title: Effects of exposure to air pollution on blood coagulation.
abstract: BACKGROUND
  Consistent evidence has indicated that air pollution increases the risk of cardiovascular diseases. The underlying mechanisms linking air pollutants to increased cardiovascular risk are unclear.
  
  
  OBJECTIVE
  We investigated the association between the pollution levels and changes in such global coagulation tests as the prothrombin time (PT) and the activated partial thromboplastin time (APTT) in 1218 normal subjects from the Lombardia Region, Italy. Plasma fibrinogen and naturally occurring anticoagulant proteins were also evaluated.
  
  
  METHODS
  Hourly concentrations of particulate (PM10) and gaseous pollutants (CO, NO2, SO2, and O3) were obtained from 53 monitoring sites covering the study area. Generalized additive models were applied to compute standardized regression coefficients controlled for age, gender, body mass index, smoking, alcohol, hormone use, temperature, day of the year, and long-term trends.
  
  
  RESULTS
  The PT became shorter with higher ambient air concentrations at the time of the study of PM10 (coefficient = -0.06; P < 0.05), CO (coefficient = -0.11; P < 0.001) and NO2 (coefficient =-0.06; P < 0.05). In the 30 days before blood sampling, the PT was also negatively associated with the average PM(10) (coefficient = -0.08; P < 0.05) and NO2 (coefficient = -0.08; P < 0.05). No association was found between the APTT and air pollutant levels. In addition, no consistent relations with air pollution were found for fibrinogen, antithrombin, protein C and protein S.
  
  
  CONCLUSIONS
  This investigation shows that air pollution is associated with changes in the global coagulation function, suggesting a tendency towards hypercoagulability after short-term exposure to air pollution. Whether these changes contribute to trigger cardiovascular events remains to be established.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA 02215, USA. abaccare@hsph.harvard.edu
authors.forename: A
authors.initials: A
authors.lastname: Baccarelli
authors.forename: A
authors.initials: A
authors.lastname: Zanobetti
authors.forename: I
authors.initials: I
authors.lastname: Martinelli
authors.forename: P
authors.initials: P
authors.lastname: Grillo
authors.forename: L
authors.initials: L
authors.lastname: Hou
authors.forename: S
authors.initials: S
authors.lastname: Giacomini
authors.forename: M
authors.initials: M
authors.lastname: Bonzini
authors.forename: G
authors.initials: G
authors.lastname: Lanzani
authors.forename: P M
authors.initials: PM
authors.lastname: Mannucci
authors.forename: P A
authors.initials: PA
authors.lastname: Bertazzi
authors.forename: J
authors.initials: J
authors.lastname: Schwartz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000397:Air Pollution / Q000009:adverse effects* / Q000706:statistics & numerical data; D015415:Biomarkers / Q000097:blood; D001777:Blood Coagulation; D001780:Blood Coagulation Tests; D002648:Child; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D005740:Gases / Q000032:analysis; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000032:analysis; D012044:Regression Analysis; D019851:Thrombophilia / Q000209:etiology*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D005740:Gases; D052638:Particulate Matter