Nation-Wide Prevalence Of Wheezing By Using Isaac Questionnaire From Pre-School Children To Adolescents In Japan

RATIONALE: We investigated nation-wide prevalence of wheezing from pre-school children to adolescents in Japan. METHODS: Cross sectional survey of pre-school children (3 to 6 year old), elementary school students (6 to 8 year old), junior high school students (13 to 15 year old) and senior high school students (16 to 18 year old) was carried out using ISAAC written questionnaire. More than 48,000 children from each age group were randomly selected. RESULTS: Response rate was 92% (n = 47,291) in pre-school children, and 87% (n = 44,110) in elementary school students, 74% (n = 49,898) in junior high school students and 77% (n = 55,096) in senior high school students. The prevalence of wheezing in the last 12 months was 19.9%, 13.6%, 9.6% and 8.3%, respectively. The prevalence of frequent wheezing episodes (>12 wheezing episodes) in the last 12 months was 0.6%, 0.5%, 0.8% and 0.8%, respectively. The prevalence of wheezing in the last 12 months in boys was higher than that in girls in pre-school children (23.2% vs. 16.6%) and elementary school students (15.8% vs. 11.4%). There was no difference in that between boys and girls in junior high school students (9.7% vs. 9.4%) and senior high school students (8.4% vs. 8.2%). CONCLUSIONS: The prevalence of wheezing in the last 12 months in younger children was higher than that in adolescents, but the prevalence of frequent wheezing in adolescents was higher than that in younger children. The prevalence of wheezing in the last 12 months in boys was higher than that in girls in younger children.