title: The effect of primary organic particles on emergency hospital admissions among the elderly in 3 US cities.
abstract: BACKGROUND
  Fine particle (PM2.5) pollution related to combustion sources has been linked to a variety of adverse health outcomes. Although poorly understood, it is possible that organic carbon (OC) species, particularly those from combustion-related sources, may be partially responsible for the observed toxicity of PM2.5. The toxicity of the OC species may be related to their chemical structures; however, few studies have examined the association of OC species with health impacts.
  
  
  METHODS
  We categorized 58 primary organic compounds by their chemical properties into 5 groups: n-alkanes, hopanes, cyclohexanes, PAHs and isoalkanes. We examined their impacts on the rate of daily emergency hospital admissions among Medicare recipients in Atlanta, GA and Birmingham, AL (2006-2009), and Dallas, TX (2006-2007). We analyzed data in two stages; we applied a case-crossover analysis to simultaneously estimate effects of individual OC species on cause-specific hospital admissions. In the second stage we estimated the OC chemical group-specific effects, using a multivariate weighted regression.
  
  
  RESULTS
  Exposures to cyclohexanes of six days and longer were significantly and consistently associated with increased rate of hospital admissions for CVD (3.40%, 95%CI = (0.64, 6.24%) for 7-d exposure). Similar increases were found for hospitalizations for ischemic heart disease and myocardial infarction. For respiratory related hospital admissions, associations with OC groups were less consistent, although exposure to iso-/anteiso-alkanes was associated with increased respiratory-related hospitalizations.
  
  
  CONCLUSIONS
  Results suggest that week-long exposures to traffic-related, primary organic species are associated with increased rate of total and cause-specific CVD emergency hospital admissions. Associations were significant for cyclohexanes, but not hopanes, suggesting that chemical properties likely play an important role in primary OC toxicity.
authors: Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. marianthi.anna@mail.harvard.edu.
authors: Marianthi-Anna
authors: MA
authors: Kioumourtzoglou
authors: Antonella
authors: A
authors: Zanobetti
authors: Joel D
authors: JD
authors: Schwartz
authors: Brent A
authors: BA
authors: Coull
authors: Francesca
authors: F
authors: Dominici
authors: Helen H
authors: HH
authors: Suh
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D000407:Alabama / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000139:chemically induced / Q000453:epidemiology*; D002947:Cities; D018592:Cross-Over Studies; D004636:Emergency Service, Hospital; D004781:Environmental Exposure; D004784:Environmental Monitoring; D008401:Gas Chromatography-Mass Spectrometry; D005845:Georgia / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D009930:Organic Chemicals / Q000032:analysis / Q000737:chemistry / Q000633:toxicity; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D012140:Respiratory Tract Diseases / Q000139:chemically induced / Q000453:epidemiology*; D013781:Texas / Q000453:epidemiology
chemical_list: D000393:Air Pollutants; D009930:Organic Chemicals; D052638:Particulate Matter
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