Sensitivity and specificity of the linkage procedure with occupational activity in asbestos production

Asbestos exposure has been deadly to many people in the past decades

. There is a mountain of important literature and research done on this area. One interesting study is called, "Mortality from lung cancer and population risk attributable to asbestos in an asbestos cement manufacturing town in Italy." By C Magnani, M Leporati - Occup Environ Med 1998;55:111-114. Here is an excerpt: "Abstract - OBJECTIVE: To estimate mortality from lung cancer and the risk attributable to asbestos separately for asbestos cement workers and for the general (non-occupationally exposed) population in the town of Casale Monferrato, where the largest Italian asbestos cement factory had been in operation in 1907-86. According to cancer registry data, in the same town the incidence of malignant mesothelioma in the general population is about 10 times higher than in comparable Italian provinces. METHOD: Decedents from lung cancer in 1989-95 were nominally identified in the list of decedents kept at the Local Health Authority of Casale Monferrato. Workers in the asbestos cement factory have been identified with a search in the nominal list of workers and the same was done for the wives of asbestos cement workers. These lists have already been used in cohort studies. Sensitivity and specificity of the linkage procedure with occupational activity in asbestos cement production have been evaluated in a previous study. Population at risk was estimated on the basis of official figures and on the results of the cohort study of asbestos cement workers. RESULTS: 227 deaths from lung cancer were included (184 men and 43 women). Among the asbestos cement workers mortalities were 234.0 x 100,000 person-years among men and 35.5 among women. Corresponding figures in the general (non-occupationally exposed) population in Casale Monferrato were 80.6 and 18.7. The rates in the general population were not higher than in the rest of the region. Attributable risk (AR) among the asbestos cement workers (and wives) is 67.5% (95% confidence interval (95% CI) 56.8 to 78.2) for men and 51.3% (95% CI 14.9 to 87.8) among women. Population AR to occupational or paraoccupational exposure in the asbestos cement production is 18.3% (95% CI 11.1 to 25.6) among men and 10.1% (95% CI 0 to 24.6) among women. CONCLUSION: This work did not show an increase in mortality from lung cancer for the population not exposed occupationally, but a large excess was found among men and women occupationally exposed in asbestos cement production. The total burden of lung cancer due to occupational exposure to asbestos may be underestimated, as only occupational exposure in asbestos cement production was taken into consideration. Nevertheless even a single factory can be responsible for a considerable proportion of deaths from lung cancer in a population."

Another interesting study is called, "Reaction of Rat Lungs to Inhaled Chrysotile Asbestos Following Acute and Subchronic Exposures" - 1983, Vol. 5, No. 1, Pages 1-21

Experimental Lung Research Here is an excerpt: "Inhalation of asbestos fibers can cause fibrotic and neoplastic diseases in the lung. The early in vivo interactions between fibers and lung tissue that initiate these diseases have received little study. Male and female Fischer 344 rats were placed in inhalation chambers and exposed to 9.06 1.83 mg/m3 (average respirable mass) of chrysotile asbestos for 1 hr, 1 day, 7 hrlday for 5 days, or 5 days/week for 3 months. Qualitative examination of the tissue showed that, after 1 day, fibers were found not only in the alveolar macrophages, but also in the epithelium and interstitium of the alveolar region. After 3 months, numerous fibers were present in the epithelium and interstitium. Morphometric analysis of this tissue showed that these compartments were also the most significantly changed as a result of asbestos exposure. The majority of epithelial changes were attributable to a 57% increase in the number of type II cells and a 90% increase in their average cell volume. The interstitial cell population increased 58% with a 40% increase in the average cell volume. There was no significant increase in the volume of noncellular interstitium. A morphologic characterization of the interstitial cells showed that interstitial macrophages accounted, for almost the entire increase in this population and that 88% of the fiber-containing cells were macrophages. Several interstitial macrophages contained membrane-bound inclusions which were shown by x-ray energy spectrometry to be microcalcifications. They were composed of rings of calcium phosphate granules around asbestos fibers. These microcalcifications may indicate sublethal cell injury caused by the presence of asbestos fibers in the cell cytoplasm."

We all owe a debt of gratitude to these fine researchers for their important work. If you found any of these excerpts helpful, please read the studies in their entirety.

Sensitivity and specificity of the linkage procedure with occupational activity in asbestos production

By: Montwrobleski77

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