Estimated number of patients with food allergy in Japan: The present status and issues regarding epidemiological investigation

Abstract

Background: The number of patients with food allergy in Japan is increasing year by year, although the precise prevalence of them is not clear. We aimed to determine the estimated number of people with food allergies in Japan and produce new methods of the investigation of them. Methods: We determined the number of people with food allergies using government data and statistics such as demographic statistic and the number of students. Results: In infants, the number of patients with a food allergy was 800000 as per the self-reported prevalence; however, as per the physicians diagnoses, 300000-500000 of them had a food allergy. In students, the self-reported number was 600000, while 350000 cases were diagnosed by physicians. In adults, the consumer agency investigated the patients who visited the hospital with the immediate hypersensitivity. In this study, the participants were limited to patients who visited the hospital. This made the estimation of the overall prevalence of food allergy in Japan. Conclusion: For children, if we add the questionnaire to the existing study, which questions them regarding the symptoms of food allergy, the diagnosis by the physician, and the blood test, we can better investigate the prevalence of food allergies and changing pattern by the year. In adults, we propose that future investigations consisting of the National Health and Nutrition Survey and a comprehensive survey of living conditions should be conducted, because few studies have reported on food allergies.