title: Impact of vitamin A supplementation on infant and childhood mortality.
abstract: BACKGROUND
  Vitamin A is important for the integrity and regeneration of respiratory and gastrointestinal epithelia and is involved in regulating human immune function. It has been shown previously that vitamin A has a preventive effect on all-cause and disease specific mortality in children under five. The purpose of this paper was to get a point estimate of efficacy of vitamin A supplementation in reducing cause specific mortality by using Child Health Epidemiology Reference Group (CHERG) guidelines.
  
  
  METHODS
  A literature search was done on PubMed, Cochrane Library and WHO regional data bases using various free and Mesh terms for vitamin A and mortality. Data were abstracted into standardized forms and quality of studies was assessed according to standardized guidelines. Pooled estimates were generated for preventive effect of vitamin A supplementation on all-cause and disease specific mortality of diarrhea, measles, pneumonia, meningitis and sepsis. We did a subgroup analysis for vitamin A supplementation in neonates, infants 1-6 months and children aged 6-59 months. In this paper we have focused on estimation of efficacy of vitamin A supplementation in children 6-59 months of age. Results for neonatal vitamin A supplementation have been presented, however no recommendations are made as more evidence on it would be available soon.
  
  
  RESULTS
  There were 21 studies evaluating preventive effect of vitamin A supplementation in community settings which reported all-cause mortality. Twelve of these also reported cause specific mortality for diarrhea and pneumonia and six reported measles specific mortality. Combined results from six studies showed that neonatal vitamin A supplementation reduced all-cause mortality by 12 % [Relative risk (RR) 0.88; 95 % confidence interval (CI) 0.79-0.98]. There was no effect of vitamin A supplementation in reducing all-cause mortality in infants 1-6 months of age [RR 1.05; 95 % CI 0.88-1.26]. Pooled results for preventive vitamin A supplementation showed that it reduced all-cause mortality by 25% [RR 0.75; 95 % CI 0.64-0.88] in children 6-59 months of age. Vitamin A supplementation also reduced diarrhea specific mortality by 30% [RR 0.70; 95 % CI 0.58-0.86] in children 6-59 months. This effect has been recommended for inclusion in the Lives Saved Tool. Vitamin A supplementation had no effect on measles [RR 0.71, 95% CI: 0.43-1.16], meningitis [RR 0.73, 95% CI: 0.22-2.48] and pneumonia [RR 0.94, 95% CI: 0.67-1.30] specific mortality.
  
  
  CONCLUSIONS
  Preventive vitamin A supplementation reduces all-cause and diarrhea specific mortality in children 6-59 months of age in community settings in developing countries.
authors.affiliation: Division of Women & Child Health, The Aga Khan University, Karachi, Pakistan.
authors.forename: Aamer
authors.initials: A
authors.lastname: Imdad
authors.forename: Mohammad Yawar
authors.initials: MY
authors.lastname: Yakoob
authors.forename: Christopher
authors.initials: C
authors.lastname: Sudfeld
authors.forename: Batool A
authors.initials: BA
authors.lastname: Haider
authors.forename: Robert E
authors.initials: RE
authors.lastname: Black
authors.forename: Zulfiqar A
authors.initials: ZA
authors.lastname: Bhutta
mesh_terms: D002648:Child; D046688:Child Mortality; D003906:Developing Countries; D003967:Diarrhea / Q000401:mortality / Q000517:prevention & control; D019587:Dietary Supplements; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D017410:Practice Guidelines as Topic; D016032:Randomized Controlled Trials as Topic; D014801:Vitamin A / Q000008:administration & dosage*; D014815:Vitamins / Q000008:administration & dosage*
chemical_list: D014815:Vitamins; D014801:Vitamin A