title: Efficacy of folic acid supplementation in stroke prevention: a meta-analysis.
abstract: BACKGROUND
  The efficacy of treatments that lower homocysteine concentrations in reducing the risk of cardiovascular disease remains controversial. Our aim was to do a meta-analysis of relevant randomised trials to assess the efficacy of folic acid supplementation in the prevention of stroke.
  
  
  METHODS
  We 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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  Our findings indicate that folic acid supplementation can effectively reduce the risk of stroke in primary prevention.
authors.affiliation: Mary Ann and J Milburn Smith Child Health Research Program, Children's Memorial Hospital and Children's Memorial Research Center, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. Electronic address: xbwang@childrensmemorial.org.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute for Biomedicine, Anhui Medical University, Hefei, China.
authors.forename: Xianhui
authors.initials: X
authors.lastname: Qin
authors.affiliation: Division of Epidemiology and Biostatistics, University of Illinois at Chicago School of Public Health, Chicago, IL, USA.
authors.forename: Hakan
authors.initials: H
authors.lastname: Demirtas
authors.affiliation: Department of Cardiology, First Hospital of Peking University, Beijing, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Li
authors.affiliation: Institute for Biomedicine, Anhui Medical University, Hefei, China.
authors.forename: Guangyun
authors.initials: G
authors.lastname: Mao
authors.affiliation: Department of Cardiology, First Hospital of Peking University, Beijing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huo
authors.affiliation: Department of Cardiology, People's Hospital of Peking University, Beijing, China.
authors.forename: Ningling
authors.initials: N
authors.lastname: Sun
authors.affiliation: Division of Hypertension, Fu-Wai Hospital, Beijing, China; Cardiovascular Institute, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Lisheng
authors.initials: L
authors.lastname: Liu
authors.affiliation: Division of Epidemiology and Biostatistics, University of Illinois at Chicago School of Public Health, Chicago, IL, USA.
authors.forename: Xiping
authors.initials: X
authors.lastname: Xu
mesh_terms: D000368:Aged; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D020521:Stroke / Q000517:prevention & control*; D014803:Vitamin B Complex / Q000627:therapeutic use*
chemical_list: D006710:Homocysteine; D014803:Vitamin B Complex; D005492:Folic Acid