Prevalence and Severity of Food Allergies Among US Adults

Abstract

Importance: Food allergy is a costly, potentially life-threatening condition. Although studies have examined the prevalence of childhood food allergy, little is known about prevalence, severity, or health care utilization related to food allergies among US adults.

Objective: To provide nationally representative estimates of the distribution, severity, and factors associated with adult food allergies.

Design, setting, and participants: In this cross-sectional survey study of US adults, surveys were administered via the internet and telephone from October 9, 2015, to September 18, 2016. Participants were first recruited from NORC at the University of Chicago's probability-based AmeriSpeak panel, and additional participants were recruited from the non-probability-based Survey Sampling International (SSI) panel.

Exposures: Demographic and allergic participant characteristics.

Main outcomes and measures: Self-reported food allergies were the main outcome and were considered convincing if reported symptoms to specific allergens were consistent with IgE-mediated reactions. Diagnosis history to specific allergens and food allergy-related health care use were also primary outcomes. Estimates were based on this nationally representative sample using small-area estimation and iterative proportional fitting methods. To increase precision, AmeriSpeak data were augmented by calibration-weighted, non-probability-based responses from SSI.

Results: Surveys were completed by 40 443 adults (mean [SD] age, 46.6 [20.2] years), with a survey completion rate of 51.2% observed among AmeriSpeak panelists (n = 7210) and 5.5% among SSI panelists (n = 33 233). Estimated convincing food allergy prevalence among US adults was 10.8% (95% CI, 10.4%-11.1%), although 19.0% (95% CI, 18.5%-19.5%) of adults self-reported a food allergy. The most common allergies were shellfish (2.9%; 95% CI, 2.7%-3.1%), milk (1.9%; 95% CI, 1.8%-2.1%), peanut (1.8%; 95% CI, 1.7%-1.9%), tree nut (1.2%; 95% CI, 1.1%-1.3%), and fin fish (0.9%; 95% CI, 0.8%-1.0%). Among food-allergic adults, 51.1% (95% CI, 49.3%-52.9%) experienced a severe food allergy reaction, 45.3% (95% CI, 43.6%-47.1%) were allergic to multiple foods, and 48.0% (95% CI, 46.2%-49.7%) developed food allergies as an adult. Regarding health care utilization, 24.0% (95% CI, 22.6%-25.4%) reported a current epinephrine prescription, and 38.3% (95% CI, 36.7%-40.0%) reported at least 1 food allergy-related lifetime emergency department visit.

Conclusions and relevance: These data suggest that at least 10.8% (>26 million) of US adults are food allergic, whereas nearly 19% of adults believe that they have a food allergy. Consequently, these findings suggest that it is crucial that adults with suspected food allergy receive appropriate confirmatory testing and counseling to ensure food is not unnecessarily avoided and quality of life is not unduly impaired.

Figure 1.. Convincing, Physician-Diagnosed, and Severe Food Allergy (FA) Categorization Flow Diagram

Stringent symptoms by organ system include skin or oral mucosa (hives, swelling [except lip or tongue], lip or tongue swelling, difficulty swallowing, throat tightening), respiratory tract (chest tightening, trouble breathing, wheezing), gastrointestinal tract (vomiting), and cardiovascular (chest pain, rapid heartbeat, fainting, low blood pressure). Gastrointestinal symptoms commonly associated with intolerance (eg, diarrhea, cramps) were not considered to be stringent symptoms. The following allergies were considered for exclusion as probable oral allergy syndrome (OAS) based on symptom report: fruit, vegetable, peanut, tree nut, wheat, soy, barley, rice, seed, spice, shellfish, and fin fish.

Figure 2.. Factors Associated With Current Food Allergy

Each square represents the odds ratio (OR) point estimate for each corresponding variable or sample characteristic, adjusting for all other variables in the logistic regression model. Each horizontal line represents the 95% CI. Percentages of all adults in each subgroup and adults with current food allergies in each subgroup are given in eTable 1 in the Supplement. ^aCompared with the reference group. ^bReference group. ^cEducational attainment was modeled as a continuous variable with the following 7 categories: less than high school, high school, some college, associates, bachelors, masters, and professional or doctorate. ^dThe reference group for each comorbid condition is the absence of that condition.