Nationwide survey of the prevalence of wheeze, rhino-conjunctivitis, and eczema among Japanese children in 2015

Background: Global surveys and cohort studies have been conducted to evaluate the prevalence of allergic disease in childhood, but only a few nationwide surveys have been conducted in Japan. We aimed to report the prevalence of childhood allergic disease in Japan and determine the prevalence distribution by sex and prefecture. Methods: In 2015, we conducted a school-based questionnaire survey using the Japanese version of the International Study of Asthma and Allergies in Childhood questionnaire among two age groups: primary school students (PS, 6-8 years old) and middle school students (MS, 13-15 years old). The schools were randomly selected from each prefecture. Results: Valid responses were obtained from 42,582 PS and 36,638 MS. Among PS and MS, the prevalence of wheeze was 10.2% and 8.2%, that of allergic rhino-conjunctivitis was 18.7% and 26.7%, and that of eczema was 14.6% and 9.7%, respectively. In terms of sex, the prevalence of wheeze and rhino-conjunctivitis was higher in male PS while that of rhino-conjunctivitis and eczema was higher in female MS. In terms of prefecture, there was a two-fold difference in the prevalence of wheeze and eczema and a four-fold difference in the prevalence of rhino-conjunctivitis, with each disease showing different distribution patterns. Conclusions: We demonstrated the prevalence of allergic disease among PS and MS in 2015. The prevalence tended to be higher in male PS and female MS. Each disease exhibited different prevalence ranges and distributions. Identifying the factors behind these differences is a topic for future research. Copyright (C) 2019, Japanese Society of Allergology. Production and hosting by Elsevier B.V.