Associations between occupational exposure to benzene, toluene and xylene and risk of lung cancer in Montreal

Background Benzene, toluene and xylene (BTX) are aromatic hydrocarbons with inconclusive evidence of lung carcinogenicity. The aim of this research was to assess the associations between occupational exposures to BTX agents and lung cancer. Methods In a population-based case-control study of lung cancer, occupational histories were obtained and exposures were assessed by experts. Unconditional multivariate logistic regression was used to estimate ORs and 95% CIs, among men, between various metrics of occupational exposure to BTX and lung cancer, while adjusting for established and possible risk factors. Results Considerable overlap was found between occupational exposure to BTX, where the majority of exposed participants were exposed to all three chemicals. Lung cancer was associated with exposure to benzene (OR=1.35; 95%CI 0.99 to 1.84), toluene (OR=1.31; 95%CI 0.99 to 1.74) and xylene (OR=1.44; 95%CI 1.03 to 2.01). While these results were adjusted for smoking and other recognised and possible lung cancer risk factors, they were not mutually adjusted among the three BTX agents. Conclusions Our study provides suggestive evidence that occupational exposure to one or more of the BTX agents may be associated with lung cancer.