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Saturday 20, November, 2004 13:30 - 15:30, No.2 Conference Room Workshop E Epidemiology and Public Health Chairs: Gunnar Hillerdal and Kohki Inai Mortality Experience in a Historical Cohort of Chrysotile Asbestos Textile Workers Carlo Mamo1 and Giuseppe Costa2 1 Epidemiology Unit, Piedmont Region, Grugliasco, Turin, Italy 2 Department of Public Health, Faculty of Medicine, University of Turin, Italy ABSTRACT: Introduction and aims The issue of whether exposure to chrysotile asbestos alone, without contamination from amphibole asbestos, causes lung cancer, mesothelioma and non malignant diseases was investigated in a historical cohort in Grugliasco, Italy, where the largest Italian asbestos textile factory had been in operation in 1900-86. Methods The study cohort comprised 1,653 asbestos textile plant workers exposed to chrysotile only. Vital status was ascertained by means of postal follow-up. The cause of death was ascertained through a record linkage with the national mortality registry. Standardized Mortality Ratios (SMR) were computed using the mortality rates of the Turin working population as a reference (in order to reduce the healthy worker effect and the confounding from social class), adjusted for age and birth area. Observation period went from 1/1/1981 to 31/12/1995. Results Overall mortality was significantly in excess, in both males (SMR=212; 119 obs.) and females (SMR=265; 84 obs.). Cancer mortality was significantly in excess (SMR=194 males; SMR=261 females). Statistically significant excesses for pleural mesothelioma (SMR=3322 males; SMR=13248 females) and lung cancer (SMR=302 males; SMR=523 females) were observed. Other sites of cancer in excess were: larynx, stomach, pancreas and brain. Mortality excesses for asbestosis (SMR=12797 males; SMR=3124 females), ischemic heart diseases (SMR=139 males; SMR=164 females) and cerebrovascular diseases (SMR=159 males; SMR=173 females) were estimated. Analysis for length of employment and year of hire evidenced a correlation between mortality rates and length of employment and the latency period for the tumours. Conclusions These results confirm that heavy exposure to pure chrysotile asbestos alone, with negligible amphibole contamination, cause lung cancer and malignant mesothelioma in exposed workers. Moreover, the results suggest, in agreement with previous studies, a role of the exposure to asbestos in the etiology of other sites of cancer (particularly larynx and stomach) and of non malignant diseases (ischemic heart diseases and cerebrovascular diseases). |