Background: An elevated plasma homocysteine level is an established risk factor for cardiovascular disease. Vitamin B12 plays a key role in homocysteine metabolism and could be the main factor in causing cardiovascular disease as well. Objectives: The aim of this study was to assess whether vitamin B12 deficiency or hyperhomocysteinaemia is associated with recurrent cardiovascular events. Methods: Overall, 211 patients discharged alive from our Coronary Care Unit were recruited from February till May 1998. Serum vitamin B12 and plasma homocysteine levels were measured in fasting blood samples. Patient characteristics, medical information and cardiovascular risk factors were assessed from medical files. Patients were followed for 5 years and the prevalence of cardiovascular mortality and morbidity was collected. Results: In the follow-up period of 810 person-years, 48 (21%) of the patients experienced a nonfatal recurrent cardiovascular event and another 14 (7%) died of a cardiovascular cause. Among those with ischaemic heart disease at discharge, no difference in survival was found between the patients with a low (<250 pmol/l) or a high vitamin B12 level (p = 0.21). In patients with hyperhomocysteinaemia (>16 µmol/l), an increased risk of a recurrent cardio vascular event (p = 0.05) in comparison to those with normal plasma homocysteine levels was proven (adjusted hazard ratio of 2.22 (95% CI: 1.40–3.04). Conclusions: In conclusion, high plasma homocysteine concentration, but not a low serum vitamin B12 concentration, increases the risk of cardiovascular morbidity and mortality in patients with ischaemic heart disease.

Keywords:
Homocysteine, Vitamin B12, Ischaemic heart disease, Long-term effects
1.
Taylor BV, Oudit GY, Evans M: Homocysteine, vitamins and coronary artery disease; comprehensive review of the literature. Can Fam Physician 2000;46:2236–2245.
2.
Wald DS, Law M, Morris JK: Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis. BMJ 2002;325:1202–1208.
3.
Medrano MJ, Sierra MJ, Almazan J, Olalla MT, Lopez-Abente G: The association of dietary folate, B6, and B12 with cardiovascular mortality in Spain: an ecological analysis. Am J Public Health 2000;90:1636–1638.
4.
Hung J, Beilby JP, Knuiman MW, Divitini M: Folate and vitamin B-12 and risk of fatal cardiovascular disease: cohort study from Busselton, Western Australia. BMJ 2003;326:131–136.
5.
Clarke R, Collins R, Lewington S, Donald A, Alfthan G, Tuomilehto J, et al: Homocysteine as risk of heart disease and stroke; a meta-analysis. JAMA 2002;288:2015–2023.
6.
De Bree A, Verschuren WM, Blom HJ, Nadeau M, Trijbels FJ, Kromhout D: Coronary heart disease mortality, plasma homocysteine, and B-vitamins: a prospective study. Atherosclerosis 2003;166:369–377.
7.
Lim HS, Heo YR: Plasma total homocysteine, folate, and vitamin B12 status in Korean adults. J Nutr Sci Vitaminol (Tokyo) 2002;48:290–297.
8.
Suliman ME, Qureshi AR, Barany P, Stenvinkel P, Filho JC, Anderstam B, Heimburger O, Lindholm B, Bergstrom J: Hyperhomocysteinemia, nutritional status, and cardio vascular disease in hemodialysis patients. Kidney Int 2000;57:1727–1735.
9.
Bostom AG, Shemin D, Verhoef P, Nadeau MR, Jacques PF, Selhub J, Dworkin L, Rosenberg IH: Elevated fasting total plasma homocysteine levels and cardiovascular disease outcomes in maintenance dialysis patients: a prospective study. Arterioscler Thromb Vasc Biol 1997;17:2554–2558.
10.
Toole JF, Malinow MR, Chambless LE, Spence JD, Pettigrew LC, Howard VJ, Sides EG, Wang C-H, Stampfer M: Lowering homocysteine in patients with ischemic stroke to prevent recurrent stroke, myocardial infarction, and death. The Vitamin Intervention for Stroke Prevention (VISP) randomized controlled trial. JAMA 2004;291:565–575.
11.
The Heart Outcomes Prevention Evaluation (HOPE) 2 Investigators. Homocysteine lowering with folic acid and B vitamins in vascular disease. N Engl J Med 2006;354:1567–1577.
12.
Bønaa KH, Njølstad I, Ueland PM, Schirmer H, Tverdal A, Steigen T, Wang H, Nordrehaug JE, Arnesen E, Rasmussen K, for the NORVIT Trial Investigators: Homocysteine lowering and cardiovascular events after acute myocardial infarction. N Engl J Med 2006;354:1578–1588.
© 2007 S. Karger AG, Basel
2006
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.