IRON deficiency anemia was significantly associated with greater odds of asthma, atopic dermatitis and several allergic conditions. The finding comes from a retrospective, cross-sectional analysis of the National Inpatient Sample from 2016 to 2020, covering 32,966,720 patients. Of those, 1,247,309 (3.8%) had iron deficiency anemia (IDA).
Researchers set out to test whether IDA, a prevalent nutritional deficiency linked to immune modulation, tracks with five allergic diagnoses: atopic dermatitis, asthma, allergic rhinitis, food allergy and allergic eosinophilia.
Logistic regression models adjusted for payer type, race, socioeconomic status and hospital characteristics. After adjustment, IDA was associated with higher odds of every allergic condition studied.
Atopic dermatitis showed the strongest association (odds ratio [OR] 1.30), followed by allergic eosinophilia (OR 1.24). Asthma and allergic rhinitis each had an OR of 1.21, and food allergy had an OR of 1.18.
Although the effect sizes are modest, the association held across five distinct allergic diagnoses in a large, nationally representative dataset. That consistency strengthens the signal, even though it does not establish cause.
The authors conclude that iron status may represent a clinically relevant factor in patients with allergic diseases. For physicians managing atopic dermatitis, asthma, allergic rhinitis or food allergy, iron deficiency anemia may be worth considering as a coexisting nutritional problem.
Because the design is cross-sectional and drawn from hospitalized patients, it cannot show whether iron deficiency anemia contributes to allergic disease, results from it or simply travels with it.
The authors call for longitudinal studies to clarify causal pathways and develop targeted interventions.
They add that addressing nutritional deficiencies may reduce the burden of allergic diseases and improve health outcomes, a possibility that future research will need to test.
Reference
Beniwal SS et al. Association Between Iron Deficiency Anemia and Allergic Conditions: A Retrospective Analysis. Hum Antibodies. 2026. DOI: 10.1177/10932607261495882.
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