Prevalence of peanut and tree nut allergy in the US determined by a randomdigit dial telephone survey

Background: Allergy to peanuts and tree nuts (TNs) is one of the leading ca uses of fatal and near-fatal food-induced allergic reactions. These allergi es can be lifelong and appear to be increasing in prevalence. Despite the s eriousness of these allergies, the prevalence of peanut and TN allergy in t he general population is unknown, Objective: We sought to determine the prevalence of peanut and TN allergy a mong the general population of the United States. Methods: We used a nationwide, cross-sectional, random digit dial telephone survey with a standardized questionnaire. Results: A total of 4374 households contacted by telephone participated (pa rticipation rate, 67%), representing 12,032 individuals. Peanut or TN aller gy was self-reported in 164 individuals (1.4%; 95% confidence interval [CI] , 1.2%-1.6%) in 151 households (3.5%; 95% CI, 2.9%-4.0%). The prevalence of reported allergy in adults (1.6%) was higher than that found in children u nder 18 years of age (0.6%). In 131 individuals, details of the reactions w ere obtained, When applying criteria requiring reactions to be typical of I gE-mediated reactions (hives, angioedema, wheezing, throat tightness, vomit ing, and diarrhea) within an hour of ingestion, 10% of these subjects were excluded, Among the remaining 118 subjects, allergic reactions involved I o rgan system (skin, respiratory, or gastrointestinal systems) in 50 subjects , 2 in 45 subjects, and all 3 in 23 subjects. Forty-five percent of these 1 18 respondents reported more than 5 lifetime reactions, Only 53% of these 1 18 subjects ever saw a physician for the allergic reaction, and only 7% had self-injectable epinephrine available at the time of the interview. The pr evalence of peanut and TN allergy was adjusted by assuming that 10% of the remaining 33 subjects without a description of their reactions would also b e excluded and correcting for a 7% false-positive rate for the survey instr ument. A final "corrected" prevalence estimate of 1.1% (95% CI, 1.0%-1.4%) was obtained. Conclusions: Peanut and/or TN allergy affects approximately 1.1% of the gen eral population, or about 3 million Americans, representing a significant h ealth concern. Despite the severity of reactions, about half of the subject s never sought an evaluation by a physician, and only a few had epinephrine available for emergency use.