title: Estimation of short-term effects of air pollution on stroke hospital admissions in Wuhan, China.
abstract: OBJECTIVE
  High concentrations of air pollutants have been linked to increased incidence of stroke in North America and Europe but not yet assessed in mainland China. The aim of this study is to evaluate the association between stroke hospitalization and short-term elevation of air pollutants in Wuhan, China.
  
  
  METHODS
  Daily mean NO2, SO2 and PM10 levels, temperature and humidity were obtained from 2006 through 2008. Data on stroke hospitalizations (ICD 10: I60-I69) at four hospitals in Wuhan were obtained for the same period. A time-stratified case-crossover design was performed by season (April-September and October-March) to assess effects of pollutants on stroke hospital admissions.
  
  
  RESULTS
  Pollution levels were higher in October-March with averages of 136.1 µg/m(3) for PM10, 63.6 µg/m(3) for NO2 and 71.0 µg/m(3) for SO2 than in April-September when averages were 102.0 µg/m(3), 41.7 µg/m(3) and 41.7 µg/m(3), respectively (p<.001). During the cold season, every 10 µg/m(3) increase in NO2 was associated with a 2.9% (95%C.I. 1.2%-4.6%) increase in stroke admissions on the same day. Every 10 ug/m(3) increase in PM10 daily concentration was significantly associated with an approximate 1% (95% C.I. 0.1%-1.4%) increase in stroke hospitalization. A two-pollutant model indicated that NO2 was associated with stroke admissions when controlling for PM10. During the warm season, no significant associations were noted for any of the pollutants.
  
  
  CONCLUSIONS
  Exposure to NO2 is significantly associated with stroke hospitalizations during the cold season in Wuhan, China when pollution levels are 50% greater than in the warm season. Larger and multi-center studies in Chinese cities are warranted to validate our findings.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Wuhan University, Wuhan, Hubei, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Xiang
authors.forename: Kristen J
authors.initials: KJ
authors.lastname: Mertz
authors.forename: Vincent C
authors.initials: VC
authors.lastname: Arena
authors.forename: Luann L
authors.initials: LL
authors.lastname: Brink
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Xu
authors.forename: Yongyi
authors.initials: Y
authors.lastname: Bi
authors.forename: Evelyn O
authors.initials: EO
authors.lastname: Talbott
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis; D000397:Air Pollution / Q000009:adverse effects*; D002545:Brain Ischemia / Q000453:epidemiology; D002543:Cerebral Hemorrhage / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D004784:Environmental Monitoring; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008685:Meteorological Concepts; D008875:Middle Aged; D052638:Particulate Matter / Q000737:chemistry; D012621:Seasons; D020521:Stroke / Q000453:epidemiology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter