Objectives: To analyze cancer mortality in a cohort of mercury miners. Methods: Cancer mortality in 3,998 workers exposed to mercury in Minas de Almadén y Arrayanes S.A. was studied. The follow-up period was from 1895 to 1994. Vital status and the basic cause of death, in the case of fatalities, were determined. Standardized mortality ratios (SMR) by age, sex and calendar period were calculated. Expected deaths were obtained from age, sex and calendar period specific rates for the Spanish population. Results: The vital status of 92% of the workers could be assessed. At the end of the follow-up period, 1,786 workers were alive in 1994 (49%), 1,535 were dead (42%) and the status of 327 could not be determined (8%). Cancer mortality was significantly lower than expected, with an SMR of 0.72 (95% confidence interval, 0.63-0.82), mainly due to lower than expected mortality from colon and bladder cancer. Deaths from liver cancer were slightly higher than expected (20 deaths vs. 17 expected). Deaths from lung and central nervous system cancers were as expected, while mortality from kidney cancer was lower than expected. A positive trend in mortality from all types of cancer was observed, associated with exposure duration. Conclusions: This study provides additional evidence of the absence of an increased risk of cancer in workers exposed to inorganic mercury.

Objetivos: Analizar la mortalidad por cáncer en una cohorte de mineros del mercurio. Métodos: Estudiamos la mortalidad por cáncer de 3.998 mineros expuestos a mercurio de Minas de Almadén y Arrayanes, S.A. El período de seguimiento comprendió desde 1895 hasta 1994. Se determinó el estado vital y la causa básica de defunción. Se calcularon las razones de mortalidad estandarizadas (RME) según la edad, el sexo y el período de calendario. Las muertes esperadas se obtuvieron de las tasas específicas españolas. Resultados: Se determinó el estado vital del 92% de los trabajadores: 1.786 estaban vivos en 1994 (49%), 1.535 habían muerto (42%) y de 327 no pudo conocerse el estado vital (8%). La mortalidad por cáncer fue significativamente menor de la esperada (RME de 0,72; intervalo de confianza del 95%, 0,63-0,82), y se encontró el déficit principalmente en los cánceres de colon y vejiga. Se encontró un pequeño exceso en la mortalidad por cáncer de hígado, para el que se registraron 20 muertes, mientras se esperaban 17. La mortalidad por cáncer de pulmón y del sistema nervioso central fue prácticamente igual a la esperada; la mortalidad por cáncer de riñón fue menor de la esperada. Se observó una tendencia positiva en la mortalidad por todos los tipos de cáncer con la duración de la exposición. Conclusiones: Esta investigación aporta evidencias adicionales de la ausencia de un aumento sustancial del riesgo de cáncer en los trabajadores expuestos al mercurio inorgánico.

Objectives: To analyze cancer mortality in a cohort of mercury miners. Methods: Cancer mortality in 3,998 workers exposed to mercury in Minas de Almadén y Arrayanes S.A. was studied. The follow-up period was from 1895 to 1994. Vital status and the basic cause of death, in the case of fatalities, were determined. Standardized mortality ratios (SMR) by age, sex and calendar period were calculated. Expected deaths were obtained from age, sex and calendar period specific rates for the Spanish population. Results: The vital status of 92% of the workers could be assessed. At the end of the follow-up period, 1,786 workers were alive in 1994 (49%), 1,535 were dead (42%) and the status of 327 could not be determined (8%). Cancer mortality was significantly lower than expected, with an SMR of 0.72 (95% confidence interval, 0.63-0.82), mainly due to lower than expected mortality from colon and bladder cancer. Deaths from liver cancer were slightly higher than expected (20 deaths vs. 17 expected). Deaths from lung and central nervous system cancers were as expected, while mortality from kidney cancer was lower than expected. A positive trend in mortality from all types of cancer was observed, associated with exposure duration. Conclusions: This study provides additional evidence of the absence of an increased risk of cancer in workers exposed to inorganic mercury.

Objetivos: Analizar la mortalidad por cáncer en una cohorte de mineros del mercurio. Métodos: Estudiamos la mortalidad por cáncer de 3.998 mineros expuestos a mercurio de Minas de Almadén y Arrayanes, S.A. El período de seguimiento comprendió desde 1895 hasta 1994. Se determinó el estado vital y la causa básica de defunción. Se calcularon las razones de mortalidad estandarizadas (RME) según la edad, el sexo y el período de calendario. Las muertes esperadas se obtuvieron de las tasas específicas españolas. Resultados: Se determinó el estado vital del 92% de los trabajadores: 1.786 estaban vivos en 1994 (49%), 1.535 habían muerto (42%) y de 327 no pudo conocerse el estado vital (8%). La mortalidad por cáncer fue significativamente menor de la esperada (RME de 0,72; intervalo de confianza del 95%, 0,63-0,82), y se encontró el déficit principalmente en los cánceres de colon y vejiga. Se encontró un pequeño exceso en la mortalidad por cáncer de hígado, para el que se registraron 20 muertes, mientras se esperaban 17. La mortalidad por cáncer de pulmón y del sistema nervioso central fue prácticamente igual a la esperada; la mortalidad por cáncer de riñón fue menor de la esperada. Se observó una tendencia positiva en la mortalidad por todos los tipos de cáncer con la duración de la exposición. Conclusiones: Esta investigación aporta evidencias adicionales de la ausencia de un aumento sustancial del riesgo de cáncer en los trabajadores expuestos al mercurio inorgánico.

INTRODUÇÃO: Cerca de 90% dos casos de câncer de pulmão no mundo são atribuíveis ao tabagismo, porém menos de 20% dos fumantes desenvolvem câncer de pulmão. Fatores como dieta, doenças pulmonares crônicas, ocupação e, possivelmente, exposições ambientais também têm papel na etiologia desse câncer. Os fatores genéticos parecem influir na ocorrência da doença, mas as características que influenciam a suscetibilidade à neoplasia pulmonar não são precisamente conhecidas, obscurecidas pela forte influência dos fatores ambientais na determinação da doença, particularmente o tabagismo. OBJETIVOS: Estimar o efeito da ocorrência de câncer em parentes de primeiro grau no risco de câncer de pulmão. TIPO DE ESTUDO: Estudo caso-controle de base hospitalar. LOCAL: Região Metropolitana de São Paulo. PARTICIPANTES: 334 casos de neoplasia pulmonar e 578 controles emparelhados por hospital. VARIÁVEIS ESTUDADAS: Casos e controles foram entrevistados com respeito ao passado de neoplasias em parentes de primeiro grau, tabagismo, tabagismo passivo, ocupação, migração e status socioeconômico. Utilizou-se a regressão logística não-condicional para calcular o risco de câncer em familiares, o efeito conjunto de câncer em familiares e uso de tabaco, e para controlar potenciais variáveis de confusão. RESULTADOS: O odds ratio (OR) ajustado revelou um discreto excesso de risco para câncer de pulmão, não estatisticamente significante, entre os indivíduos com história de câncer de pulmão na família (OR 1,21; intervalo de confiança de 95% [IC 95%] 0,50 -- 2,92) ou entre aqueles com história de outros cânceres relacionados ao tabaco na família (OR 1,36; IC 95% 0,87 --2,14). Foi observado um efeito dose-resposta positivo para o risco de câncer de pulmão de acordo com o aumento do consumo de cigarros. Detectou-se uma interação entre as variáveis câncer na família e tabagismo. CONCLUSÕES: Observou-se um discreto aumento do risco de câncer de pulmão entre indivíduos com história positiva na família de câncer de pulmão e outros cânceres relacionados ao tabaco. Esses resultados sugerem que a presença de aglomerados de câncer na família pode ser considerada como um marcador de suscetibilidade e aumenta o risco de câncer de pulmão entre os fumantes. A interação detectada entre as variáveis agregadas de câncer na família e tabagismo no risco de câncer de pulmão é uma contribuição no conhecimento dos mecanismos da carcinogênese e poderá orientar futuras pesquisas no campo da genética do câncer.

CONTEXT: Around 90% of lung cancer worldwide is attributable to cigarette smoking, although less than 20% of cigarette smokers develop lung cancer. Other factors such as diet, chronic lung diseases, occupation and possibly environmental agents also contribute to this cancer. Genetic factors seem to play a role in lung cancer, but the precise characteristics influencing lung cancer susceptibility are not known, since genetic factors are easily obscured by the strong environmental determinants of lung cancer, particularly smoking. OBJECTIVE: To estimate the effect that cancer occurrence among first-degree relatives has on the risk of lung cancer. DESIGN: Hospital-based case-control study. SETTING: The metropolitan region of São Paulo, Brazil. PARTICIPANTS: 334 incident lung cancer cases and 578 controls matched by hospitals. MAIN MEASUREMENTS: By means of a structured questionnaire, cases and controls were interviewed about cancer occurrence in first-degree relatives, tobacco smoking, exposure to passive smoking, occupation, migration and socioeconomic status. Non-conditional logistic regression was used to calculate the risk of familial cancer aggregation, the effect of cancer in first-degree relatives and smoking in conjunction, and for controlling confounders. RESULTS: The adjusted odds ratio (OR) revealed a slight, but not statistically significant, excess risk of lung cancer for subjects with a history of lung cancer in relatives (OR 1.21; 95% confidence interval [CI] 0.50 -- 2.92). The same was found among those with a history of other tobacco-related cancers in relatives (OR 1.36; 95% CI 0.87 -- 2.14). A step gradient effect was observed regarding lung cancer risk, in accordance with increases in the number of pack-years of cigarette consumption. An interaction between familial cancer aggregation and tobacco smoking was detected. CONCLUSIONS: A mildly elevated risk of lung cancer among persons with a positive history of lung and other tobacco-related cancers was observed. The finding of an interaction between the variables of familial cancer aggregation and smoking suggests that familial cancer aggregation could be considered as a marker of susceptibility, increasing the risk of lung cancer among smokers. These results improve our knowledge of lung carcinogenesis and can guide future cancer genetic studies.