Role of urbanization and air pollution in adolescent asthma: A mass screening in Taiwan

Background and Purpose: The prevalence of asthma in school children in Taiw an is increasing. This study used mass screening among middle school childr en in Taiwan to determine the prevalence of asthma and related factors. Methods: Data were collected from parents using a self-reported questionnai re and from children using the International Study of Asthma and Allergies in Childhood (ISAAC) video questionnaire. Six study teams conducted the sur vey nationwide in 1995-1996, with the assistance of middle school nurses an d teachers. Results. Among the 1,018,031 students at 795 middle schools who returned qu estionnaires, 8.5% had a history of asthma (ranging in prevalence from 4.2% to 13% in 25 areas). The prevalence of asthma was higher in boys than in g irls (10.0% vs 7%) and was highest in more urbanized areas (11.2%), followe d by moderately urbanized areas (7.4%) and less urbanized and rural areas ( 6.5%), Controlling for age, family smoking, family incense burning, and par ental education level, multivariate logistic regression models indicated th at children living in an area with heavy air pollution were more likely to have asthma than those in an area with no or light pollution (odds ratio, O R = 2.01 arid 95% confidence interval, Cl = 1.94-2.09 based on parental ran king of pollution level, or OR = 1.30 and 95% Cl = 1.18-1.42 based on pollu tion level reported by the Environmental Protection Administration). Conclusions: Adolescent asthma in Taiwan is most prevalent in the most urba nized areas and decreases in prevalence in less urbanized areas. This study also found that higher parental education level and higher area air pollut ion were associated with higher adolescent asthma prevalence.