Homocysteine-lowering interventions for preventing cardiovascular events

Area of Science:

• Cardiovascular medicine
• Nutritional science
• Clinical research methodology

Background:

• Cardiovascular disease (CVD) is a major global cause of mortality.
• Elevated homocysteine levels are a potential risk factor for CVD.
• This review examines vitamin B supplements for lowering homocysteine and preventing cardiovascular events.

Purpose of the Study:

• To assess the efficacy of homocysteine-lowering interventions (vitamin B supplements) in preventing cardiovascular events and all-cause mortality.
• To evaluate the safety of these interventions in patients with and without pre-existing CVD.

Main Methods:

• Included 15 randomized controlled trials (71,422 participants) comparing homocysteine-lowering interventions with placebo.
• Primary outcomes were myocardial infarction and stroke; secondary outcomes included all-cause mortality and adverse events.
• Data were analyzed using risk ratios and random-effects models, with high-quality evidence considered.

Main Results:

• No significant differences were observed in myocardial infarction, all-cause mortality, or serious adverse events between intervention and placebo groups.
• Homocysteine-lowering interventions showed a statistically significant reduction in stroke events (RR 0.90, 95% CI 0.82 to 0.99).
• Effects of high-dose interventions on stroke were uncertain due to very low-quality evidence.

Conclusions:

• Vitamin B supplements (B6, B9, B12) for homocysteine lowering do not impact myocardial infarction, all-cause mortality, or adverse events compared to placebo.
• A small benefit was observed for stroke prevention with these vitamin supplements.
• Further large, co-operative trials are needed to investigate high-dose interventions and combined therapies with antihypertensives.