LUNG CANCER AND EXPOSURE TO CHRYSOTILE AND AMPHIBOLES

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Considerable controversy surrounds the question of whether the two different ytpes of asbestos -- amphilboles and chrysotile -- have different carcinogenic potencies. The "amphibole hypothesis" holds that chrysotile is less likely to cause lung cancer and mesothelioma than are the amphiboles. The abiolity to clarify this question is limited by a lack of quantitative data with which to estimate separate dose-response curves for the two fiber types. This proposal seeks funds to study lung cancer and mesothelimoma risks in a Sovenian cement asbestos plant in which excellent historical exposure data are available, distinguishing the two broad classes of asbestos fibers. The small Grant Investigator, an occupatinal physician and epidemiology doctoral student, would conduct a detailed historical exposure reconstruction and case control studies of lung cancer and mesothelimoma. The cohort of workers employed in the cement asbestos manufacturing plant of salonit Anhovo, Slovenia will be constructed from existing detailed wage lists which date from the 1940s. Cases will be all incident cases of primary lung cancer or mesothelioma from 1964 to 1994 in those who were hired after 1959 and who worked at least one month between 1964 and 1994. They will be identified using data from the slovenian National Cancer Registry, one of the oldest national registries in Europe. Exposure measurements are available for most exposed jobs begining in 1961. Three different methods of measurement were used: konimeter measuring particles/cm3, a gravimetric method measuring milligrams/m3, and membrane filter measuring fibers/cm3. Regression analyses will be used to calculate operation-specific conversion factors among these methods. Cumulative lifetime exposure to amphilboles and to chrysotile will be estimated sparately for all cases and controls. Logistic regression models will be used to estimate separate exposure-resonse curves for the two fiber types controlling for smoking (smoking history data available on each worker from medical records).