More than one in 10 U.S. adults — over 26 million people — have food allergies, but almost twice as many believed they have them, researchers reported.
In a cross-sectional survey of 40,443 U.S. adults, 10.8% reported having symptoms consistent with food allergy, such as a history of severe reaction to the allergic food. But 19% of survey respondents reported having a food allergy, according to Ruchi S. Gupta, MD, MPH, of Northwestern University Feinberg School of Medicine in Chicago, and colleagues.
Just half of adults with convincing food allergies had a physician-confirmed diagnosis, and fewer than one in four reported a current epinephrine prescription, they stated in JAMA Network Open.
In addition, 38.3% of respondents with convincing food allergies had reactions serious enough to end up in hospital emergency departments (ED), the authors noted.
Gupta told MedPage Today that she was surprised to find that almost half of respondents reporting food allergy symptoms consistent with IgE-mediated reactions developed food allergies as adults.
“About one in four, or 27%, reported their first food allergy as an adult,” she said. “Shellfish allergy was by far the most common food among those reporting adult-onset food allergies.”
Gupta said more research is needed to determine if specific environmental triggers play a role in promoting allergic reactions to certain foods among adults who were not previously allergic.
She also noted that while food allergy prevalence has been well documented among children in population-based studies, less has been known about food allergy prevalence in adults.
“There are many other food-related conditions common among adults that may be confused with (systemic) food allergy, such as gluten or milk intolerance or oral allergy syndrome,” she said. “That is why it is so important to get a diagnosis. A good take-home for physicians is that they should ask their patients about this. We routinely ask about medication allergies. It might be a good idea to ask about food as well.”
Cross-sectional surveys were administered via the internet and telephone from October 2015 to September 2016. Participants were recruited from the independent research center NORC at the University of Chicago’s probability-based AmeriSpeak panel and the non-probability based Survey Sampling International (SSI) panel.
The survey completion rate was 51.2% among AmeriSpeak panelists (n = 7,210) and 5.5% among SSI panelists (n=33,233).
The researchers reported that convincing food allergy prevalence was 10.8% (95% CI, 10.4-11.1%), although 19% (95% CI, 18.5-19.5) adults self-reported food allergy.
Shellfish allergies were the most commonly reported food allergy among adults, with survey data indicating that roughly 7.2 million adults are allergic to shellfish. The next most prevalent allergies were to milk (4.7 million), peanuts (4.5 million), tree nuts (3 million), fin fish (2.2 million), eggs (2 million), wheat (2 million), soy (1.5 million), and sesame (0.5 million).
About half of survey respondents with convincing food allergies experienced a severe food allergy reaction (51.1%, 95% CI 49.3%-52.9%) and 45.3% were allergic to multiple foods (95% CI 43.6%-47.1%).
Almost half (48%) developed food allergies as adults, and 38.3% reported at least one food allergy-related ED visit.
The researchers noted that the adult food allergy prevalence estimate of 10.8% falls between the 10% estimated from the 2007-2010 National Health and Nutrition Examination Survey data, and the 13% estimated from 2010 FDA Food Safety Survey data.
“However, neither of these surveys collected data on reaction symptoms that could be used to identify adults reporting food allergies that are unlikely to be IgE mediated,” they wrote. “Given that the most prevalent allergies observed were shellfish and peanuts, which prior pediatric work suggests are infrequently outgrown, this finding suggests that the population-level burden of food allergy is likely to increase in the future, absent widespread implementation of effective prevention efforts and/or therapies.”
The study was funded by the National Institute of Allergy and Infectious Diseases, the Sean Parker Center for Allergy and Asthma Research at Stanford University, Aimmune Therapeutics, and Denise and Dave Bunning.
Gupta and co-authors disclosed no relevant relationships with industry.