We used data from the ICARE study, a French population-based case-control study, to investigate the associations between welding and the risk of head and cancer.Methods
The analysis was restricted to men and included 1857 cases of squamous cell carcinomas of the oral cavity, pharynx and larynx and 2780 controls, with detailed information on lifetime occupational history, tobacco smoking and alcohol drinking. A supplementary questionnaire was used to describe welding activities for those welding more than 5% of their working time. Odds-ratios (OR) and 95% confidence intervals (CI) associated with regular and occasional welding were estimated with logistic regression, with adjustment for age, residence area, smoking, alcohol drinking and asbestos exposure.Results
Regular welding was associated with an increased risk of cancer of the larynx (OR=2.68, CI=1.52–4.75), oral cavity (OR=2.30, CI=1.17–4.53) and hypopharynx (OR=1.66, CI=0.83–3.30). No association was found with oropharyngeal cancer (OR=1.05, CI=0.57–1.95). For laryngeal cancer, the OR increased for longer duration of welding (for >10 years: OR=3.13, CI=1.42–6.90). No relationship with duration was observed for the other cancer sites. Preliminary analyses did not reveal marked differences according to the type of metal welded or to welding processes. Occasional welding for more than 10 years was associated with a slight, non-significant elevated risk of oral, laryngeal and hypopharyngeal cancer.Conclusion
Our findings suggest that welding may increase the risk of laryngeal cancer. The evidence is weaker for oral and hypopharyngeal cancer, and we found no evidence of an association with oropharyngeal cancer.