title: Ambient air pollution and out-of-hospital cardiac arrest.
abstract: BACKGROUND
  Sudden cardiac arrest is a leading cause of cardiovascular death. This study aimed at investigating the impact of short-term exposure to air pollutants on the incidence of OHCA.
  
  
  METHODS
  We identified OHCA cases that occurred in Seoul between 2006 and 2013 from the nationwide emergency medical service database. The association of the daily incidence of OHCA with air pollutants including PM2.5 (particles ≤ 2.5 μm in aerodynamic diameter), PM10, CO, O3, NO2, and SO2 was analyzed with the use of time-series and case-crossover analyses.
  
  
  RESULTS
  A total of 21,509 OHCAs of presumed cardiac origin were identified. An elevation in PM2.5 by 10 μg/m(3) at a moving average of lag 1 and 2 days was shown to increase the risk of OHCA by 1.30% (95% confidence intervals, 0.20-2.41%). An exposure-response relationship was present: the risk of OHCA increased significantly with even a mild elevation of PM2.5 (10-15 μg/m(3)) and further increased with higher levels. While PM10, NO2, CO, and SO2 also showed significant associations with OHCA in single-pollutant models, only PM2.5 remained significant after adjustment for other pollutants. Subgroup analyses showed male sex, advanced age, hypertension, diabetes, heart disease, and history of stroke were risk factors for OHCA in response to elevations in PM2.5.
  
  
  CONCLUSIONS
  This study showed that increased ambient levels of PM2.5 were significantly associated with increased risk of OHCA within 1 to 2 days of exposure, which had a dose-response relationship. Subjects with conventional cardiovascular risk factors were more susceptible to harm of PM2.5.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Si-Hyuck
authors.initials: SH
authors.lastname: Kang
authors.affiliation: Department of Environmental Health and Institute of Health and Environment, Graduate School of Public Health, Seoul National University, Seoul, Korea.
authors.forename: Jongbae
authors.initials: J
authors.lastname: Heo
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Il-Young
authors.initials: IY
authors.lastname: Oh
authors.affiliation: Laboratory of Emergency Medical Services, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jungeun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Boramae Medical Center, Seoul, Korea.
authors.forename: Woo-Hyun
authors.initials: WH
authors.lastname: Lim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Youngjin
authors.initials: Y
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Eue-Keun
authors.initials: EK
authors.lastname: Choi
authors.affiliation: Department of Environmental Health and Institute of Health and Environment, Graduate School of Public Health, Seoul National University, Seoul, Korea.
authors.forename: Seung-Muk
authors.initials: SM
authors.lastname: Yi
authors.affiliation: Department of Emergency Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Sang
authors.initials: S
authors.lastname: Do Shin
authors.affiliation: Department of Biostatistics and Epidemiology, Graduate School of Public Health & Asian Institute of Energy, Environment, and Sustainability, Seoul National University, Korea.
authors.forename: Ho
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea. Electronic address: seil@snu.ac.kr.
authors.forename: Seil
authors.initials: S
authors.lastname: Oh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects*; D000397:Air Pollution / Q000009:adverse effects / Q000706:statistics & numerical data; D018592:Cross-Over Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000453:epidemiology* / Q000209:etiology; D052638:Particulate Matter / Q000009:adverse effects; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: Air pollution; Epidemiology; Sudden cardiac death