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

Abstract

BackgroundPrevious 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).MethodsIn 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.ResultsThirty-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.ConclusionsOur 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1301-2) contains supplementary material, which is available to authorized users.

Epidemiology of malignant mesothelioma in Italy: surveillance systems, territorial clusters and occupations involved

“…The geographical distribution of MM cases is a sort of map of the industrial use of asbestos before the ban in 1992. The figures reported here and in previous papers (22,30) demonstrate how a higher than expected incidence (and mortality) in mesotheliomas has been observed in areas with direct use of asbestos as the naval shipyards, asbestos-cement plants and other industrial activities, such as railways carriages maintenances. In the interpretation of territorial maps, it is necessary to consider the possible source of bias due to the municipality of residence at the time of diagnosis taken as a proxy for exposure place.…”

“…The forecast scenarios for MM epidemic curve has been estimated according to a model including asbestos consumption before the ban (21), indicating the period of peak in mesothelioma mortality around 2015-2020. The territorial clustering of incident cases has been identified and discussed, based on collected cases and asbestos exposure qualitative assessment provided by CORs (22). The characteristics, and the extent of non-occupational exposure (above all environmental and familial modalities of exposure), have been estimated around 10% of cases (23) mainly due to the residence near asbestos cement plants and to the cohabitation with occupationally exposed subjects.…”

Occupational diseases in Italian national priority contaminated sites

“…Regarding the geographical distribution of occupational diseases in the NPCSs, a significant excess was observed in all four territorial macro‐areas (North‐West, North‐East, Centre and South and Isles). In the North‐West, the sites of Casale Monferrato, Pitelli, and Broni show the highest excesses of occupational diseases (more than 30 observed cases and SIR higher than 200), clearly due to the presence of industrial activities with recognized direct or indirect asbestos use in the past . Accordingly, malignant mesothelioma, lung cancer, and other diseases of the respiratory system represented the great part of occupational compensated cases in these sites.…”

Non-neoplastic asbestos-related respiratory diseases: what relationship with other lung diseases?

“…In Italy, asbestos production reached a peak in the period between 1976-1980, but remained steady over 100,000 tons/ year until 1987. These temporal patterns delayed the peak in asbestos consumption in Italy compared to other European countries and in the United States [1]. Moreover, the use of asbestos continues to increase in Asia.…”