Background Evidence that painters may be at risk for lung cancer comes mainly from analyses on job titles rather than on specific exposures found in the environments of painters.

Methods In the context of two large population-based case–control studies of lung cancer carried out in Montreal, we were able to assess possible relationships between lung cancer and the occupation of painter as well as exposure to paints, varnishes and stains. Interviews for study I were conducted in 1979–1986 (857 cases, 533 population controls, 1349 cancer controls) and interviews for study II were conducted in 1996–2001 (765 cases and 899 controls). Detailed lifetime job histories were elicited; a team of hygienists and chemists evaluated the evidence of exposure to many occupational substances including paint-related substances. The relative risk of lung cancer was estimated, adjusting for several potential confounders, including smoking, in a three-variable parameterisation.

Results In analyses pooling the two studies, painters had an OR of lung cancer of 1.3 (95% CI 0.9 to 2.2). Regarding exposures, ORs were: for wood varnishes and stains, 1.6 (95% CI 1.0 to 2.3); for wood and gypsum paints, 1.3 (95% CI 0.9 to 1.7); and for metal coatings, 1.1 (95% CI 0.8 to 1.6). Small numbers hampered evaluation of dose–response relationships.

Conclusions While our results cannot exclude chance or residual confounding by smoking or concomitant occupational exposures, they provide further evidence that some exposures in paint-related occupations, most notably wood varnishes and stains, increase the risk of lung cancer.