title: Determinants of vitamin a deficiency in children between 6 months and 2 years of age in Guinea-Bissau.
abstract: BACKGROUND
  The World Health Organization (WHO) classifies Guinea-Bissau as having severe vitamin A deficiency (VAD). To date, no national survey has been conducted. We assessed vitamin A status among children in rural Guinea-Bissau to assess status and identify risk factors for VAD.
  
  
  METHODS
  In a vitamin A supplementation trial in rural Guinea-Bissau, children aged 6 months to 2 years who were missing one or more vaccines were enrolled, vaccinated and randomized to vitamin A or placebo. Provided consent, a dried blood spot (DBS) sample was obtained from a subgroup of participants prior to supplementation. Vitamin A status and current infection was assessed by an ELISA measuring retinol-binding protein (RBP) and C-reactive protein (CRP). VAD was defined as RBP concentrations equivalent to plasma retinol <0.7 μmol/L; infection was defined as CRP >5 ml/L. In Poisson regression models providing prevalence ratios (PR), we investigated putative risk factors for VAD including sex, age, child factors, maternal factors, season (rainy: June-November; dry: December-May), geography, and use of health services.
  
  
  RESULTS
  Based on DBS from 1102 children, the VAD prevalence was 65.7% (95% confidence interval 62.9-68.5), 11% higher than the WHO estimate of 54.7% (9.9-93.0). If children with infection were excluded, the prevalence was 60.2% (56.7-63.7). In the age group 9-11 months, there was no difference in prevalence of VAD among children who had received previous vaccines in a timely fashion and those who had not. Controlled for infection and other determinants of VAD, the prevalence of VAD was 1.64 (1.49-1.81) times higher in the rainy season compared to the dry, and varied up to 2-fold between ethnic groups and regions. Compared with having an inactivated vaccine as the most recent vaccine, having a live vaccine as the most recent vaccination was associated with lower prevalence of VAD (PR=0.84 (0.74-0.96)).
  
  
  CONCLUSIONS
  The prevalence of VAD was high in rural Guinea-Bissau. VAD varied significantly with season, ethnicity, region, and vaccination status.
  
  
  BACKGROUND
  Clinicaltrials.gov NCT00514891.
authors: Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Orestads Boulevard, Copenhagen S 2300, Denmark. nds@bio.ku.dk
authors: Niels
authors: N
authors: Danneskiold-Samsøe
authors: Ane Bærent
authors: AB
authors: Fisker
authors: Mathias Jul
authors: MJ
authors: Jørgensen
authors: Henrik
authors: H
authors: Ravn
authors: Andreas
authors: A
authors: Andersen
authors: Ibraima Djogo
authors: ID
authors: Balde
authors: Christian
authors: C
authors: Leo-Hansen
authors: Amabelia
authors: A
authors: Rodrigues
authors: Peter
authors: P
authors: Aaby
authors: Christine Stabell
authors: CS
authors: Benn
mesh_terms: D002675:Child, Preschool; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006169:Guinea-Bissau / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D012307:Risk Factors; D012423:Rural Health / Q000706:statistics & numerical data*; D012621:Seasons; D014611:Vaccination / Q000706:statistics & numerical data; D014802:Vitamin A Deficiency / Q000453:epidemiology* / Q000208:ethnology