Impact of regular home allergen intake within no-observed-adverse-effect-level on eliciting dose: 10-year data from a Japanese center

BACKGROUND: Eliciting doses (EDs) are central to food allergy risk assessment. While regular ingestion of allergens within no-observed-adverse-effect-level (NOAEL) is known to promote immunological tolerance, its quantitative effect on EDs remains unclear. This study aimed to evaluate the impact of regular home intake of food allergens within NOAEL on estimated ED values during OFCs. METHODS: We conducted a retrospective study of children undergoing oral food challenges (OFCs) for egg white, cow's milk, peanut, and walnut from 2013 to 2023 at the National Center for Child Health and Development, Japan. Participants were categorized by regular intake of the allergen. Propensity score matching was used to adjust for age, sex, specific IgE levels, and comorbid allergic diseases. EDs were compared between groups using parametric models. This study used an opt-out consent process and was approved by the institutional ethics committee (2023-250). RESULTS: values (mg protein) were higher in the regular intake group than in the no intake group for all allergens, with non-overlapping 95% confidence intervals for egg white, cow's milk, and walnut: egg white (54.7 mg vs. 12.7 mg), milk (10.6 mg vs. 3.3 mg), peanut (12.6 mg vs. 3.3 mg), walnut (21.1 mg vs. 2.7 mg). CONCLUSIONS: Regular allergen intake within NOAEL is associated with higher EDs. These findings may help refine OFC protocols.