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 Taiwan is increasing. This study used mass screening among middle school children in Taiwan to determine the prevalence of asthma and related factors. Methods: Data were collected from parents using a self-reported questionnaire and from children using the International Study of Asthma and Allergies in Childhood (ISAAC) video questionnaire. Six study teams conducted the survey nationwide in 1995-1996, with the assistance of middle school nurses and teachers. Results. Among the 1,018,031 students at 795 middle schools who returned questionnaires, 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 girls (10.0% vs 7%) and was highest in more urbanized areas (11.2%), followed by moderately urbanized areas (7.4%) and less urbanized and rural areas (6.5%), Controlling for age, family smoking, family incense burning, and parental education level, multivariate logistic regression models indicated that 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, OR = 2.01 arid 95% confidence interval, Cl = 1.94-2.09 based on parental ranking of pollution level, or OR = 1.30 and 95% Cl = 1.18-1.42 based on pollution level reported by the Environmental Protection Administration). Conclusions: Adolescent asthma in Taiwan is most prevalent in the most urbanized areas and decreases in prevalence in less urbanized areas. This study also found that higher parental education level and higher area air pollution were associated with higher adolescent asthma prevalence.