Occupational risk factors of laryngeal cancer

Laryngeal cancer affects mainly heavy smokers and excessive drinkers. The evidence for a causal association is strong for asbestos and strong inorganic acid mists. The relative risk of laryngeal cancer among workers exposed to asbestos is in the order of 1.2, with limited evidence of a gradient in risk according to duration or level of exposure. An association between exposure to mists of strong inorganic acids, mainly sulfuric acid, and laryngeal cancer has been reported in both cohort and case-control studies, but the quantification of the excess risk is complicated by heterogeneity in study results. Several other agents have been suggested to increase the risk of laryngeal cancer, including polycyclic aromatic hydrocarbons, wood dust, diesel engine exhaust, and organic solvents, but the evidence is weak and inconsistent. An increased risk has been reported for occupational groups with exposure to known carcinogens (e.g., cooks, waiters, plumbers), and for other groups without clear exposure to known carcinogens (e.g., shoe workers). Residual confounding by tobacco smoking and alcohol drinking, two strong risk factors of the disease, remains a concern in many available studies. In most populations, occupational exposures are likely to play a minor role in laryngeal carcinogenesis.