title: Short-term Effects of Ambient Air Pollution on Emergency Department Visits for Asthma: An Assessment of Effect Modification by Prior Allergic Disease History.
abstract: OBJECTIVE
  The goal of this study was to investigate the short-term effect of ambient air pollution on emergency department (ED) visits in Seoul for asthma according to patients' prior history of allergic diseases.
  
  
  METHODS
  Data on ED visits from 2005 to 2009 were obtained from the Health Insurance Review and Assessment Service. To evaluate the risk of ED visits for asthma related to ambient air pollutants (carbon monoxide [CO], nitrogen dioxide [NO2], ozone [O3], sulfur dioxide [SO2], and particulate matter with an aerodynamic diameter <10 μm [PM10]), a generalized additive model with a Poisson distribution was used; a single-lag model and a cumulative-effect model (average concentration over the previous 1-7 days) were also explored. The percent increase and 95% confidence interval (CI) were calculated for each interquartile range (IQR) increment in the concentration of each air pollutant. Subgroup analyses were done by age, gender, the presence of allergic disease, and season.
  
  
  RESULTS
  A total of 33 751 asthma attack cases were observed during the study period. The strongest association was a 9.6% increase (95% CI, 6.9% to 12.3%) in the risk of ED visits for asthma per IQR increase in O3concentration. IQR changes in NO2and PM10concentrations were also significantly associated with ED visits in the cumulative lag 7 model. Among patients with a prior history of allergic rhinitis or atopic dermatitis, the risk of ED visits for asthma per IQR increase in PM10concentration was higher (3.9%; 95% CI, 1.2% to 6.7%) than in patients with no such history.
  
  
  CONCLUSIONS
  Ambient air pollutants were positively associated with ED visits for asthma, especially among subjects with a prior history of allergic rhinitis or atopic dermatitis.
authors.affiliation: Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Juhwan
authors.identifier: 0000-0003-0657-0082
authors.initials: J
authors.lastname: Noh
authors.affiliation: Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jungwoo
authors.initials: J
authors.lastname: Sohn
authors.affiliation: Department of Occupational and Environmental Medicine, Gachon University Gil Hospital, Incheon, Korea.
authors.forename: Jaelim
authors.initials: J
authors.lastname: Cho
authors.affiliation: Department of Medical Informatics and Biostatistics, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seong-Kyung
authors.initials: SK
authors.lastname: Cho
authors.affiliation: Health Insurance Review and Assessment Service, Seoul, Korea.
authors.forename: Yoon Jung
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Changsoo
authors.identifier: 0000-0002-5940-5649
authors.initials: C
authors.lastname: Kim
authors.affiliation: Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.|Institute for Environmental Research, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dong Chun
authors.initials: DC
authors.lastname: Shin
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D001249:Asthma / Q000175:diagnosis* / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D003876:Dermatitis, Atopic / Q000473:pathology; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010126:Ozone / Q000633:toxicity; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D065631:Rhinitis, Allergic / Q000473:pathology; D012306:Risk; D012621:Seasons; D012737:Sex Factors; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D010126:Ozone
keywords: Air pollution; Asthma; Effect modifier; Emergencies; Korea; Time series analysis