PLEURAL MESOTHELIOMA - DOSE-RESPONSE RELATION AT LOW-LEVELS OF ASBESTOS EXPOSURE IN A FRENCH POPULATION-BASED CASE-CONTROL STUDY

A hospital-based case-control study of the association between past oc cupational exposure to asbestos and pleural mesothelioma was carried o ut in five regions of France. Between 1987 and 1993, 405 cases and 387 controls were interviewed. The job histories of these subjects were e valuated by a group of experts for exposure to asbestos fibers accordi ng to probability, intensity, and frequency. A cumulative exposure ind ex was calculated as the product of these three parameters and the dur ation of the exposed job, summed over the entire working life. Among m en, the odds ratio increased with the probability of exposure and was 1,2 (95% confidence interval (CI) 0.8-1.9) for possible exposure and 3 .6 (95% CI 2.4-5.3) for definite exposure. A dose-response relation wa s observed with the cumulative exposure index: The odds ratio increase d from 1.2 (95% CI 0.8-1.8) for the lowest exposure category to 8.7 (9 5% CI 4.1-18.5) for the highest. Among women, the odds ratio for possi ble or definite exposure was 18,8 (95% CI 4.1-86.2). We found a clear dose-response relation between cumulative asbestos exposure and pleura l mesothelioma in a population-based case-control study with retrospec tive assessment of exposure. A significant excess of mesothelioma was observed for levels of cumulative exposure that were probably far belo w the limits adopted in most industrial countries during the 1980s.