Adjusting soluble transferrin receptor concentrations for inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project

• Type of Material: Article
• Authors: Fabian Rohner, GroundWork; Sorrel ML Namaste, Strengthening Partnerships, Results, and Innovations in Nutrition Globally; Leila M. Larson, Emory University; O. Addo, Emory University; Zuguo Mei, Centers for Disease Control and Prevention; Parminder Suchdev, Emory University; Anne Williams, Emory University; Fayrouz A Sakr Ashour, University of Maryland; Rahul Rawat, International Food Policy Research Institute; Daniel J. Raiten, Eunice Kennedy Shriver National Institute of Child Health and Human Development; Christine A. Northrop-Clewes, Independent Public Health Nutrition Consultant
• Language: English
• Date: 2017-07-01
• Publisher: American Society for Nutrition
• Publication Version: Final Published Version
• Copyright Statement: © 2017 by the American Society for Nutrition
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.3945/ajcn.116.142232
• Title of Journal or Parent Work: American Journal of Clinical Nutrition
• ISSN: 0002-9165
• Volume: 106
• Issue: 1
• Start Page: 372S
• End Page: 382S
• Keywords: C-REACTIVE PROTEIN; VITAMIN-A; BODY IRON; nutritional assessment; Nutrition & Dietetics; Life Sciences & Biomedicine; anemia; ASYMPTOMATIC MALARIA; PRESCHOOL-CHILDREN; ACUTE-PHASE RESPONSE; PLASMA FERRITIN; iron deficiency; Science & Technology; soluble transferrin receptor; IRON-DEFICIENCY ANEMIA; inflammation; WOMEN; PLASMODIUM-FALCIPARUM-INFECTION
• Research Categories: Health Sciences, Nutrition; Health Sciences, Public Health

Abstract

Background: Iron deficiency is thought to be one of the most prevalent micronutrient deficiencies globally, but an accurate assessment in populations who are frequently exposed to infections is impeded by the inflammatory response, which causes iron-biomarker alterations. Objectives: We assessed the relation between soluble transferrin receptor (sTfR) concentrations and inflammation and malaria in preschool children (PSC) (age range: 6-59 mo) and women of reproductive age (WRA) (age range: 15-49 y) and investigated adjustment algorithms to account for these effects. Design: Cross-sectional data from the Biomarkers Reflecting the Inflammation and Nutritional Determinants of Anemia (BRINDA) project from 11,913 PSC in 11 surveys and from 11,173 WRA in 7 surveys were analyzed individually and combined with the use of a meta-analysis. The following 3 adjustment approaches were compared with estimated iron-deficient erythropoiesis (sTfR concentration > 8.3 mg/L): 1) the exclusion of individuals with C-reactive protein (CRP) concentrations > 5 mg/L or α-1-acid glycoprotein (AGP) concentrations > 1 g/L, 2) the application of arithmetic correction factors, and 3) the use of regression approaches. Results: The prevalence of elevated sTfR concentrations incrementally decreased as CRP and AGP deciles decreased for PSC and WRA, but the effect was more pronounced for AGP than for CRP. Depending on the approach used to adjust for inflammation, the estimated prevalence of iron-deficient erythropoiesis decreased by 4.4-14.6 and 0.3-9.5 percentage points in PSC and WRA, respectively, compared with unadjusted values. The correction-factor approach yielded a more modest reduction in the estimated prevalence of iron-deficient erythropoiesis than did the regression approach. Mostly, adjustment for malaria in addition to AGP did not significantly change the estimated prevalence of iron-deficient erythropoiesis. Conclusions: sTfR may be useful to assess iron-deficient erythropoiesis, but inflammation influences its interpretation, and adjustment of sTfR for inflammation and malaria should be considered. More research is warranted to evaluate the proposed approaches in different settings, but this study contributes to the evidence on how and when to adjust sTfR for inflammation and malaria.