title: Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis.
abstract: OBJECTIVE
  To determine if vitamin A supplementation is associated with reductions in mortality and morbidity in children aged 6 months to 5 years.
  
  
  METHODS
  Systematic review and meta-analysis. Two reviewers independently assessed studies for inclusion. Data were double extracted; discrepancies were resolved by discussion. Meta-analyses were performed for mortality, illness, vision, and side effects.
  
  
  METHODS
  Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, Medline, Embase, Global Health, Latin American and Caribbean Health Sciences, metaRegister of Controlled Trials, and African Index Medicus. Databases were searched to April 2010 without restriction by language or publication status.
  
  
  METHODS
  Randomised trials of synthetic oral vitamin A supplements in children aged 6 months to 5 years. Studies of children with current illness (such as diarrhoea, measles, and HIV), studies of children in hospital, and studies of food fortification or β carotene were excluded.
  
  
  RESULTS
  43 trials with about 215,633 children were included. Seventeen trials including 194,483 participants reported a 24% reduction in all cause mortality (rate ratio=0.76, 95% confidence interval 0.69 to 0.83). Seven trials reported a 28% reduction in mortality associated with diarrhoea (0.72, 0.57 to 0.91). Vitamin A supplementation was associated with a reduced incidence of diarrhoea (0.85, 0.82 to 0.87) and measles (0.50, 0.37 to 0.67) and a reduced prevalence of vision problems, including night blindness (0.32, 0.21 to 0.50) and xerophthalmia (0.31, 0.22 to 0.45). Three trials reported an increased risk of vomiting within the first 48 hours of supplementation (2.75, 1.81 to 4.19).
  
  
  CONCLUSIONS
  Vitamin A supplementation is associated with large reductions in mortality, morbidity, and vision problems in a range of settings, and these results cannot be explained by bias. Further placebo controlled trials of vitamin A supplementation in children between 6 and 59 months of age are not required. However, there is a need for further studies comparing different doses and delivery mechanisms (for example, fortification). Until other sources are available, vitamin A supplements should be given to all children at risk of deficiency, particularly in low and middle income countries.
authors.affiliation: Centre for Evidence-Based Intervention, Department of Social Policy and Intervention, University of Oxford, UK.
authors.forename: Evan
authors.initials: E
authors.lastname: Mayo-Wilson
authors.forename: Aamer
authors.initials: A
authors.lastname: Imdad
authors.forename: Kurt
authors.initials: K
authors.lastname: Herzer
authors.forename: Mohammad Yawar
authors.initials: MY
authors.lastname: Yakoob
authors.forename: Zulfiqar A
authors.initials: ZA
authors.lastname: Bhutta
mesh_terms: D015982:Bias; D046688:Child Mortality; D002675:Child, Preschool; D003906:Developing Countries; D003967:Diarrhea / Q000453:epidemiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D016239:MEDLINE; D008297:Male; D008457:Measles / Q000453:epidemiology / Q000517:prevention & control; D009017:Morbidity; D009026:Mortality; D009755:Night Blindness / Q000453:epidemiology / Q000517:prevention & control*; D011322:Primary Prevention / Q000379:methods; D016032:Randomized Controlled Trials as Topic; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000517:prevention & control; D014801:Vitamin A / Q000627:therapeutic use*; D014802:Vitamin A Deficiency / Q000188:drug therapy / Q000453:epidemiology / Q000517:prevention & control*; D014839:Vomiting / Q000453:epidemiology / Q000517:prevention & control; D014985:Xerophthalmia / Q000453:epidemiology / Q000517:prevention & control
chemical_list: D014801:Vitamin A