PURPOSE OF THE STUDY.
The authors sought to determine whether certain atopic features, sociodemographic characteristics, and lifestyle habits were associated with childhood food allergy.
Through randomized telephone calls, study participants were asked to complete a questionnaire if they had a history of food allergy (cow’s milk, egg, peanut, tree nuts, fish, shellfish, wheat, soy, or sesame). Controls were age-matched, nonallergic individuals either living in the same household or randomly selected.
This was a case-controlled study nested within the SPAACE study (Surveying Prevalence of food Allergy in All Canadian Environments). A random telephone sampling of families were called between September 2010 and September 2011. Cases and controls were matched to 3 age groups: <5 years, 5 to 17 years, and >18 years of age. They aimed to have a ratio of at least 1:4 between cases and controls for each of 3 matched groups. Questionnaires looked at atopic history, sociodemographic patterns, and lifestyle habits.
Four hundred and eighty cases and 4950 controls completed the questionnaire. For all 9 food allergens, having a personal history of eczema in the first 2 years of life, asthma or hay fever, close family member with food allergy, and high household income (>20%) were all associated with a higher risk of probable allergy. Males and older individuals were less likely to have food allergy. Eczema in the first 2 years of life was the strongest risk factor for egg, peanut, tree nut, and fish allergy. Having older siblings and living on a farm were associated with lower risk of milk and egg allergy, respectively.
This large population-based, nested case-control study further confirms previously reported factors associated with increased allergy (higher household income, not having older siblings, and living in urban areas). In addition, eczema during the first 2 years of life, and not during the later years, is consistently associated with food allergies.
Although we know there are lifestyle factors that play a role in atopic sensitization, less clear is whether we can establish prevention strategies to halt the progression of allergy. This large-scale study found that early childhood eczema is associated with food allergies, and the authors suggest that the disrupted skin barrier in atopic dermatitis leads to cutaneous allergenic exposure and may promote food allergen sensitization. Future studies should investigate whether using barrier repair treatments for eczema therapy in these youngsters may halt the development of food allergy.
- Copyright © 2015 by the American Academy of Pediatrics