降低homocystein無法降低CVD，第八個實驗證明
Vit B12 + folate 降低homocystein但對CVD無效
Yet Another Study of Lowering Homocysteine to Prevent Vascular Disease
An eighth randomized trial showed no benefit.
Higher blood levels of homocysteine clearly are associated with higher risk for cardiovascular (CV) disease, but seven major randomized trials have shown no benefit for lowering homocysteine levels with folic acid. Despite the accumulating evidence, these studies have been criticized as being too small, too short, or insufficiently controlled to show a true benefit. U.K. investigators randomized about 12,000 high-risk patients (survivors of myocardial infarction [MI]; mean age, 64) to daily folic acid (2 mg) plus vitamin B12 (1 mg) or placebo. Patients with major chronic diseases or cancer or unexpectedly low cholesterol levels were excluded.
During a mean 7 years of follow-up, folate and vitamin B12 levels rose two- to threefold and homocysteine levels dropped by about 30% in the active-treatment group. Major vascular events (nonfatal and fatal MIs, nonfatal and fatal strokes, and coronary or noncoronary revascularizations) occurred in about 25% of participants; overall mortality was about 16%; and incident cancer (excluding nonmelanoma skin cancer) was about 11%. No difference was noted between the active-treatment and placebo groups in any primary outcome nor were differences found in several secondary vascular outcomes.
Comment: These results, and those of the seven prior major trials, should end what seems to be an unjustified persistence by many clinicians to recommend folate supplementation to prevent CV disease. Clinical efforts should focus on modification of CV risk factors, for which evidence supports improved outcomes.
— Thomas L. Schwenk, MD
Published in Journal Watch General Medicine July 8, 2010
Citation(s):
Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH) Collaborative Group. Effects of homocysteine-lowering with folic acid plus vitamin B12 vs placebo on mortality and major morbidity in myocardial infarction survivors: A randomized trial. JAMA 2010 Jun 23/30; 303:2486. (http://dx.doi.org/10.1001/jama.2010.840)
* Original article (Subscription may be required)
* Medline abstract (Free)
Yet Another Study of Lowering Homocysteine to Prevent Vascular Disease
An eighth randomized trial showed no benefit.
Higher blood levels of homocysteine clearly are associated with higher risk for cardiovascular (CV) disease, but seven major randomized trials have shown no benefit for lowering homocysteine levels with folic acid. Despite the accumulating evidence, these studies have been criticized as being too small, too short, or insufficiently controlled to show a true benefit. U.K. investigators randomized about 12,000 high-risk patients (survivors of myocardial infarction [MI]; mean age, 64) to daily folic acid (2 mg) plus vitamin B12 (1 mg) or placebo. Patients with major chronic diseases or cancer or unexpectedly low cholesterol levels were excluded.
During a mean 7 years of follow-up, folate and vitamin B12 levels rose two- to threefold and homocysteine levels dropped by about 30% in the active-treatment group. Major vascular events (nonfatal and fatal MIs, nonfatal and fatal strokes, and coronary or noncoronary revascularizations) occurred in about 25% of participants; overall mortality was about 16%; and incident cancer (excluding nonmelanoma skin cancer) was about 11%. No difference was noted between the active-treatment and placebo groups in any primary outcome nor were differences found in several secondary vascular outcomes.
Comment: These results, and those of the seven prior major trials, should end what seems to be an unjustified persistence by many clinicians to recommend folate supplementation to prevent CV disease. Clinical efforts should focus on modification of CV risk factors, for which evidence supports improved outcomes.
— Thomas L. Schwenk, MD
Published in Journal Watch General Medicine July 8, 2010
Citation(s):
Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH) Collaborative Group. Effects of homocysteine-lowering with folic acid plus vitamin B12 vs placebo on mortality and major morbidity in myocardial infarction survivors: A randomized trial. JAMA 2010 Jun 23/30; 303:2486. (http://dx.doi.org/10.1001/jama.2010.840)
* Original article (Subscription may be required)
* Medline abstract (Free)
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