[A study on the prevalence of bronchial asthma in school children in western districts of Japan--comparison between the studies in 1982 and in 1992 with the same methods and same districts. The Study Group of the Prevalence of Bronchial Asthma, the West Japan Study Group of Bronchial Asthma].

UNLABELLED: The prevalence of bronchial asthma in school children was examined both in 1982 (55,388 children) and in 1992 (45,674 children) in 11 western districts of Japan. Both studies were conducted with the same Japanese version of a modified ATS-DLD children's questionnaire in the same districts.
RESULTS: 1) The study in 1992 established a prevalence rate of 5.6% in males and 3.5% in females with an overall average of 4.6%, which was 1.4 times higher than that of 10 years ago. The higher prevalence was observed in every grade of school children and in all districts. 2) The study in 1992 showed no differences based on the grades of the school children were in. The prevalence rate in males was 1.6 times higher than that in females with fewer regional differences than in the 1982 study. 3) Higher prevalence rates were found in those who had histories of respiratory diseases during their infancy, family histories of allergic disease or who lived in urban areas. The prevalence rate was 13.3% in children living in urban areas with family histories of bronchial asthma. 4) The prevalence rate of wheezing was 5.2%, which was 1.3 times higher than that of 10 years ago. The rate had increased in every district, but it decreased as the children moved into higher grades.