title: Traffic-related air pollution and prostate cancer risk: a case-control study in Montreal, Canada.
abstract: OBJECTIVE
  There is a paucity of information on environmental risk factors for prostate cancer. We conducted a case-control study in Montreal to estimate associations with exposure to ground-level nitrogen dioxide (NO2), a marker for traffic-related air pollution.
  
  
  METHODS
  Cases were 803 men with incident prostate cancer, ≤75 years of age, and diagnosed across all French hospitals in Montreal. Concurrently, 969 controls were drawn from electoral lists of French-speaking individuals residing in the same electoral districts as the cases and frequency-matched by age. Concentrations of NO2 were measured across Montreal in 2005-2006. We developed a land use regression model to predict concentrations of NO2 across Montreal for 2006. These estimates were back-extrapolated to 1996. Estimates were linked to residential addresses at the time of diagnosis or interview. Unconditional logistic regression was used, adjusting for potential confounding variables.
  
  
  RESULTS
  For each increase of 5 parts per billion of NO2, as estimated from the original land use regression model in 2006, the OR5ppb adjusted for personal factors was 1.44 (95% CI 1.21 to 1.73). Adding in contextual factors attenuated the OR5ppb to 1.27 (95% CI 1.03 to 1.58). One method for back-extrapolating concentrations of NO2 to 1996 (about 10 years before the index date) gave the following OR5ppb: 1.41 (95% CI 1.24 to 1.62) when personal factors were included, and 1.30 (95% CI 1.11 to 1.52) when contextual factors were added.
  
  
  CONCLUSIONS
  Exposure to ambient concentrations of NO2 at the current address was associated with an increased risk of prostate cancer. This novel finding requires replication.
authors.affiliation: Epidemiology and Biostatistics Unit, INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, Canada. marie-elise.parent@iaf.inrs.ca
authors.forename: Marie-Élise
authors.initials: MÉ
authors.lastname: Parent
authors.forename: Mark S
authors.initials: MS
authors.lastname: Goldberg
authors.forename: Dan L
authors.initials: DL
authors.lastname: Crouse
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Ross
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Valois
authors.forename: Alexandre
authors.initials: A
authors.lastname: Liautaud
mesh_terms: D000328:Adult; D000368:Aged; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D016022:Case-Control Studies; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity*; D011471:Prostatic Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D011792:Quebec / Q000453:epidemiology; D012307:Risk Factors; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D001335:Vehicle Emissions; D009585:Nitrogen Dioxide