Exposure to welding fumes increases lung cancer risk among light smokers but not among heavy smokers: evidence from two case-control studies in Montreal.

Eric Vallières (1) , Javier Pintos (1) , Jérôme Lavoué (1) , Marie-Élise Parent (2) , Bernard Rachet (3) , Jack Siemiatycki (1, 4, 5)

1 CHUM - Centre Hospitalier de l'Université de Montréal
2 INRS-IAF - Institut Armand Frappier
3 LSHTM - London School of Hygiene and Tropical Medicine
4 Department of Social and Preventive Medicine
5 Guzzo-Cancer Research Society Chair in Environment and Cancer, School of Public Health

We investigated relationships between occupational exposure to gas and arc welding fumes and the risk of lung cancer among workers exposed to these agents throughout the spectrum of industries. Two population-based case-control studies were conducted in Montreal. Study I (1979-1986) included 857 cases and 1066 controls, and Study II (1996-2001) comprised 736 cases and 894 controls. Detailed job histories were obtained by interview and evaluated by an expert team of chemist-hygienists to estimate degree of exposure to approximately 300 substances for each job. Gas and arc welding fumes were among the agents evaluated. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) of lung cancer using logistic regression, adjusting for smoking history and other covariates. The two studies provided similar results, so a pooled analysis was conducted. Among all subjects, no significant association was found between lung cancer and gas welding fumes (OR = 1.1; 95% CI = 0.9-1.4) or arc welding fumes (OR = 1.0; 95% CI = 0.8-1.2). However, when restricting attention to light smokers, there was an increased risk of lung cancer in relation to gas welding fumes (OR = 2.9; 95% CI = 1.7-4.8) and arc welding fumes (OR = 2.3; 95% CI = 1.3-3.8), with even higher OR estimates among workers with the highest cumulative exposures. In conclusion, there was no detectable excess risk of lung cancer due to welding fumes among moderate to heavy smokers; but among light smokers we found an excess risk related to both types of welding fumes.

Domaines: Maladies infectieuses

Eric Vallières, Javier Pintos, Jérôme Lavoué, Marie-Élise Parent, Bernard Rachet, et al.. Exposure to welding fumes increases lung cancer risk among light smokers but not among heavy smokers: evidence from two case-control studies in Montreal.. Nutrition and Cancer, 2012, 1 (1), pp.47-58. ⟨10.1002/cam4.6⟩. ⟨pasteur-01009237⟩