title: Association of ambient air pollution and meteorological factors with primary care visits at night due to asthma attack.
abstract: OBJECTIVE
  The association of outdoor air pollution and meteorological elements with primary care visits at night due to asthma attack was studied.
  
  
  METHODS
  A case-crossover study was conducted in a primary care clinic in Himeji City, Japan. The subjects were 956 children aged 0-14 years who visited the clinic with an asthma attack between the hours of 9 p.m. and 6 a.m. Daily concentrations of particulate matter, ozone, nitrogen dioxide, and a number of meteorological elements were measured, and a conditional logistic regression model was used to estimate odds ratios (ORs) of primary care visits per unit increment of air pollutants or meteorological elements. The analyses took into consideration the effects of seasonality.
  
  
  RESULTS
  Of the 956 children, 73 (7.6 %) were aged <2 years and 417 (43.6 %) were aged 2-5 years. No association between daily ozone levels and primary care visits due to asthma attack at night in the spring or summer was found. An inverse relation between suspended particulate matter and primary care visits due to asthma attack was detected in the winter. ORs in the summer per degree increment in daily mean temperature was 1.31 [95 % confidential interval (CI) 1.09-1.56], and ORs in the autumn per hourly increment in daily hours of sunshine was 0.94 (95 % CI 0.90-0.99).
  
  
  CONCLUSIONS
  The findings of our study fail to support any association between daily mean concentration of air pollutant and primary care visits at night. However, we did find evidence indicating that certain meteorological elements may be associated with primary care visits.
authors: Department of Healthcare Epidemiology, Graduate School of Medicine and Public Health, Kyoto University, Yoshidakonoecho, Sakyo-ku, Kyoto, 606-8501, Japan, yamazaki.shin.6z@kyoto-u.ac.jp.
authors: Shin
authors: S
authors: Yamazaki
authors: Masayuki
authors: M
authors: Shima
authors: Yoshiko
authors: Y
authors: Yoda
authors: Katsumi
authors: K
authors: Oka
authors: Fumitake
authors: F
authors: Kurosaka
authors: Shigeta
authors: S
authors: Shimizu
authors: Hironobu
authors: H
authors: Takahashi
authors: Yuji
authors: Y
authors: Nakatani
authors: Jittoku
authors: J
authors: Nishikawa
authors: Katsuhiko
authors: K
authors: Fujiwara
authors: Yasuyuki
authors: Y
authors: Mizumori
authors: Akira
authors: A
authors: Mogami
authors: Taku
authors: T
authors: Yamada
authors: Nobuharu
authors: N
authors: Yamamoto
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis*; D001249:Asthma / Q000139:chemically induced / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D004781:Environmental Exposure; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009585:Nitrogen Dioxide / Q000032:analysis; D010126:Ozone / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis; D014887:Weather
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D010126:Ozone; D009585:Nitrogen Dioxide
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