We’ve long known that childhood food allergy and food allergen sensitization are associated with asthma and rhinitis in childhood. However, the associations between childhood food allergy/food allergen sensitization with asthma and rhinitis in adulthood are not well described. In addition, it is unclear whether food allergy and food allergen sensitization show different associations with asthma and rhinitis throughout one’s life. Characterizing this relationship is crucial, given the allergy epidemic and the well-described mutually detrimental relationship between food allergy and asthma.
To address this gap in knowledge, our study team investigated the longitudinal relationship between childhood food allergy/food allergen sensitization to common food allergens with asthma and rhinitis at ages 18 and 26 in a birth cohort for a paper published in Pediatric Allergy and Immunology.
Food Allergy & Sensitization Evaluated
Study participants (n = 1,456) were followed-up at fixed time points, from ages 1-26, for food allergy/food allergen sensitization status. Food allergy was evaluated at all time points, namely ages 1, 2, 4, 10, 18, and 26. Sensitization status was determined using skin prick tests to common food allergens, performed routinely from age 4 onward; at ages 1 and 2, skin prick tests were only performed if clinically indicated. Asthma and rhinitis were evaluated from age 4 onward and were based on physician diagnoses. Associations between food allergy/food allergen sensitization with asthma and rhinitis were assessed with univariate analyses and then multivariable logistic regression, adjusting for clinically relevant co-variates. These potential categorical covariates included sex, eczema at the corresponding age, family history of asthma, rhinitis, eczema, food allergy, cord Immunoglobulin E, maternal smoking, and socioeconomic status.
Since early aeroallergen sensitization showed a high overlap with food allergy and food allergen sensitization, it was not included in our models as a covariate to avoid collinearity. Covariates trending toward significance in univariate analyses were treated as candidate independent variables and included in the final models of logistic regressions.
We found that childhood food allergy and, particularly, food allergen sensitization were independently associated with asthma in adulthood, even after adjustment for relevant covariates (Table). Food allergy at age 4 was significantly associated with asthma at age 18 (aOR, 2.75; 95% CI, 1.53-4.92) and age 26 (aOR, 2.62; 95% CI, 1.32-5.20). Additionally, food allergy at age 1 or 2 was also associated with asthma at age 26 (aOR, 2.00; 95% CI, 1.14-3.49). However, food allergy at age 10 was not associated with asthma in adulthood. Additionally, childhood food allergy was not significantly associated with adulthood rhinitis.
Food allergen sensitization at ages 4 and 10 was associated with both asthma and rhinitis; however, the associations between food allergen sensitization and rhinitis were less robust relative to asthma. Specifically, food allergen sensitization at age 4 was associated with asthma at ages 18 and 26 but only rhinitis at age 18. Furthermore, food allergen sensitization in symptomatic children at age 1 or 2 was only associated with asthma, not rhinitis, in adulthood.
Odds of Asthma in Adulthood Increased Nearly Three-Fold
Taken together, our findings indicate that childhood food allergy increased the odds of asthma during adulthood by nearly three-fold. Additionally, childhood food allergen sensitization was associated with increased odds of asthma and, to a lesser extent, rhinitis in adulthood. These associations were robust and remained despite adjusting for clinically relevant covariates, including eczema. Our findings also highlight the differential associations between childhood food allergy/food allergen sensitization with asthma and rhinitis, which are often thought to be similar disorders in the “one airway, one disease” paradigm.
Given these findings, we suggest that children with food allergy/food allergen sensitization be followed-up to facilitate early detection and intervention of subsequent allergic airways disease, particularly asthma. In addition, our study team would like to see mechanistic studies that investigate the immunologic pathways linking childhood food allergy and food allergen sensitization with asthma/rhinitis. Primary and secondary preventive strategies have been described to reduce the incidence of food allergy. In light of our findings, it would be valuable to follow up these study participants to ascertain whether these strategies have any long-term impact on asthma/rhinitis.