Researchers estimate global food allergy prevalence using standardized methodology
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Key takeaways:
- Researchers used standardized methodology to estimate global food allergy.
- Among kids, prevalence was lowest in Germany and Japan and highest in Canada.
- For adults, rates were lowest in Japan and highest in Italy.
ANAHEIM, Calif. — Researchers of the ASSESS FA study used consistent methodology to calculate symptom-convincing food allergy prevalence across countries, finding that rates varied specifically in North America, Europe and Japan.
Because research reporting food allergy prevalence in various countries have used different methodologies, it has been difficult to compare these rates and understand whether differences exist, Ruchi S. Gupta, MD, MPH, professor of pediatrics and medicine and director of the Center for Food Allergy & Asthma Research at Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children’s Hospital of Chicago, said during her presentation at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.
“Food allergy prevalence rates have varied widely in previous studies due to geographic, socioeconomic, dietary and access to health care factors, as well as differences in study design and assessment tools,” Gupta told Healio. “In most cases, food allergy prevalence rates have been reported for specific age groups or specific allergens. The aim of ASSESS FA was to provide comparable estimates across countries, age groups and food allergens using a standardized and consistent methodology.”
From October 2022 to February 2023, Gupta and colleagues conducted a cross-sectional, international, population-based survey of self-reported data in four age groups: adults (age 18-65 years), adolescents (age 12-17 years) and parents/guardians of young children (age 6 months-5 years) and older children (age 6-11 years). Overall, the survey involved 42,250 children and 40,537 adults from the U.S., Canada, the U.K., France, Germany, Italy, Spain and Japan.
The survey involved a 30-minute questionnaire of self-reported data related to physician diagnosis of food allergy, allergic reaction symptoms, and time between allergen exposure and onset of symptoms. Researchers specially looked at six common allergens: peanuts, milk and/or dairy, shrimp, shellfish, tree nuts and eggs.
Researchers defined a symptom-convincing food allergy as an allergic reaction that involved a list of predefined symptoms — including hives on the body, mouth or throat; lip/tongue or other swelling; throat or chest tightening; shortness of breath; trouble breathing; wheezing; vomiting; and fainting, dizziness or light-headedness — and which occurred within 120 minutes of food exposure.
“It can be very complicated when you're doing self-reported [food allergy] because those symptoms [could] just be something like stomach pain cramps, so that wasn’t included,” Gupta said during her presentation.
Overall, results showed the point prevalence of symptom-convincing food allergy varied among children from 2.4% (95% CI, 1.9%-2.8%) in Germany to 7.5% (95% CI, 6.7%-8.2%) in Canada, and among adults from 2.1% (95% CI, 1.7%-2.5%) in Japan to 6.5% (95% CI, 5.8%-7.4%) in Italy.
When looking at the three groups of children, Canada showed the highest and Germany the lowest point prevalence of children aged 6 months to 5 years (6.9%; 1.8%) and aged 6 to 11 years (6.7%; 2.7%). For children aged 12 to 17 years, Canada again showed the highest point prevalence, whereas Japan showed the lowest (8.7%; 2.6%).
Differences also emerged when looking at specific allergens. For instance, the point prevalence of peanut allergy was 2% (95% CI, 1.6%-2.3%) among children and 1.6% (95% CI, 1.1%-2.1%) among adults in the U.S., as well as 3.9% (95% CI, 3.4%-4.5%) among children and 1.4% (95% CI, 1%-1.8%) among adults in Canada, compared with 0.7% (95% CI, 0.5%-0.9%) among children and 0.3% (95% CI, 0.2%-0.4%) among adults in Japan.
Gupta also noted that these data showed a 1.3% (95% CI, 0.9%-1.7%) prevalence of shellfish allergy among adults in the U.S., which is lower than the 3% rate commonly reported in the literature.
“So there is a little variability, but the data still show the highest [prevalence of shellfish allergy] in the U.S.,” Gupta said, adding that using symptom-convincing food allergy avoids over- and underestimation of food allergy prevalence.
“We always have this discussion of if you’re only going by symptoms and patient reports, are we overestimating?” she said. “But we found in the U.S. and across the world that a lot of kids and adults don’t get a formal diagnosis. They don't get to an allergist. So, what is the best way? There’s underestimation if you only go by physician diagnosis or there’s maybe overestimation if you only go by parent reports. So, the happy medium is convincing symptoms that are agreed upon.”
Overall, these results were not that surprising, Gupta said.
“The FA prevalence rates found in the ASSESS FA were similar to those reported in the literature, with the exception of China,” she told Healio, adding that one region in particular in China showed higher rates that researchers are currently investigating.
Because researchers now have this tool that can be used to determine food allergy prevalence, they plan to look at more countries.
“We will be presenting further results, including the risk stratification framework which defines different food allergy risk profiles based on the clinical severity of food allergy, the prevalence of adult-onset food allergy and the burden of food allergy on patient quality of life,” she said.