title: Effect of folic acid, with or without other B vitamins, on cognitive decline: meta-analysis of randomized trials.
abstract: OBJECTIVE
  We aimed to quantify the effect of folic acid supplementation on the prevention of cognitive decline.
  
  
  METHODS
  We conducted a meta-analysis of 9 placebo-controlled randomized trials (2835 participants, median duration 6 months) of folic acid, with or without other B vitamins, on cognitive function. Standardized mean differences in cognitive function test scores were calculated between folic acid and placebo-treated groups.
  
  
  RESULTS
  The standardized mean difference in cognitive function test scores was 0.01 (95% confidence interval [95% CI], -0.08 to 0.10), or an increase of 1% (95% CI, -8% to 10%) of 1 standard deviation. The results were similar within each of the 4 categories of cognitive function (memory, speed, language, and executive function); standardized mean differences were 0.01 (95% CI, -0.08 to 0.09), -0.01 (95% CI, -0.10 to 0.13), -0.05 (95% CI, -0.15 to 0.04), and 0.03 (95% CI, -0.13 to 0.19), respectively.
  
  
  CONCLUSIONS
  Randomized trials show no effect of folic acid, with or without other B vitamins, on cognitive function within 3 years of the start of treatment. Trials of longer duration, recording the incidence of dementia, as well as cognitive decline, are needed.
authors.affiliation: Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine, Queen Mary University of London, London, UK. d.s.wald@qmul.ac.uk
authors.forename: David S
authors.initials: DS
authors.lastname: Wald
authors.forename: Anuradhani
authors.initials: A
authors.lastname: Kasturiratne
authors.forename: Mark
authors.initials: M
authors.lastname: Simmonds
mesh_terms: D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000188:drug therapy* / Q000503:physiopathology; D004359:Drug Therapy, Combination; D005492:Folic Acid / Q000627:therapeutic use*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome; D014803:Vitamin B Complex / Q000627:therapeutic use*
chemical_list: D014803:Vitamin B Complex; D005492:Folic Acid