Journal of Inherited Metabolic Disease

, Volume 34, Issue 1, pp 83–91

Homocysteine and vascular disease: review of published results of the homocysteine-lowering trials

  • Robert Clarke
  • Jim Halsey
  • Derrick Bennett
  • Sarah Lewington
Homocysteine and B-Vitamin Metabolism

DOI: 10.1007/s10545-010-9235-y

Cite this article as:
Clarke, R., Halsey, J., Bennett, D. et al. J Inherit Metab Dis (2011) 34: 83. doi:10.1007/s10545-010-9235-y

Abstract

Moderately elevated homocysteine levels have been associated with a higher risk of cardiovascular disease in observational studies, but whether these associations are causal is uncertain. Randomized trials of dietary supplementation with B vitamins were set up to assess whether lowering homocysteine levels could reduce the risk of vascular disease. This review is based on a meta-analysis of published results of eight homocysteine-lowering trials for preventing vascular disease. The eight trials comprised a total of 37,485 individuals and provided comparisons of the effects of B vitamins on 5,074 coronary heart disease (CHD) events, 1,483 stroke events, 2,692 incident cancer events, and 5,128 deaths. Our meta-analysis assessed the effects of lowering homocysteine levels by about 25% for about 5 years. Allocation to B vitamins had no beneficial effects on any cardiovascular events, with hazard ratios (95% confidence intervals) of 1.01 (0.96–1.07) for CHD and 0.96 (0.87–1.07) for stroke. Moreover, allocation to B vitamins had no significant adverse effects on cancer [1.08 (0.99–1.17)], or for death from any cause [1.02 (0.97–1.07)]. Thus, supplementation with B vitamins had no statistically significant effects on the risks of cardiovascular events, total mortality rates, or cancer. A meta-analysis based on individual participant data from all available trials will assess the effects of lowering homocysteine levels on a broader range of outcomes, overall and in all relevant subgroups. However, available evidence does not support the routine use of B vitamins to prevent cardiovascular disease.

Abbreviations

CHD

coronary heart disease

HR

hazard ratio

Copyright information

© SSIEM and Springer 2010

Authors and Affiliations

  • Robert Clarke
    • 1
  • Jim Halsey
    • 1
  • Derrick Bennett
    • 1
  • Sarah Lewington
    • 1
  1. 1.Clinical Trial Service Unit and Epidemiological Studies UnitUniversity of OxfordOxfordUK

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