Does lowering homocysteine levels have a cardiovascular benefit?

January 01, 0001

Does lowering homocysteine levels have a cardiovascular benefit?

Elevated homocysteine levels have been linked with cardiovascular disease. These British researchers tested whether lowering blood homocysteine levels would have an effect on cardiovascular risk in patients with cardiovascular disease. They performed a double-blind randomized placebo- controlled trial of 12,064 patients who had myocardial infarction. Patients were randomized to either 2 mg of folic acid and 1mg of vitamin B12 or to placebo.

The researchers found: "Allocation to the study vitamins reduced homocysteine by a mean of 3.8 µmol/L (28%). During 6.7 years of follow-up, major vascular events occurred in 1537 of 6033 participants (25.5%) allocated folic acid plus vitamin B12 vs 1493 of 6031 participants (24.8%) allocated placebo (RR, 1.04). There were no apparent effects on major coronary events (vitamins, 1229 {20.4%}, vs placebo, 1185 {19.6%}, RR, 1.05), stroke (vitamins, 269 {4.5%}, vs placebo 265 {4.4%}, RR, 1.02), or noncoronary revascularizations (vitamins, 178 {3.0%}, vs placebo, 152 {2.5%}, RR, 1.18). Nor were there significant differences in the numbers of deaths attributed to vascular causes (vitamins, 578 {9.6%}, vs placebo, 559 {9.3%}) or nonvascular causes (vitamins, 405 {6.7%}, vs placebo, 392 {6.5%}) or in the incidence of any cancer (vitamins, 678 {11.2%}, vs placebo, 639 {10.6%})."

The authors concluded: "Substantial long-term reductions in blood homocysteine levels with folic acid and vitamin B12 supplementation did not have beneficial effects on vascular outcomes but were also not associated with adverse effects on cancer incidence."

This randomized controlled trial found no evidence that lowering homocysteine levels in patients following myocardial infarction had any benefit on subsequent cardiovascular risk.

For the full abstract, click here.

JAMA 303(24):2486-2494, 23 June 2010
© 2010 the American Medical Association
Effects of Homocysteine-Lowering With Folic Acid Plus Vitamin B12 vs Placebo on Mortality and Major Morbidity in Myocardial Infarction Survivors- A Randomized Trial. Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH) Collaborative Group.

Category: K. Circulatory. Keywords: homocysteine, folate, vitamin B12, cardiovascular risk, myocardial infarction, randomized controlled trial, journal watch.
Synopsis edited by Dr Paul Schaefer, Toledo, Ohio. Posted on Global Family Doctor 13 July 2010

Pearls are an independent product of the Cochrane primary care group and are meant for educational use and not to guide clinical care.