Global Nutrition (Poster Theater Flash Session 7)

(PTFS07-04-25) Agreement Between Repeated Hemoglobin and Iron Biomarker Measurements Among Children 2–5 Y of Age in Ghana, and Estimation of “Usual” Deficiency Prevalence

Sunday, June 1, 2025

4:12 PM – 4:16 PM ET

Location: South Hall B (The Hub) - Poster Theater / Poster Board Number PT-4

Presenting Author(s)

Reina Engle-Stone, PhD

Associate Professor
University of California, Davis
Davis, California, United States

Disclosure(s): No relevant financial relationship(s) with ineligible companies to disclose.

Co-Author(s)

CA

Charles D. Arnold, MS

Statistician
University of California, Davis
Davis, California, United States
KW

K. R. Wessells

Institute for Global Nutrition, University of California, Davis
Davis, California, United States
Jennie N. Davis, PhD, RDN (she/her/hers)

Postdoctoral Scholar
University of California, Davis
Bend, Oregon, United States
XT

Xiuping Tan, BS

University of California, Davis
Davis, California, United States
MH

Marjorie J. Haskell, MPH, PhD

Associate Research Nutritionist
University of California, Davis
Davis, California, United States
SK

Sika M. Kumordzie, PhD

Postdoctoral Scholar
University of California, Davis
Kansas City, Missouri, United States
AF

Ahmed D. Fuseini

University of Ghana, Legon
EB

Emily R. Becher, BS (she/her/hers)

PhD Candidate
University of California, Davis
Davis, California, United States
WN

Winifred Nyaaba

University of Ghana, Legon
SV

Stephen A. Vosti, PhD

Adjunct Professor Emeritus
University of California, Davis
St Helena, California, United States
Seth Adu-Afarwuah, Ph.D. (he/him/his)

Head of Department of Nutrition and Food Science
University of Ghana
Accra, Greater Accra, Ghana

Objectives: Biomarker measurements are subject to intra-individual variation but the implications for prevalence assessment are uncertain. We assessed agreement between repeated biomarker measurements (3-wk interval) and whether adjustment for intra-individual variation influenced prevalence estimates.

Methods: Participants were children 24-59 mo of age enrolled in the control group of a trial in northern Ghana, whose households received iodine-fortified bouillon cubes for 9 mo. Children with biomarker data at intervention wks 35 and 38 were included (n=316). Hemoglobin (Hb) was measured in venous blood by Hemocue 301+. Plasma ferritin (Fer) and soluble transferrin receptor (sTfR) were assessed by ELISA; Fer was adjusted for inflammation. Agreement was assessed by Spearman correlations (rho), Bland-Altman plots, and t-tests. We compared anemia (Hb < 11 g/L) and iron deficiency (ID, Fer < 12 μg/L or sTfR > 8.3 mg/L) between time points by Chi-square test and calculated percent agreement. The National Cancer Institute method, via the SIMPLE macro, was used to estimate “usual” biomarker concentration and prevalence of anemia and ID.

Results: Biomarker concentrations at the two time points were correlated (Hb: rho=0.78, Fer: rho=0.84; sTfR: rho=0.91; all P< 0.001) and means did not differ (P >0.05). Anemia was 19.9% at wk35 and 19.1% at wk38, and agreement was 84.5%; 11.6% (n=36) had anemia at both time points. ID based on Fer was 53.2% at wk35, 51.6% at wk38, and agreement was 83.2% (44% with ID at both time points); for sTfR, corresponding values were 52.2%, 51.6%, and 88.6% (46% with ID at both time points). Intra-individual variation comprised 22.1% of total variation in Hb concentration, 17.7% for Fer, and 7.4% for sTfR. Prevalence of anemia based on the estimated “usual” Hb distribution was 20.8%, and “usual” ID was 49.6% for Fer and 57.7% for sTfR.

Conclusions: Repeated measurements of Hb and iron biomarkers and related prevalences showed overall agreement in this sample, although ~11-17% of children changed status after three weeks. Adjusting the biomarker distribution for intra-individual variation had little impact on estimated prevalence of anemia or ID, suggesting that a single measure is sufficient for prevalence estimates.

Funding Sources: Bill & Melinda Gates Foundation, via Helen Keller Intl