Epidemiological patterns of asbestos exposure and spatial clusters of incident cases of malignant mesothelioma from the Italian national registry

Abstract BACKGROUND: Previous ecological spatial studies of malignant mesothelioma cases, mostly based on mortality data, lack reliable data on individual exposure to asbestos, thus failing to assess the contribution of different occupational and environmental sources in the determination of risk excess in specific areas. This study aims to identify territorial clusters of malignant mesothelioma through a Bayesian spatial analysis and to characterize them by the integrated use of asbestos exposure information retrieved from the Italian national mesothelioma registry (ReNaM). METHODS: In the period 1993 to 2008, 15,322 incident cases of all-site malignant mesothelioma were recorded and 11,852 occupational, residential and familial histories were obtained by individual interviews. Observed cases were assigned to the municipality of residence at the time of diagnosis and compared to those expected based on the age-specific rates of the respective geographical area. A spatial cluster analysis was performed for each area applying a Bayesian hierarchical model. Information about modalities and economic sectors of asbestos exposure was analyzed for each cluster. RESULTS: Thirty-two clusters of malignant mesothelioma were identified and characterized using the exposure data. Asbestos cement manufacturing industries and shipbuilding and repair facilities represented the main sources of asbestos exposure, but a major contribution to asbestos exposure was also provided by sectors with no direct use of asbestos, such as non-asbestos textile industries, metal engineering and construction. A high proportion of cases with environmental exposure was found in clusters where asbestos cement plants were located or a natural source of asbestos (or asbestos-like) fibers was identifiable. Differences in type and sources of exposure can also explain the varying percentage of cases occurring in women among clusters. CONCLUSIONS: Our study demonstrates shared exposure patterns in territorial clusters of malignant mesothelioma due to single or multiple industrial sources, with major implications for public health policies, health surveillance, compensation procedures and site remediation programs

Epidemiologic surveillance of mesothelioma for the prevention of asbestos exposure also in non-traditional settings

OBJECTIVE: to show how malignant mesothelioma (MM) surveillance not only identifies settings of exposure representing past industrial history, but it may also detect conditions of current exposure relevant for the prevention, if the wide spectrum of asbestos uses is considered. DESIGN: active search of MM cases and exposure assessment at individual level through a questionnaire; identification of exposure circumstances relevant for prevention. SETTING AND PARTICIPANTS: Italy, all the Regions where a Regional Operating Centre (COR) is established to identify all MM cases diagnosed in the population and analyze their occupational, residential, household and environmental histories. Period of diagnosis: 1993-2008. MAIN OUTCOME MEASURES: descriptive analysis of MM cases and of asbestos exposures. RESULTS: ReNaM includes 15,845 cases of MM diagnosed between 1993 and 2008. The male/female ratio is 2.5. Mean age at diagnosis is 69 years. Pleural MMs represent 93% of all cases. Exposures have been investigated in 12,065 cases (76%). The median latency time is 46 years. In addition to clusters of MM cases in activities well known to entail asbestos use, different current exposure circum-stances requiring intervention have been evidenced. CONCLUSIONS: on the basis of this experience, epidemiological surveillance of all occupational cancers should be implemented to foster synergies with the compensation system and the Local Health Authorities' occupational safety and health services, as required by the Italian Legislative Decree N. 81/2008