Prevalence and incidence of iron deficiency in European community-dwelling older adults: an observational analysis of the DO-HEALTH trial
Authors: Stahl-Gugger Alenka , de Godoi Rezende Costa Molino Caroline , Wieczorek Maud , Chocano-Bedoya Patricia O. , Abderhalden Lauren A. , Schaer Dominik J. , Spahn Donat R. , Orav E. John , Vellas Bruno , da Silva José A. P. , Kressig Reto W. , Egli Andreas , Bischoff-Ferrari Heike A. ,   for the DO-HEALTH Research Group, Bischoff-Ferrari Heike A. , Egli Andreas , Vellas Bruno , Guyonnet Sophie , Rizzoli René , Biver Emmanuel , Merminod Fanny , Kressig Reto W. , Bridenbaugh Stephanie , Suhm Norbert , Silva José A. P. , Duarte Cátia C. M. , Felsenberg Dieter , Börst Hendrikje , Armbrecht Gabriele , Blauth Michael , Spicher Anna , Felson David T. , Kanis John A. , Mccloskey Eugene V. , Johansson Elena , Watzl Bernhard , Hofbauer Lorenz , Tsourdi Elena , Rauner Martina , Siebert Uwe , Kanis John A. , Ferrari Stephen M. , Gut Benno , Ba Marième , Etheve Stéphane , Eggersdorfer Manfred , Reuschling Monika , Orav Endel J. , Willett Walter C. , Manson JoAnn E. , Dawson-Hughes Bess , Staehelin Hannes B. , Walter Paul W. , Dick Walter , Fried Michael , Eckardstein Arnold , Theiler Robert , Simmen Hans-Peter , Langhans Wolfgang , Zinkernagel Annelies , Mueller Nicolas , Distler Oliver , Graetz Klaus , Nitschke Ina , Dietrich Thomas , Baer Walter , Landau Klara , Ruschitzka Frank , Manz Markus , Burckhardt Peter 
Published: March 2022

Background and aim

Iron deficiency is associated with increased morbidity and mortality in older adults. However, data on its prevalence and incidence among older adults is limited. The aim of this study was to investigate the prevalence and incidence of iron deficiency in European community-dwelling older adults aged ≥ 70 years.

Methods

Secondary analysis of the DO-HEALTH trial, a 3-year clinical trial including 2157 community-dwelling adults aged ≥ 70 years from Austria, France, Germany, Portugal and Switzerland. Iron deficiency was defined as soluble transferrin receptor (sTfR) > 28.1 nmol/L. Prevalence and incidence rate (IR) of iron deficiency per 100 person-years were examined overall and stratified by sex, age group, and country. Sensitivity analysis for three commonly used definitions of iron deficiency (ferritin < 45 μg/L, ferritin < 30 μg/L, and sTfR–ferritin index > 1.5) were also performed.

Results

Out of 2157 participants, 2141 had sTfR measured at baseline (mean age 74.9 years; 61.5% women). The prevalence of iron deficiency at baseline was 26.8%, and did not differ by sex, but by age (35.6% in age group ≥ 80, 29.3% in age group 75–79, 23.2% in age group 70–74);P < 0.0001)and country (P = 0.02), with the highest prevalence in Portugal (34.5%) and the lowest in France (24.4%). As for the other definitions of iron deficiency, the prevalence ranged from 4.2% for ferritin < 30 µg/L to 35.3% for sTfR–ferritin index > 1.5. Occurrences of iron deficiency were observed with IR per 100 person-years of 9.2 (95% CI 8.3–10.1) and did not significantly differ by sex or age group. The highest IR per 100 person-years was observed in Austria (20.8, 95% CI 16.1–26.9), the lowest in Germany (6.1, 95% CI 4.7–8.0). Regarding the other definitions of iron deficiency, the IR per 100 person-years was 4.5 (95% CI 4.0–4.9) for ferritin < 45 µg/L, 2.4 (95% CI 2.2–2.7) for ferritin < 30 µg/L, and 12.2 (95% CI 11.0–13.5) for sTfR–ferritin index > 1.5.

Conclusions

Iron deficiency is frequent among relatively healthy European older adults, with people aged ≥ 80 years and residence in Austria and Portugal associated with the highest risk.