Accounting for the influence of inflammation on retinol-binding protein in a population survey of Liberian preschool-age children

Matern Child Nutr. 2017 Apr;13(2):e12298. doi: 10.1111/mcn.12298. Epub 2016 Feb 4.


Vitamin A deficiency (VAD) is an important contributor to child morbidity and mortality. The prevalence of VAD, measured by retinol-binding protein (RBP) or retinol, is overestimated in populations with a high prevalence of inflammation. We aimed to quantify and adjust for the effect of inflammation on VAD prevalence in a nationally representative survey of Liberian children 6 to 35 months of age. We compared five approaches to adjust RBP for inflammation and estimate VAD prevalence (defined as RBP < 0.7 µmol/L): (1) ignoring inflammation; (2) excluding individuals with inflammation (C-reactive protein (CRP) >5 mg/L or alpha1-acid glycoprotein (AGP) >1 g/)L; (3) multiplying each individual's RBP by an internal correction factor; (4) by an external correction factor; and (5) using regression (corrected RBP = exp(InRBP - β1 (lnCRPobs -lnCRPref ) - β2 (lnAGPobs -lnAGPref )). Corrected RBP was based on a regression model where reference lnCRP and lnAGP were set to the maximum of the lowest decile. The unadjusted prevalence of VAD was 24.7%. Children with elevated CRP and/or AGP had significantly lower RBP concentrations than their apparently healthy peers (geometric mean RBP 0.79 µmol/L (95% CI: 0.76, 0.82) vs. 0.95 µmol/L (95% CI: 0.92, 0.97), P < 0.001). Using approaches 2-5 resulted in a prevalence of VAD of 11.6%, 14.3%, 13.5% and 7.3%, respectively. Depending on the approach, the VAD prevalence is reduced 10-17 percentage points when inflammation is taken into account. Further quantification of the influence of inflammation on biomarkers of vitamin A status from other national surveys is needed to compare and recommend the preferred adjustment approach across populations.

Keywords: C-reactive protein; alpha1-acid glycoprotein; inflammation; nutrition; retinol-binding protein; vitamin A deficiency.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers / blood
  • C-Reactive Protein / metabolism
  • Child, Preschool
  • Cross-Sectional Studies
  • Hemoglobins / metabolism
  • Humans
  • Infant
  • Inflammation / epidemiology*
  • Liberia / epidemiology
  • Morbidity
  • Nutritional Status
  • Orosomucoid / metabolism
  • Prevalence
  • Retinol-Binding Proteins / metabolism*
  • Vitamin A / blood
  • Vitamin A Deficiency / blood
  • Vitamin A Deficiency / epidemiology*


  • Biomarkers
  • Hemoglobins
  • Orosomucoid
  • Retinol-Binding Proteins
  • Vitamin A
  • C-Reactive Protein