title: The impact of different doses of vitamin A supplementation on male and female mortality. A randomised trial from Guinea-Bissau.
abstract: BACKGROUND
  Vitamin A supplementation (VAS) given to children between 6 months and 5 years of age is known to reduce mortality in low-income countries. We have previously observed that girls benefit more from a lower dose of VAS than the one recommended by WHO, the effect being strongest if diphtheria-tetanus-pertussis vaccine (DTP) was the most recent vaccination. We aimed to test these observations.
  
  
  METHODS
  During national immunisations days in Guinea-Bissau, West Africa, combining oral polio vaccination and VAS, we randomised 8626 children between 6 months and 5 years of age to receive the dose of VAS recommended by WHO or half this dose. Mortality rate ratios (MRRs) were assessed after 6 and 12 month.
  
  
  RESULTS
  The overall mortality rate among participants was lower than expected. There was no significant difference in mortality at 6 months and 12 months of follow up between the low dose VAS group and the recommended dose VAS group. The MRRs were 1.23 (0.60-2.54) after 6 months and 1.17 (0.73-1.87) after 12 months. This tendency was similar in boys and girls. The low dose was not associated with lower mortality in girls if the most recent vaccine was DTP (MRR = 0.60 (0.14-2.50) after 6 months).
  
  
  CONCLUSIONS
  Our sample size does not permit firm conclusions since mortality was lower than expected. We could not confirm a beneficial effect of a lower dose of VAS on mortality in girls.
  
  
  BACKGROUND
  The study was registered under clinicaltrials.gov, number NCT00168636.
authors: Bandim Health Project, Indepth Network, Apartado 861, Bissau, Guinea-Bissau. dortheyakymenko@gmail.com
authors: Dorthe
authors: D
authors: Yakymenko
authors: Christine S
authors: CS
authors: Benn
authors: Cesario
authors: C
authors: Martins
authors: Birgitte R
authors: BR
authors: Diness
authors: Ane B
authors: AB
authors: Fisker
authors: Amabelia
authors: A
authors: Rodrigues
authors: Peter
authors: P
authors: Aaby
mesh_terms: D002675:Child, Preschool; D003906:Developing Countries; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006169:Guinea-Bissau / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D009026:Mortality; D011159:Population Surveillance; D017678:Sex Distribution; D014611:Vaccination; D014801:Vitamin A / Q000008:administration & dosage*; D014815:Vitamins / Q000008:administration & dosage*
chemical_list: D014815:Vitamins; D014801:Vitamin A