Influence of early-life exposures on food sensitization and food allergy in an inner-city birth cohort

Abstract

Objective: Previous data suggest that food allergy (FA) might be more common in inner-city children; however, these studies have not collected data on both sensitization and clinical reactivity or early-life exposures.

Methods: Children in the Urban Environment and Childhood Asthma birth cohort were followed through age 5 years. Household exposures, diet, clinical history, and physical examinations were assessed yearly; levels of specific IgE to milk, egg, and peanut were measured at 1, 2, 3, and 5 years of age. On the basis of sensitization (IgE ≥0.35 kU/L) and clinical history over the 5-year period, children were classified as having FA or being possibly allergic, sensitized but tolerant, or not allergic/not sensitized.

Results: Five hundred sixteen children were included. Overall, 55.4% were sensitized (milk, 46.7%; egg, 31.0%; and peanut, 20.9%), whereas 9.9% were categorized as having FA (peanut, 6.0%; egg, 4.3%; and milk, 2.7%; 2.5% to >1 food). The remaining children were categorized as possibly allergic (17.0%), sensitized but tolerant (28.5%), and not sensitized (44.6%). Eighteen (3.5%) reported reactions to foods for which IgE levels were not measured. Food-specific IgE levels were similar in children with FA versus sensitized but tolerant children, except for egg, levels of which were higher in patients with FA at ages 1 and 2 years. FA was associated with recurrent wheeze, eczema, aeroallergen sensitization, male sex, breast-feeding, and lower endotoxin exposure in year 1 but not with race/ethnicity, income, tobacco exposure, maternal stress, or early introduction of solid foods.

Conclusions: Even given that this was designed to be a high-risk cohort, the cumulative incidence of FA is extremely high, especially considering the strict definition of FA that was applied and that only 3 common allergens were included.

Keywords: Food allergy; Urban Environment and Childhood Asthma cohort; inner city; specific IgE.

Copyright © 2014 American Academy of Allergy, Asthma & Immunology. All rights reserved.

Figures

Figure 1

The percentage of children classified as Food Allergic (Group 1) during each year of follow-up in the URECA cohort. Children were characterized as Food Allergic if they had serologic and clinical evidence of allergy to the food and documentation of food avoidance during that year.

Figure 2

Differences in food-specific IgE levels between those classified as Group 3 (Sensitized but not Allergic, left panel) and Group 1 (Food Allergic, right panel) at ages 1, 2, 3, and 5. Significant differences (p

Figure 3

Food-specific IgG4 levels among those in Group 4 (green), Group 3 (red), and Group 1 (blue) at ages 1 and 3. Significant differences between groups (P

Figure 4

Odds ratio for development of food allergy (left panel) or food sensitization (right panel) for summary variables of PBMC cytokine response. “Allergic” represents Group 1 (food allergic) versus Groups 3 (sensitized but tolerant) and 4 (not sensitized). “Sensitized” represents Groups 1, 2 (possibly food allergic), and 3 versus 4. Solid circles represent statistical significance in models adjusted for site, gender, season of birth, and family history of atopy. A. Innate panel. B. Adaptive panel. See Supplementary Table E1 for abbreviation definitions and list of stimulants and cytokines measured.

Figure 4

Odds ratio for development of food allergy (left panel) or food sensitization (right panel) for summary variables of PBMC cytokine response. “Allergic” represents Group 1 (food allergic) versus Groups 3 (sensitized but tolerant) and 4 (not sensitized). “Sensitized” represents Groups 1, 2 (possibly food allergic), and 3 versus 4. Solid circles represent statistical significance in models adjusted for site, gender, season of birth, and family history of atopy. A. Innate panel. B. Adaptive panel. See Supplementary Table E1 for abbreviation definitions and list of stimulants and cytokines measured.