title: Association between PM2.5 and primary care visits due to asthma attack in Japan: relation to Beijing's air pollution episode in January 2013.
abstract: OBJECTIVE
  In January 2013, extremely high concentrations of fine particles (PM2.5) were observed around Beijing, China. In Japan, the health effects of transboundary air pollution have been a matter of concern. We examined the association between the levels of outdoor PM2.5 and other air pollutants with primary care visits (PCVs) at night due to asthma attack in Himeji City, western Japan.
  
  
  METHODS
  A case-crossover study was conducted in a primary care clinic in Himeji City, Japan, involving 112 subjects aged 0-80 years who visited the clinic due to an asthma attack between 9 p.m. and 6 a.m. during the period January-March, 2013. Daily concentrations of particulate matter, ozone, nitrogen dioxide, and some meteorological elements were measured, and a conditional logistic regression model was used to estimate the odds ratios (OR) of PCVs per unit increment in air pollutants or meteorological elements.
  
  
  RESULTS
  Of the 112 subjects, 76 (68 %) were aged <15 years. We did not note any association between daily PM2.5 levels and PCVs due to asthma attack at night. A positive relation between ozone and PCVs due to asthma attack was detected. The OR per 10 ppb increment in daily mean ozone the day before the visit was 2.31 (95 % confidence interval 1.16-4.61).
  
  
  CONCLUSIONS
  These findings do not support an association between daily mean concentration of PM2.5 and PCVs at night. However, we did find evidence suggesting that ozone is associated with PCVs.
authors.affiliation: Department of Healthcare Epidemiology, Graduate School of Medicine and Public Health, Kyoto University, Yoshidakonoecho, Sakyo-ku, Kyoto, 606-8501, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Yamazaki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shima
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Yoda
authors.forename: Katsumi
authors.initials: K
authors.lastname: Oka
authors.forename: Fumitake
authors.initials: F
authors.lastname: Kurosaka
authors.forename: Shigeta
authors.initials: S
authors.lastname: Shimizu
authors.forename: Hironobu
authors.initials: H
authors.lastname: Takahashi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakatani
authors.forename: Jittoku
authors.initials: J
authors.lastname: Nishikawa
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Mizumori
authors.forename: Akira
authors.initials: A
authors.lastname: Mogami
authors.forename: Taku
authors.initials: T
authors.lastname: Yamada
authors.forename: Nobuharu
authors.initials: N
authors.lastname: Yamamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000032:analysis*; D001249:Asthma / Q000139:chemically induced / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D002681:China; D018592:Cross-Over Studies; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009585:Nitrogen Dioxide / Q000032:analysis; D016017:Odds Ratio; D010126:Ozone / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D014887:Weather; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D010126:Ozone; D009585:Nitrogen Dioxide