Published Online: August 13, 2014
Food allergy is already a common condition, and the number of children diagnosed with food allergy appears to be increasing in industrialized countries. Previous studies have suggested that food allergy may be more common among children living in urban areas, as well as among children of black race/ethnicity. However, these studies relied on self-reported food allergy or food-specific IgE, both of which can overestimate the prevalence of true food allergy. In a recent article published in The Journal of Allergy and Clinical Immunology (JACI), McGowan and colleagues used both clinical data and food-specific IgE values from the Urban Environment and Childhood Asthma (URECA) study to form a strict definition of food allergy and better estimate the prevalence of food allergy in inner-city children. They also looked at whether exposures that are more common in urban environments were risk factors for the development of this condition.
The URECA cohort is a high-risk inner-city birth cohort that was designed to assess the effects of specific urban exposures on the development of recurrent wheeze and asthma. Pregnant women were recruited in Baltimore, Boston, New York City, and St. Louis between 2005 and 2007, and ultimately 609 children were enrolled. For this study, data regarding household exposures, diet, clinical history, physical exams, and food-specific IgE to milk, egg, and peanut were assessed through age 5. Based on clinical symptoms, dietary avoidance, and food-specific IgE levels, children were classified into four groups: 1) Food Allergic, 2) Possibly Food Allergic, 3) Sensitized but Tolerant, and 4) Not Sensitized.
Of the 609 children initially enrolled in URECA, 516 (85%) were included in this study. Overall, 284 children (55.4%) were found to be sensitized to milk, egg (31.0%), or peanut (20.9%) through age 5. Fifty-one children (9.9%) met the criteria for food allergy (milk 2.7%, egg 4.3%, and peanut 6.0%) over the five years. Clinically, children with food allergy were more likely to have recurrent wheeze, eczema, and aeroallergen sensitization. Other risk factors for food allergy included male gender, breastfeeding, and lower endotoxin exposure in the first year of life.
The authors concluded that the cumulative incidence of food allergy in this high-risk inner-city cohort was substantially higher than recent estimates among the general US pediatric population, even using a strict definition of food allergy and focusing on only three major food allergens. This article highlights the need for future studies in this at-risk population and further identification of risk factors for the development of food allergy that might be modifiable.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.