Adjusting plasma or serum zinc concentrations for inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project

doi:10.1093/ajcn/nqz304

The American Journal of Clinical Nutrition

Volume 111, Issue 4, April 2020, Pages 927-937

https://doi.org/10.1093/ajcn/nqz304 Get rights and content

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ABSTRACT

Background

The accurate estimation of zinc deficiency at the population level is important, as it guides the design, targeting, and evaluation of nutrition interventions. Plasma or serum zinc concentration (PZC) is recommended to estimate zinc nutritional status; however, concentrations may decrease in the presence of inflammation.

Objectives

We aimed to assess the relation between PZC and inflammation in preschool children (PSC; 6–59 mo) and nonpregnant women of reproductive age (WRA; 15–49 y), and to compare different inflammation adjustment approaches, if adjustment is warranted.

Methods

Cross-sectional data from 13 nationally representative surveys (18,859 PSC, 22,695 WRA) from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project were analyzed. Correlation and decile analyses were conducted, and the following 3 adjustment methods were compared if a consistent negative association between PZC and C-reactive protein (CRP) or α-1-acid glycoprotein (AGP) was observed: 1) exclude individuals with CRP > 5 mg/L or AGP > 1 g/L; 2) apply arithmetic correction factors; and 3) use the BRINDA regression correction (RC) approach.

Results

In 6 of 12 PSC surveys, the estimated prevalence of zinc deficiency increased with increasing CRP deciles, and to a lesser extent, with increasing AGP deciles. In WRA, the association of PZC with CRP and AGP was weak and inconsistent. In the 6 PSC surveys in which adjustment methods were compared, application of RC reduced the estimated prevalence of zinc deficiency by a median of 11 (range: 4–18) percentage points, compared with the unadjusted prevalence.

Conclusions

Relations between PZC and inflammatory markers were inconsistent, suggesting that correlation and decile analyses should be conducted before applying any inflammation adjustments. In populations of PSC that exhibit a significant negative association between PZC and CRP or AGP, application of the RC approach is supported. At this time, there is insufficient evidence to warrant inflammation adjustment in WRA.

Keywords:

zinc

inflammation

micronutrients

nutritional assessment

undernutrition

Abbreviations used:

AGP

α-1-acid glycoprotein

BRINDA

Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia

correction factor

CRP

C-reactive protein

ICF

internal correction factor

IZiNCG

International Zinc Nutrition Consultative Group

LOD

limit of detection

LOQ

limit of quantification

percentage points

PSC

preschool children

PZC

plasma or serum zinc concentration

regression correction

WRA

nonpregnant women of reproductive age 15–49 y.

Cited by (0)

Supported by the Bill & Melinda Gates Foundation grant OPP1158306, Centers for Disease Control and Prevention, Eunice Kennedy Shriver National Institute of Child Health and Human Development, HarvestPlus, and the United States Agency for International Development.

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the CDC.

Supplemental Tables 1–6 and Supplemental Figures 1 and 2 are available from the “Supplementary data” link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/ajcn/.

Data described in the article, code book, and analytic code will be made available upon request pending approval from the BRINDA steering committee and country representatives.

Published in a supplement to The American Journal of Clinical Nutrition. Publication costs for this supplement were defrayed in part by the payment of page charges and supported by the Bill & Melinda Gates Foundation. The Guest Editor for this supplement was Daniel E Roth and has no relevant conflicts to disclose. The opinions expressed in this publication are those of the authors and are not attributable to the sponsors or the publisher, Editor, or Editorial Board of The American Journal of Clinical Nutrition. The Supplement Coordinators for the supplement publication were Parminder S Suchdev and Melissa F Young, Emory University, Atlanta, GA 30322. Supplement Coordinator disclosures: PSS receives salary support from the CDC; MFY, no conflicts to disclose.