Trends in the Prevalence of Childhood Asthma in Seoul Metropolitan City, Korea: The Seoul Atopy ∙ Asthma-friendly School Project

Objectives The project Seoul Atopy ∙ Asthma-friendly School investigated the current status of childhood asthma to enable formulation of a preventative policy. We evaluated the current prevalence of childhood asthma in Seoul and its trends and related factors. Methods The project was conducted annually from 2011 to 2016 and involved around 35 000 children aged 1-13 years. Based on the International Study of Asthma and Allergies in Childhood guidelines, the survey involved parents. The associations of the particulate matter (PM10) concentration, and the number of days on which the daily air quality guidance level was exceeded in the 25 districts of Seoul, with the prevalence of asthma were assessed. Results The age-standardized asthma prevalence in 2011 and 2016 was 6.74 and 4.02%, respectively. The prevalence of lifetime asthma treatment and treatment during the last 12 months tended to decrease from 2011 to 2016. Asthma treatment was significantly correlated with the number of days on which the daily air quality guidance level was exceeded, but not with the PM10 concentration. Conclusions This study reports the prevalence of asthma among children in Seoul and confirmed the relationship between childhood asthma and known risk factors in a large-scale survey