary and secondary prevention of CAD. QUALITY OF EVIDENCE MEDLINE was searched from January 1976 to January 1999 to locate cross-sectional, retrospective and prospective cohort studies and meta-analyses on CAD using the MeSH words homocysteine, folic acid, vitami ns B-6 and B-12, and coronary artery or heart disease. MAIN MESSAGE Elevated tHcy levels are prevalent; most retrospective and cro ss-sectional studies show an association with increased risk of CAD. Result s from recent prospective studies are less consistent. Folic acid, alone or with vitamins B-6 and B-12, reduces tHcy concentrations in the blood. Resu lts from ongoing randomized controlled trials could determine the effect of vitamins B-6 and B-12 and folic acid supplementation on CAD-related morbid ity and mortality and could indicate whether routine supplementation with t hese vitamins should be advocated. Before mass screening for tHcy can be do ne, the tHcy assay must be standardized. CONCLUSION The role of homocysteine and vitamins B-6 and B-12 in managing C AD is unclear. Routine screening is not recommended.