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

Our plain-English summary of Epidemiological patterns of asbestos exposure and spatial clusters of incident cases of malignant mesothelioma from the Italian national registry, by M. Corfiati, A. Scarselli, A. Binazzi, et al (BMC Cancer, 2015).

The study

• Authors: M. Corfiati, A. Scarselli, A. Binazzi, D. Di Marzio, M. Verardo, D. Mirabelli, V. Gennaro, C. Mensi, G. Schallemberg, E. Merler, C. Negro, A. Romanelli, E. Chellini, S. Silvestri, M. Cocchioni, C. Pascucci, F. Stracci, E. Romeo, L. Trafficante, I. Angelillo, S. Menegozzo, M. Musti, D. Cavone, G. Cauzillo, F. Tallarigo, R. Tumino, M. Melis, S. Iavicoli, A. Marinaccio, ReNaM Working Group
• Journal: BMC Cancer
• Published: 2015;15:286
• Cited by: 39 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

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.

In plain English

Using Italy's national mesothelioma registry (ReNaM), the authors looked for geographic clusters of malignant mesothelioma and described asbestos exposure within them. They analyzed 15,322 new cases at all body sites diagnosed in 1993–2008. Each case was placed in the municipality where the person lived at diagnosis, and a Bayesian statistical model was used to find groups of municipalities with raised risk. Exposure histories came from interviews for 11,852 cases. Among those interviewed, asbestos exposure was ascertained in 86.4% of men and 60.3% of women. The authors identified 32 clusters, 11 in the Northwest and 6 in the Northeast. Asbestos cement plants and shipyards were the main exposure sources. Sectors not using asbestos directly, such as non-asbestos textiles, metal engineering and construction, also contributed. More than 15% of cases were attributed to environmental exposure in the Casale Monferrato, Bari and Broni clusters, which centered on asbestos cement industry. The authors concluded that the clusters showed shared exposure patterns from single or multiple industrial sources. They noted incomplete coverage of southern regions, interview rates ranging from 45% to 95% between regions, and the use of residence at diagnosis as a stand-in for place of exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Geographic (spatial) cluster analysis of registry cases using a Bayesian hierarchical model, combined with individual exposure information from interviews
• Who was studied: 15,322 incident cases of malignant mesothelioma at all sites recorded by the Italian national mesothelioma registry (ReNaM), 1993–2008. The cases came from 16 of 20 Italian regions plus an autonomous province, covering almost 92% of the Italian population. This was 96.7% of all 15,845 cases recorded in that period.
• Exposure: Asbestos exposure assessed by expert review of interviews and classified as occupational (definite, probable or possible), familial (living with an asbestos worker), environmental (living near asbestos-using facilities or naturally occurring asbestos or asbestos-like minerals), other non-occupational, unlikely or unknown. Occupational and familial exposures were further described by industrial sector. No specific asbestos fiber types were analyzed, apart from fluoro-edenite fibers noted for Biancavilla.
• Main results:
  • Exposure was defined by interview for 11,852 of 15,322 cases (77.3%). Among interviewed subjects, asbestos exposure was ascertained in 86.4% (7,538/8,724) of men and 60.3% (1,888/3,128) of women.
  • Most cases (93%) were pleural mesothelioma.
  • 32 clusters of malignant mesothelioma were identified, mostly in Northern Italy (11 in the Northwest and 6 in the Northeast).
  • Asbestos cement manufacturing plants and shipyards were the main sources of asbestos-related mesotheliomas. Sectors with no direct use of asbestos (non-asbestos textiles, metal engineering, metal product manufacturing, construction) also contributed.
  • In clusters where the primary source was an asbestos cement industry, the proportion of cases with environmental exposure was above 15% (Casale Monferrato, Bari and Broni).
  • In the Genoa cluster (1,246 cases), shipyards were the largest exposure sector: 269 exposures, 17 familial and 252 occupational.
  • The authors described environmental cases as predominating in the Biancavilla cluster in eastern Sicily.
  • In Biancavilla, exposure was attributed to rocks from a local stone quarry containing fluoro-edenite fibers, which the article describes as an asbestiform amphibole-like mineral.
  • The authors suggested that the high number of cases in women in the two largest asbestos cement industry-centered clusters (Casale Monferrato and Broni) may be due to more common familial and environmental exposure.
• The authors' conclusion: The authors concluded that their data support shared exposure patterns in territorial clusters of malignant mesothelioma due to single or multiple industrial sources. They described their study as the first to integrate a Bayesian cluster analysis with standardized exposure data collection.
• Limitations the authors state:
  • Some regions, mainly in the South and Islands, did not contribute incidence data, which could partly explain fewer clusters detected in Southern Italy.
  • The percentage of cases interviewed varied between regions from 45% to 95%.
  • Cases with unknown exposure were negligible in some clusters but exceeded a fourth of defined cases in others.
  • The exposure coding system is entirely qualitative, so regions may have assigned exposure codes differently despite national guidelines.
  • Spatial smoothing can fail to detect excess risk in small areas.
  • The municipality of residence at diagnosis was used as a stand-in for the place of exposure.

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Balangero mine, Balangero, about 20 km north of Turin, Piedmont

All asbestos mines

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Malignant Mesothelioma, Mesothelioma, Asbestos-Cement, Environmental Exposure.

Related studies

• Malignant mesothelioma due to non-occupational asbestos exposure from the Italian national surveillance system (ReNaM): epidemiology and public health issues — A. Marinaccio, A. Binazzi, et al. (2015)
• Incidence of extrapleural malignant mesothelioma and asbestos exposure, from the Italian national register — A. Marinaccio, A. Binazzi, et al. (2010)
• Asbestos Exposure and Malignant Mesothelioma in Construction Workers-Epidemiological Remarks by the Italian National Mesothelioma Registry (ReNaM) — A. Binazzi, D. Di Marzio, et al. (2021)
• Association between asbestos exposure and pericardial and tunica vaginalis testis malignant mesothelioma: a case-control study and epidemiological remarks — A. Marinaccio, D. Consonni, et al. (2020)
• Pleural malignant mesothelioma epidemic: incidence, modalities of asbestos exposure and occupations involved from the Italian National Register — A. Marinaccio, A. Binazzi, et al. (2012)
• Non-occupational exposure to asbestos and malignant mesothelioma in the Italian National Registry of Mesotheliomas — D. Mirabelli, D. Cavone, et al. (2010)

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