Homocysteine has been noted to be consistently higher in patients with occlusive vascular disease than in controls, and this difference is also seen prior to the onset of disease. \u00a0Although previous large-scale randomised trials have failed to show any benefit from lowering homocysteine levels through the use of folic acid based supplements, the reasons for this have remained unclear, and subsequent subgroup analysis has suggested a protective effect on stroke. \u00a0The SEARCH (Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine) trial examined the affects of lowering homocysteine levels using 2mg of folic acid and 1mg vitamin B12 daily.<\/p>\n
The study followed 12064 survivors of myocardial infarction who were assigned to either B12\/folate or placebo. \u00a0The main outcome measure was the first major vacular event, defined as a major coronary event (coronary death, myocardial infarction, or revascularisation), stroke, or noncoronary revascularisation.<\/p>\n
Although allocation to the study vitamins reduced homocysteine levels by a mean of 3.8 umol\/L (28%), over 6.7 years of follow-up no significant difference was noted in the incidence of major vascular events between the treatment and control groups (25.5% vs 24.8%; p=.28). \u00a0Furthermore there was no significant difference in the numbers of deaths attributed to vascular causes (9.6% vs 9.3%) or nonvascular causes (6.7% vs 6.5%). \u00a0No adverse effect on cancer incidence was noted.<\/p>\n
Conclusion:
\nDespite significant reductions in blood homocysteine levels, B12\/folic acid supplementation had no beneficial effects on vascular outcomes in patients who had previously sustained a myocardial infarction.
\n\u2022 SEARCH Collaborative Group. \u00a0Effects of Homocysteine-Lowering With Folic Acid Plus Vitamin B12 vs Placebo on Mortality and Major Morbidityin Myocardial Infarction Survivors. \u00a0JAMA 2010;303(24):2486-2494.<\/p>\n","protected":false},"excerpt":{"rendered":"
Homocysteine has been noted to be consistently higher in patients with occlusive vascular disease than in controls, and this difference is also seen prior to the onset of disease. \u00a0Although previous large-scale randomised trials have failed to show any benefit from lowering homocysteine levels through the use of folic acid based supplements, the reasons for […]<\/p>\n