Lung cancer mortality among asbestos textile workers: a review and update.

In an update of the mortality of the cohort of 1200 South Carolina textile workers, of whom almost half died, there were 185 excess deaths (SMR = 1.44), which included 71 cardiovascular diseases (SMR = 1.37), 43 non-malignant respiratory diseases (SMR = 2.25) and 41 lung cancers (SMR = 2.25). Only two definite mesotheliomas were observed. Other possible cases may have occurred but no confirmatory pathology was available. Strong exposure-response relationships have been found for lung cancer and for non-malignant respiratory diseases. The data suggest a doubling of the lung cancer risk at an exposure of approximately 30 fibre years. Mortality from pneumoconiosis and other respiratory diseases was elevated at even the lowest cumulative exposure category (< 2 f ml-1 years). A nested case-control analysis failed to demonstrate a significant role for mineral oil exposure in the etiology of lung cancer. Differences in airborne fibre sizes may be important in explaining different lung cancer and pneumoconiosis risks in various industries. In particular, the data on airborne fibres in textile manufacturing industries suggested 11-27% were longer than 5 microns compared to 2-5% for mining and milling.