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.