title: Effect of Vitamin D on falls: a meta-analysis.
abstract: BACKGROUND
  Falls among elderly individuals occur frequently, increase with age, and lead to substantial morbidity and mortality. The role of vitamin D in preventing falls among elderly people has not been well established.
  
  
  OBJECTIVE
  To assess the effectiveness of vitamin D in preventing an older person from falling.
  
  
  METHODS
  MEDLINE and the Cochrane Controlled Trials Register from January 1960 to February 2004, EMBASE from January 1991 to February 2004, clinical experts, bibliographies, and abstracts. Search terms included trial terms: randomized-controlled trial or controlled-clinical trial or random-allocation or double-blind method, or single-blind method or uncontrolled-trials with vitamin D terms: cholecalciferol or hydroxycholecalciferols or calcifediol or dihydroxycholecalciferols or calcitriol or vitamin D/aa[analogs & derivates] or ergocalciferol or vitamin D/bl[blood]; and with accidental falls or falls, and humans.
  
  
  METHODS
  We included only double-blind randomized, controlled trials (RCTs) of vitamin D in elderly populations (mean age, 60 years) that examined falls resulting from low trauma for which the method of fall ascertainment and definition of falls were defined explicitly. Studies including patients in unstable health states were excluded. Five of 38 identified studies were included in the primary analysis and 5 other studies were included in a sensitivity analysis.
  
  
  METHODS
  Independent extraction by 3 authors using predefined data fields including study quality indicators.
  
  
  RESULTS
  Based on 5 RCTs involving 1237 participants, vitamin D reduced the corrected odds ratio (OR) of falling by 22% (corrected OR, 0.78; 95% confidence interval [CI], 0.64-0.92) compared with patients receiving calcium or placebo. From the pooled risk difference, the number needed to treat (NNT) was 15 (95% CI, 8-53), or equivalently 15 patients would need to be treated with vitamin D to prevent 1 person from falling. The inclusion of 5 additional studies, involving 10 001 participants, in a sensitivity analysis resulted in a smaller but still significant effect size (corrected RR, 0.87; 95% CI, 0.80-0.96). Subgroup analyses suggested that the effect size was independent of calcium supplementation, type of vitamin D, duration of therapy, and sex, but reduced sample sizes made the results statistically nonsignificant for calcium supplementation, cholecalciferol, and among men.
  
  
  CONCLUSIONS
  Vitamin D supplementation appears to reduce the risk of falls among ambulatory or institutionalized older individuals with stable health by more than 20%. Further studies examining the effect of alternative types of vitamin D and their doses, the role of calcium supplementation, and effects in men should be considered.
authors.affiliation: Division of Aging, Department of Medicine, Center for Cardiovascular Disease Prevention, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass 02120, USA. hbischof@hsph.harvard.edu
authors.forename: Heike A
authors.initials: HA
authors.lastname: Bischoff-Ferrari
authors.forename: Bess
authors.initials: B
authors.lastname: Dawson-Hughes
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: Hannes B
authors.initials: HB
authors.lastname: Staehelin
authors.forename: Marlet G
authors.initials: MG
authors.lastname: Bazemore
authors.forename: Robert Y
authors.initials: RY
authors.lastname: Zee
authors.forename: John B
authors.initials: JB
authors.lastname: Wong
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control* / Q000706:statistics & numerical data; D000368:Aged; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D014807:Vitamin D / Q000627:therapeutic use*
chemical_list: D014807:Vitamin D