title: Association between fine particulate matter exposure and subclinical atherosclerosis: A meta-analysis.
abstract: BACKGROUND
  Epidemiological studies in humans that have evaluated the association between fine particulate matter (PM2.5) and atherosclerosis have yielded mixed results.
  
  
  METHODS
  In order to further investigate this relationship, we conducted a comprehensive search for studies published through May 2014 and performed a meta-analysis of all available observational studies that investigated the association between PM2.5 and three noninvasive measures of clinical and subclinical atherosclerosis: carotid intima media thickness, arterial calcification, and ankle-brachial index.
  
  
  RESULTS
  Five reviewers selected studies based on predefined inclusion criteria. Pooled mean change estimates and 95% confidence intervals were calculated using random-effects models. Assessment of between-study heterogeneity was performed where the number of studies was adequate. Our pooled sample included 11,947 subjects for carotid intima media thickness estimates, 10,750 for arterial calcification estimates, and 6497 for ankle-brachial index estimates. Per 10 µg/m(3) increase in PM2.5 exposure, carotid intima media thickness increased by 22.52 µm but this did not reach statistical significance (p = 0.06). We did not find similar associations for arterial calcification (p = 0.44) or ankle-brachial index (p = 0.85).
  
  
  CONCLUSIONS
  Our meta-analysis supports a relationship between PM2.5 and subclinical atherosclerosis measured by carotid intima media thickness. We did not find a similar relationship between PM2.5 and arterial calcification or ankle-brachial index, although the number of studies was small.
authors.affiliation: Master of Public Health Program, School of Public Health, Harvard University, Boston, USA.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Akintoye
authors.affiliation: Department of Environmental Health - Exposure, Epidemiology and Risk Program, School of Public Health, Harvard University, Boston, USA.
authors.forename: Liuhua
authors.initials: L
authors.lastname: Shi
authors.affiliation: Master of Public Health Program, School of Public Health, Harvard University, Boston, USA.
authors.forename: Itegbemie
authors.initials: I
authors.lastname: Obaitan
authors.affiliation: Master of Public Health Program, School of Public Health, Harvard University, Boston, USA.
authors.forename: Mayowa
authors.initials: M
authors.lastname: Olusunmade
authors.affiliation: Department of Environmental Health - Exposure, Epidemiology and Risk Program, School of Public Health, Harvard University, Boston, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Leon H Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Newman
authors.affiliation: Leon H Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, USA John.Dodson@nyumc.org.
authors.forename: John A
authors.initials: JA
authors.lastname: Dodson
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects*; D055109:Ankle Brachial Index; D058070:Asymptomatic Diseases; D050197:Atherosclerosis / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology; D002340:Carotid Artery Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology; D059168:Carotid Intima-Media Thickness; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects; D064887:Observational Studies as Topic; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects*; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D061205:Vascular Calcification / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: Particulate matter; air pollution; ankle-brachial index; tunica intima; vascular calcification