Rising incidence of chronic allergic disorder in Japan confirmed by large-scale data analysis

In one of the first studies of its kind in Japan, Osaka Metropolitan University-led researchers uncovered the incidence and prevalence of the chronic allergic disorder eosinophilic esophagitis, or EoE.

EoE can cause difficulty in swallowing with tissue inflammation and fibrosis as eosinophils, a type of white blood cell, build up in the esophagus. EoE cases have been increasing in North America and Western Europe since the 1990s, but little has been known about the situation in Asia including Japan.

Dr. Akinari Sawada, Associate Professor Fumio Tanaka, and Professor Yasuhiro Fujiwara of OMU’s Graduate School of Medicine and colleagues analyzed a health insurance claims database spanning January 2005 to September 2022 of 15,200,895 anonymous individuals. These individuals were company employees and their dependents, all under the age of 75. From this data, the research team found 1,010 cases of EoE.

In results published in Clinical Gastroenterology and Hepatology, the researchers assessed the EoE incidence in 2022 as 2.82 per 100,000 person-years and the prevalence as 10.68 per 100,000 people. Compared to 2017 data, the incidence was three times higher and the prevalence was eight times higher.

“In clinical practice, I thought that the number of patients with EoE was likely to increase in Japan. By using large-scale data, we were able to confirm the actual increase in the incidence and prevalence of EoE in this study. We hope that this will lead to raising awareness of EoE in Japan,” said Dr. Sawada.