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105 Pooled analysis of two case-control studies of polycyclic aromatic hydrocarbons and risk of lung cancer
  1. F Momoli1,
  2. Pintos2,
  3. Parent3,
  4. Richardson2,
  5. Krewski4,
  6. Siemiatycki2
  1. 1Ottawa Hospital Research Institute, Ottawa, Canada
  2. 2Centre de Recherche du CHUM, Université de Montréal, Montreal, Canada
  3. 3Institut Armand-Frappier, Montreal, Canada
  4. 4University of Ottawa, Ottawa, Canada


PAHs are ubiquitous compounds formed during incomplete combustion of organic material. IARC recently classified benzo (a)pyrene and several occupational circumstances involving PAH exposure as carcinogenic, though human evidence remains limited.

Objectives To examine the effects of occupational exposure to PAHs arising from different combustion products on risk of lung cancer.

Methods Data was provided from two case-control studies conducted in Montreal. Study 1 (1979–1986) included 857 men with lung cancer, 533 controls from electoral lists, and 1346 controls with other cancers. Study 2 (1996–2001) included 738 men with lung cancer and 899 controls selected from the electoral list. Occupational histories were obtained and lifetime chemical exposure was derived by hygienists for benzo (a)pyrene and profiles of PAHs, according to source (wood, petroleum, coal, or other, which included rubber, plastic, and food). Data were pooled across studies.

Results Prevalence of any PAH was 68% in the Study 1 population and 55% in Study 2. Adjusting for confounding due to smoking and common demographics, exposure to any PAH resulted in an odds ratio of 1.14 (95% CI of 0.95–1.35) compared to individuals unexposed to PAHs; results were similar at substantial levels of exposure. Considering workers exposed to only a single profile of PAH depending on the combustion product, results were: PAH from wood [0.88 (0.35–2.21)], from coal [0.96 (0.52–1.78)], from petroleum [1.04 (0.86–1.25)], and from other sources [1.84 (1.04–3.25)]. Exposure to benzo (a)pyrene resulted in an odds ratio of 1.31 (1.06–1.63).

Conclusions Results suggested excess risk associated with exposure to benzo (a)pyrene and to PAHs arising from cooking fumes, plastic, and rubber; but not for PAH exposures derived from wood, coal, and petroleum combustion products. These results are partly in line with previous reports of highly exposed workers, though exposure levels would not have been as high in our population-based study.

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