Children With Food Allergy Are at Risk of Lower Lung Function on High-Pollen Days.

Background: Grass pollen exposure is a risk factor for childhood asthma hospital attendances. However, its short-term influence on lung function, especially among those with other allergic conditions, has been less well-studied.
Objective: To investigate this association in a population-based sample of children.
Methods: Within the HealthNuts cohort, 641 children performed spirometry during the grass pollen season. Grass pollen concentration was considered on the day of testing (lag 0), up to 3 days before (lag 1-lag 3), and cumulatively (lag 0-3). We used linear regression to assess the relevant associations and examined potential interactions with current asthma, hay fever or eczema, and food allergy.
Results: Associations were observed only in children with allergic disease (P value for interaction ≤ 0.1). In children with food allergy, grass pollen concentration was associated with a lower ratio of forced expiratory volume in 1 second to forced vital capacity (FEV ₁ /FVC) and lower mid-forced expiratory flows (FEF _25%-75% ) at all lags (eg, at lag 2, FEV ₁ /FVC z-score = -0.50 [95% CI -0.80 to -0.20] and FEF _25%--75% z-score = -0.40 [-0.60 to -0.04] per 20 grains/m ³ pollen increase), and increased bronchodilator responsiveness (BDR) at lag 2 and lag 3 (eg, at lag 2, BDR = (31 [95% CI -0.005 to 62] mL). In children with current asthma, increasing grass pollen concentration was associated with lower FEF _25%-75% and increased BDR, whereas children with current hay fever or eczema had increased BDR only.
Conclusions: A proactive approach needs to be enforced to manage susceptible children, especially those with food allergy, before high-grass pollen days.
(Copyright © 2022 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)