title: Estimating exposures in the asphalt industry for an international epidemiological cohort study of cancer risk.
abstract: BACKGROUND
  An exposure matrix (EM) for known and suspected carcinogens was required for a multicenter international cohort study of cancer risk and bitumen among asphalt workers.
  
  
  METHODS
  Production characteristics in companies enrolled in the study were ascertained through use of a company questionnaire (CQ). Exposures to coal tar, bitumen fume, organic vapor, polycyclic aromatic hydrocarbons, diesel fume, silica, and asbestos were assessed semi-quantitatively using information from CQs, expert judgment, and statistical models. Exposures of road paving workers to bitumen fume, organic vapor, and benzo(a)pyrene were estimated quantitatively by applying regression models, based on monitoring data, to exposure scenarios identified by the CQs.
  
  
  RESULTS
  Exposures estimates were derived for 217 companies enrolled in the cohort, plus the Swedish asphalt paving industry in general. Most companies were engaged in road paving and asphalt mixing, but some also participated in general construction and roofing. Coal tar use was most common in Denmark and The Netherlands, but the practice is now obsolete. Quantitative estimates of exposure to bitumen fume, organic vapor, and benzo(a)pyrene for pavers, and semi-quantitative estimates of exposure to these agents among all subjects were strongly correlated. Semi-quantitative estimates of exposure to bitumen fume and coal tar exposures were only moderately correlated. EM assessed non-monotonic historical decrease in exposures to all agents assessed except silica and diesel exhaust.
  
  
  CONCLUSIONS
  We produced a data-driven EM using methodology that can be adapted for other multicenter studies.
authors.affiliation: Occupational and Environmental Health Group, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Igor
authors.initials: I
authors.lastname: Burstyn
authors.forename: Paolo
authors.initials: P
authors.lastname: Boffetta
authors.forename: Timo
authors.initials: T
authors.lastname: Kauppinen
authors.forename: Pirjo
authors.initials: P
authors.lastname: Heikkilä
authors.forename: Ole
authors.initials: O
authors.lastname: Svane
authors.forename: Timo
authors.initials: T
authors.lastname: Partanen
authors.forename: Isabelle
authors.initials: I
authors.lastname: Stücker
authors.forename: Rainer
authors.initials: R
authors.lastname: Frentzel-Beyme
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Ahrens
authors.forename: Hiltrud
authors.initials: H
authors.lastname: Merzenich
authors.forename: Dick
authors.initials: D
authors.lastname: Heederik
authors.forename: Mariëtte
authors.initials: M
authors.lastname: Hooiveld
authors.forename: Sverre
authors.initials: S
authors.lastname: Langård
authors.forename: Britt G
authors.initials: BG
authors.lastname: Randem
authors.forename: Bengt
authors.initials: B
authors.lastname: Järvholm
authors.forename: Ingvar
authors.initials: I
authors.lastname: Bergdahl
authors.forename: Judith
authors.initials: J
authors.lastname: Shaham
authors.forename: Joseph
authors.initials: J
authors.lastname: Ribak
authors.forename: Hans
authors.initials: H
authors.lastname: Kromhout
mesh_terms: D015331:Cohort Studies; D004812:Epidemiologic Methods; D005060:Europe / Q000453:epidemiology; D006801:Humans; D006838:Hydrocarbons; D019570:Inhalation Exposure / Q000706:statistics & numerical data*; D007557:Israel / Q000453:epidemiology; D015233:Models, Statistical; D015337:Multicenter Studies as Topic; D016273:Occupational Exposure / Q000706:statistics & numerical data*; D018570:Risk Assessment
chemical_list: D006838:Hydrocarbons; C006647:asphalt