title: Chronic PM2.5 exposure and inflammation: determining sensitive subgroups in mid-life women.
abstract: BACKGROUND
  Several cohort studies report associations between chronic exposure to ambient fine particles (PM2.5) and cardiovascular mortality. Uncertainty exists about biological mechanisms responsible for this observation, but systemic inflammation has been postulated. In addition, the subgroups susceptible to inflammation have not been fully elucidated.
  
  
  METHODS
  We investigated whether certain subgroups are susceptible to the effects of long-term exposure to PM2.5 on C-reactive protein (CRP), a marker of inflammation directly linked to subsequent cardiovascular disease. We used data from the SWAN cohort of 1923 mid-life women with up to five annual repeated measures of CRP. Linear mixed and GEE models accounting for repeated measurements within an individual were used to estimate the effects of prior-year PM2.5 exposure on CRP. We examined CRP as a continuous and as binary outcome for CRP greater than 3mg/l, a level of clinical significance.
  
  
  RESULTS
  We found strong associations between PM2.5 and CRP among several subgroups. For example a 10 µg/m(3) increase in annual PM2.5 more than doubled the risk of CRP greater than 3mg/l in older diabetics, smokers and the unmarried. Larger effects were also observed among those with low income, high blood pressure, or who were using hormone therapy, with indications of a protective effects for those using statins or consuming moderate amounts of alcohol.
  
  
  CONCLUSIONS
  In this study, we observed significant associations between long-term exposure to PM2.5 and CRP in several susceptible subgroups. This suggests a plausible pathway by which exposure to particulate matter may be associated with increased risk of cardiovascular disease.
authors.affiliation: Office of Environmental Health Hazard Assessment, 1515 Clay St, 16th Floor, Oakland, CA, USA. Electronic address: Bart.Ostro@oehha.ca.gov.
authors.forename: Bart
authors.initials: B
authors.lastname: Ostro
authors.affiliation: Office of Environmental Health Hazard Assessment, 1515 Clay St, 16th Floor, Oakland, CA, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Malig
authors.affiliation: Office of Environmental Health Hazard Assessment, 1515 Clay St, 16th Floor, Oakland, CA, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Broadwin
authors.affiliation: Office of Environmental Health Hazard Assessment, 1515 Clay St, 16th Floor, Oakland, CA, USA.
authors.forename: Rupa
authors.initials: R
authors.lastname: Basu
authors.affiliation: University of California, Davis, CA, USA.
authors.forename: Ellen B
authors.initials: EB
authors.lastname: Gold
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Joyce T
authors.initials: JT
authors.lastname: Bromberger
authors.affiliation: Albert Einstein College of Medicine, New York, NY, USA.
authors.forename: Carol
authors.initials: C
authors.lastname: Derby
authors.affiliation: Rush University Medical Center, Chicago, IL, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Feinstein
authors.affiliation: Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: Gail A
authors.initials: GA
authors.lastname: Greendale
authors.affiliation: University of Michigan Hospital and Health Systems, Ann Arbor, MI, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Jackson
authors.affiliation: Rush University Medical Center, Chicago, IL, USA.
authors.forename: Howard M
authors.initials: HM
authors.lastname: Kravitz
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Karen A
authors.initials: KA
authors.lastname: Matthews
authors.affiliation: Kaiser Permanente, Oakland, CA, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Sternfeld
authors.affiliation: School of Public Health, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Tomey
authors.affiliation: Albert Einstein College of Medicine, Yeshiva University, Jersey City, NJ, USA.
authors.forename: Robin R
authors.initials: RR
authors.lastname: Green
authors.affiliation: Office of Environmental Health Hazard Assessment, 1515 Clay St, 16th Floor, Oakland, CA, USA.
authors.forename: Rochelle
authors.initials: R
authors.lastname: Green
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008593:Menopause / Q000097:blood*; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects*; D014481:United States / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D052638:Particulate Matter; D002097:C-Reactive Protein
keywords: Air pollution; C-reactive protein; Cardiovascular diseases; PM2.5; Susceptibility