Clinical Health Updates

Folate prevents stroke

Clinical Question:
Does folic acid supplementation prevent stroke?

Bottom Line:
If these authors identified all the relevant clinical trials, folic acid supplementation for at least 36 months prevents stroke, especially in patients with no prior history of stroke.

Wang X, Qin X, Demirtas H, et al. Efficacy of folic acid supplementation in stroke prevention: a meta-analysis. Lancet 2007;369:1876-1882.

Study Design:
Meta-analysis (randomized controlled trials)

Up to now the efficacy of treatments that lower homocysteine concentrations in reducing the risk of cardiovascular disease remains controversial. So the investigators did a meta-analysis of relevant randomised trials to assess the efficacy of folic acid supplementation in the prevention of stroke. They collected data from eight randomised trials of folic acid that had stroke reported as one of the endpoints. Relative risk (RR) was used as a measure of the effect of folic acid supplementation on the risk of stroke with a random effect model. The analysis was further stratified by factors that could affect the treatment effects. Folic acid supplementation significantly reduced the risk of stroke by 18% (RR 0.82, 95% CI 0.68-1.00; p=0.045). In the stratified analyses, a greater beneficial effect was seen in those trials with a treatment duration of more than 36 months (0.71, 0.57-0.87; p=0.001), a decrease in the concentration of homocysteine of more than 20% (0.77, 0.63-0.94; p=0.012), no fortification or partly fortified grain (0.75, 0.62-0.91; p=0.003), and no history of stroke (0.75, 0.62-0.90; p=0.002). In the corresponding comparison groups, the estimated RRs were attenuated and insignificant.