Folic acid supplementation reduces stroke

Objectives:
The AHA/ASA guidelines for primary stroke prevention are almost a decade old. The current recommendation regarding folic acid supplementation is based on only 8 clinical trials and an additional 13 folate trials have been published since then. Therefore, this review article has been conducted.

Does folic acid supplementation reduce stroke risk?

Study design:
This review article included 21 RCTs, totaling 115,559 participants. 
All 21 trials were free of attrition bias and reporting bias and there was no significant publication bias.

Results and conclusions:
The investigators found in the pooled analysis that folic acid supplementation significantly reduced the risk of stroke by 10% [RR = 0.90, 95% CI = 0.83 to 0.98]. 

The investigators found subgroup analyses showed that folic acid efficacy was greater in areas without fortified grain or with partially-fortified grain [RR = 0.83, 95% CI = 0.75 to 0.93; RR = 1.04 in areas with grain fortification, p-interaction = 0.003]. 
In this group, folic acid supplementation was most efficacious in those without a history of stroke or myocardial infarction [RR = 0.77, 95% CI = 0.68 to 0.86; RR = 0.94 for participants with a history of stroke or myocardial infarction, p-interaction = 0.008]. 

The investigators found the efficacy of folic acid remained consistent regardless of baseline folate levels, folic acid dosage, baseline vitamin B12 levels, vitamin B12 dosage, homocysteine reduction, intervention duration and whether folic acid was taken alone or in combination [all p-interaction > 0.05]. 

The investigators concluded folic acid supplementation reduces the risk of stroke. Grain fortification and history of stroke or myocardial infarction may be the most important influences on the efficacy of folic acid for stroke prevention.

Original title: 
Folic acid supplementation for stroke prevention: A systematic review and meta-analysis of 21 randomized clinical trials worldwide by Zhang N, Zhou Z, […], Li J. 

Link:
https://pubmed.ncbi.nlm.nih.gov/38824900/ 

Additional information of El Mondo:
Find more information/studies on folic acid and cardiovascular diseases right here.