Efficacy of folic acid supplementation in stroke prevention: new insight from a meta-analysis
International Journal of Clinical Practice, 06/01/2012
Evidence Based Medicine
Huo Y et al. - The analysis indicated that folic acid supplementation is effective in stroke prevention in populations with no or partial folic acid fortification. In addition, a greater beneficial effect was observed among trials with a lower percent use of statins. The findings underscore the importance of identifying target populations that can particularly benefit from folic acid therapy.Methods
- Relative risk (RR) was used to measure the effect of folic acid supplementation on risk of stroke with a fixed-effects model.
- Overall, folic acid supplementation reduced the risk of stroke by 8% (n = 55,764; RR: 0.92; 95% CI: 0.86-1.00, p = 0.038).
- In the 10 trials with no or partial folic acid fortification (n = 43,426), the risk of stroke was reduced by 11% (0.89; 0.82-0.97, p = 0.010).
- Within these trials, a greater beneficial effect was observed among trials with a lower percent use of statins [≤ 80% (median); 0.77; 0.64-0.92, p = 0.005], and a meta-regression analysis also suggested a positive dose-response relationship between percent use of statins and log-RR for stroke associated with folic acid supplementation (p = 0.013).
- A daily dose of 0.4-0.8mg folic acid appeared to be adequate for stroke prevention in comparison with larger doses.
- In the remaining five trials conducted in populations with folic acid fortification (n = 12,338), folic acid supplementation had no effect on stroke risk (1.03; 0.88-1.21, p = 0.69).