Past Asbestos Exposure in Rolling Stock Manufacturing in the Absence of Environmental Monitoring: An Original Method.

OBJECTIVE: The aim of this study is the reconstruction of asbestos exposure in absence of environmental monitoring data, to use the results in a cohort study of railway rolling stock workers. METHODS: To reconstruct past exposures, the production data (number of rolling stock and asbestos content) and working methods were reconstructed with former employees and company documentation, literature data, and author expertise. RESULTS: The result of the work is a job/exposure matrix from 1956 to 1979, when sprayed asbestos was used as insulator of the metal bodies. Annual exposure estimate varies from 0.08 to 4.9 fb/mL depending on the specific jobs. Thirty-one mesotheliomas with occupational exposure, one with environmental and one with family exposures, were identified. CONCLUSIONS: The originality of the study consists on the use of company production data to establish frequency duration of asbestos exposure.

Prediction of mesothelioma and lung cancer in a cohort of asbestos exposed workers.

BACKGROUND: Several papers have reported state-wide projections of mesothelioma deaths, but few have computed these predictions in selected exposed groups. OBJECTIVE: To predict the future deaths attributable to asbestos in a cohort of railway rolling stock workers. METHODS: The future mortality of the 1,146 living workers has been computed in term of individual probability of dying for three different risks: baseline mortality, lung cancer excess, mesothelioma mortality. Lung cancer mortality attributable to asbestos was calculated assuming the excess risk as stable or with a decrease after a period of time since first exposure. Mesothelioma mortality was based on cumulative exposure and time since first exposure, with the inclusion of a term for clearance of asbestos fibres from the lung. RESULTS: The most likely range of the number of deaths attributable to asbestos in the period 2005-2050 was 15-30 for excess of lung cancer, and 23-35 for mesothelioma. CONCLUSION: This study provides predictions of asbestos-related mortality even in a selected cohort of exposed subjects, using previous knowledge about exposure-response relationship. The inclusion of individual information in the projection model helps reduce misclassification and improves the results. The method could be extended in other selected cohorts.