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Open Access Research article

Determinants of vitamin a deficiency in children between 6 months and 2 years of age in Guinea-Bissau

Niels Danneskiold-Samsøe12*, Ane Bærent Fisker12, Mathias Jul Jørgensen1, Henrik Ravn1, Andreas Andersen12, Ibraima Djogo Balde2, Christian Leo-Hansen12, Amabelia Rodrigues23, Peter Aaby12 and Christine Stabell Benn12

  • * Corresponding author: Niels Danneskiold-Samsøe nds@bio.ku.dk

Author Affiliations

1 Research Center for Vitamins and Vaccines (CVIVA), Bandim Health Project, Statens Serum Institut, Orestads Boulevard, Copenhagen S 2300, Denmark

2 Bandim Health Project, Indepth Network, Bissau, Apartado 861 1004 Bissau Codex, Guinea-Bissau

3 National Institute of Public Health (INASA), CP 1013, Bissau, Guinea-Bissau

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BMC Public Health 2013, 13:172  doi:10.1186/1471-2458-13-172

Published: 25 February 2013

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.

Trial registration

Clinicaltrials.gov NCT00514891

Keywords:
Vitamin A deficiency; Children; Guinea-Bissau; Risk factors; Retinol-binding protein