The use and interpretation of serum retinol distributions in evaluating the public health impact of vitamin A programmes

Amanda C. Palmer, Keith P. West, Nita Dalmiya, Werner Schultink

Research output: Contribution to journalReview article

Abstract

Objective Developing countries have adopted universal, high-potency vitamin A (VA) supplementation and food fortification as major strategies to control deficiency, prevent nutritional blindness and reduce child mortality. Yet questions persist regarding how best to measure impact and when to phase out supplementation. The present paper provides guidance on the use and interpretation of serum retinol (SROL) distributions as indicators of both programme impact and adequate VA intake in a population. Design We reviewed extant data on SROL's response to high-potency VA supplementation and VA-fortified foods in children. Results Supplementation virtually eliminates xerophthalmia and reduces child mortality; however, it shifts the SROL distribution only transiently (<2 months). Regular consumption of VA-fortified foods prevents xerophthalmia, lowers mortality and sustainably improves SROL distributions, from which both compliance and public health impact can be inferred. Conclusions Given SROL's limited responsiveness to high-potency VA supplementation, target population coverage remains the preferred performance indicator. However, periodic SROL surveys do reflect underlying dietary risk and can guide programming: low or marginal SROL distributions in areas with high supplementation coverage do not signify programme failure, but rather suggest the need to continue supplementation while working to effectively raise dietary VA intakes. We propose that a sustained rise in the SROL distribution, defined as ?5 % prevalence of SROL < 0·70 μmol/l among vulnerable population groups in at least two consecutive surveys (≥1 year apart), be used as an indicator of stable and adequate dietary VA intake and status in a population, at which point programmes may re-evaluate the need for continued universal supplementation.

Original languageEnglish (US)
Pages (from-to)1201-1215
Number of pages15
JournalPublic health nutrition
Volume15
Issue number7
DOIs
StatePublished - Jul 1 2012

Keywords

  • Assessment
  • Deficiency
  • Fortification
  • Supplementation
  • Vitamin A

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health

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