The Impact of Family History of Allergy on Risk of Food Allergy: A Population-Based Study of Infants

The apparent rapid increase in IgE-mediated food allergy and its implications are now widely recognized, but little is known about the relationship between family history (an indirect measure of genetic risk) and the risk of food allergy. In a population-based study of 5,276 one year old infants (HealthNuts), the prevalence of oral food challenge-confirmed food allergy was measured. Associations between family history of allergic disease and food allergy in infants were examined using multiple logistic regression. Food allergy was diagnosed in 534 infants. Compared to those with no family history of allergic disease, children meeting the current definition of "high risk" for allergic disease (one immediate family member with a history of any allergic disease) showed only a modest increase (OR 1.4, 95% CI 1.1-1.7) in food allergy, while having two or more allergic family members was more strongly predictive of food allergy in the child (OR 1.8, 95% CI 1.5-2.3). There were also differences in the associations between family history and egg and peanut allergy in the child. Re-defining "high risk" as two or more allergic family members may be more useful for identification of groups with a significantly increased risk of food allergy both clinically and within research studies.