Background: Continuous epidemiological surveys using consistent methodologies are essential for assessing the prevalence of allergic diseases. In 2021, a cross-sectional survey on allergic diseases was conducted, targeting staff and their families at Designated Allergic Disease Medical Hospitals across 41 prefectures in Japan. By 2022, these hospitals had been established in all 47 prefectures of Japan.
Methods: A prevalence survey of allergic diseases was conducted in 2022 using the same questionnaire as that used in 2021, encompassing hospitals across all 47 prefectures. Age-adjusted prevalence rates were calculated using the 2015 population model for comparison with the 2021 survey data.
Results: The 2022 survey included 76 hospitals and 24,444 participants (males, 10,668; women, 13,776; median age, 35 years; interquartile range, 18–50 years). The overall prevalence of allergic diseases was 63.0% (95% confidence interval:62.3–63.6). Age-adjusted prevalence of a history per 100,000 people for each allergic disease was as follows (; 95% confidence interval): bronchial asthma (13,279; 12,776–13,782), atopic dermatitis (12,786; 12,379–13,193), food allergies (13,143; 12,689–13,596), perennial allergic rhinitis (28,132; 27,673–28,982), pollinosis (38,959; 38,216–39,703), allergic conjunctivitis (19,751; 19,188–20,313), metal allergies (2,111; 1,898–2,325), drug allergies (4,478; 4,149–4,806), and anaphylaxis (1,602; 1,417–1,787). The prevalence of perennial allergic rhinitis, pollinosis, and allergic conjunctivitis was higher than that in 2021.
Conclusions: This survey is the first in Japan to calculate the age-adjusted prevalence of allergic diseases. Moreover, pollinosis is the most common allergic disease in Japan.
