Occupational risk for laryngeal cancer

No município de São Paulo, em 1970 foram relatados 169 casos novos de câncer de laringe, com uma taxa de incidência ajustada por idade pela população mundial de 25,5/100.000 (30-74 anos) e 299 casos em 1985, elevando a taxa para 37,6 (ambos nosexo masculino). O Tabagismo e o consumo de álcool são os fatores de risco mais bem estabelecidos para o câncer de laringe. Com relação aos fatores ocupacionais, o único carcinógeno estabelecido é a exposição à névoa de ácidos inorgânicosfortes. É proposto um estudo caso-controle de base hospitalar, para investigar e quantificar o papel da exposição ocupacional no desenvolvimento do câncer de laringe e é discutida uma nova proposta de avaliação de exposição que visa melhorar avalidade interna desse tipo de estudoLaryngeal cancer comprises 3,1% of the new cases of cancer in men in the world, representing the tenth most common malign neoplasm for males. In São Paulo City, 169 new cases of laryngeal cancer were reported in 1970, representing 25,5/100.000 and 299 cases in 1985, increasing the rate to 37,6/100.000 (both for males, age standardized truncated rate, 30-74 years). The best established risk factors for laryngeal cancer are tobacco and alcohol. In respect to occupational factors, the only established carcinogen is exposure to strong inorganic acid mists. However, asbestos, pesticides, paints, gasoline and diesel engine emissions, dusts, among other factors are reported in the literature as occupational agents that increase the risk of laryngeal cancer. A hospital-based case-control study was conducted, in seven hospitals in São Paulo, to investigate occupational risk factors for laryngeal cancer. The study included 122 laryngeal cancers and 187 controls, selected by frequency matching on sex and age. Detailed information on smoking, alcohol consumption, and occupational history was collected. Occupational hygienists assessed the exposure to 49 agents. Odds Ratios (OR) and 95% confidence intervals (95% CI) were estimated by unconditional logistic regression, and were adjusted for sex, age, smoking and alcohol. Laryngeal cancer was associated with exposure to respirable free crystalline silica (OR 1,83, 95% CI 1,00 - 3,36), soot (from coal, coke, fuel oil, wood) (OR 1,78, 95% CI 1,03 - 3,03), fumes (OR 2,55, CI 95% 1,14 - 5,67) and to live animals (OR 1,80, 95% CI 1,02 - 3,19). This study showed that occupational exposures to: respirable free crystalline silica, soot (from coal, coke, fuel oil, wood), fumes and live animals are risk factors for laryngeal cancer