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

作者：Larson Leila Margaret^*; Addo O Yaw; Sandalinas Fanny; Faigao Katherine; Kupka Roland; Flores Ayala Rafael; Suchdev Parminder S

来源：Maternal and Child Nutrition, 2017, 13(2): UNSP e12298.

DOI：10.1111/mcn.12298

• nutrition
• inflammation
• retinol-binding protein
• vitamin A deficiency
• C-reactive protein
• alpha1-acid glycoprotein

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 35months of age. We compared five approaches to adjust RBP for inflammation and estimate VAD prevalence (defined as RBP < 0.7 mu mol/L): (1) ignoring inflammation; (2) excluding individuals with inflammation (C-reactive protein (CRP) > 5mg/L or alpha1-acid glycoprotein (AGP) > 1g/)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 - beta 1(lnCRPobs-lnCRPref) - beta 2(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 mu mol/L (95% CI: 0.76, 0.82) vs. 0.95 mu mol/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.

• 出版日期2017-4