Mesothelioma and non-occupational environmental exposure to asbestos

Our plain-English summary of Mesothelioma and non-occupational environmental exposure to asbestos, by C. Magnani, G. Borgo, G.P. Betta, et al (Lancet, 1991).

The study

• Authors: C. Magnani, G. Borgo, G.P. Betta, M. Botta, C. Ivaldi, F. Mollo, M. Scelzi, B. Terracini
• Journal: Lancet
• Published: 1991;338(8758):50
• Type of article: Letter
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004461).

Summary of the article

This letter asked whether pleural mesothelioma occurred in excess among residents of Casale Monferrato, north-west Italy, apart from occupational exposure. The town, with about 40 000 people, was the site of the largest Italian asbestos-cement plant, which operated from 1907 to 1985. In an earlier mortality study of the plant's workers for 1964-86, the authors had found 864 deaths against 710 expected, including 117 from lung cancer, 43 from pleural cancer and 89 from asbestosis. For this report, the authors searched the records of the local hospital and four other large hospitals for histological diagnoses of pleural mesothelioma among residents of the local health unit. The area was divided into three zones: Casale Monferrato itself, adjacent towns, and other towns and villages. They found 89 residents with a histological diagnosis during 1980-89. Linkage with employee rosters showed that 26 had worked at the plant, and 3 were wives of workers. The remaining 60 cases were used to calculate rates, which were compared with rates from the Varese Province cancer registry for 1976-87. The authors reported an impressive excess of pleural mesothelioma in both men and women that was not attributable to work at the plant. The numbers were small, but rates appeared to fall with distance from Casale Monferrato. They discussed possible biases and concluded that a cancer risk from asbestos may arise in the general, non-occupational environment.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This short letter to the editor estimated how often pleural mesothelioma occurred among residents served by the local health unit of Casale Monferrato, north-west Italy. The town was home to the largest Italian asbestos-cement plant, which operated during 1907-85. Searching the records of the local hospital and four other large hospitals, the authors found 89 residents with a histological diagnosis of mesothelioma during 1980-89. Of these, 26 had worked at the plant and 3 were wives of plant workers. The other 60 cases were used to calculate rates, which were compared with rates from the Varese Province cancer registry for 1976-87. The authors reported what they called an "impressive excess" of pleural mesothelioma in men and women that was not attributable to work at the plant. With small numbers, there seemed to be a downward gradient with distance from Casale Monferrato. The rates themselves were in a table that is missing from this text. The authors noted possible biases, including overcounting of cases and unrecognized work exposure, such as asbestos work other than asbestos-cement work. They concluded that their findings suggest a cancer risk from asbestos may arise in the general, non-occupational environment.

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: Letter to the editor reporting a hospital-records survey of the incidence of pleural mesothelioma among residents of an area, with rates compared against a cancer registry
• Who was studied: Residents of the area of the local health unit of Casale Monferrato, north-west Italy, divided into three zones (Casale Monferrato itself, adjacent towns, other towns and villages); 89 residents with a histological diagnosis of mesothelioma during 1980-89, found in the records of the local hospital and four other large hospitals. Cytological diagnoses on pleural fluid were not included.
• Exposure: Non-occupational environmental exposure to asbestos among residents near the largest Italian asbestos-cement plant, which operated during 1907-85. Occupational exposure at the plant was checked against employee rosters. The letter does not name fiber types.
• Main results:
  • Of the 89 residents with mesothelioma, 26 had worked at the plant at some time after 1907 and 3 others were wives of plant workers. The remaining 60 cases were used to compute rates, which were compared with rates estimated by the Varese Province cancer registry for 1976-87.
  • Among both men and women, the authors described an "impressive excess" of pleural mesothelioma not attributable to occupational exposure in the plant. The rates and rate ratios were in a table that is not reproduced in this text.
  • The numbers were small, but there seemed to be a downward gradient in rates with distance from Casale Monferrato.
• The authors' conclusion: The authors concluded that their findings suggest a risk of cancer from asbestos exposure may arise in the general (non-occupational) environment, a subject they described as having been controversial until then.
• Limitations the authors state:
  • Overcounting of cases, or underestimation of occupational exposure, could bias the results toward an excess linked to non-occupational exposure.
  • Occupational exposure to asbestos in work other than asbestos-cement work could not be excluded. The authors argued that any bias from this should be small.
  • The numbers of cases were small.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Environmental Exposure, Pleural Mesothelioma, Casale Monferrato, Occupational Exposure, Asbestos-Cement, Lung Cancer, Cancer Registry.

Related studies

• Asbestos lung burden and asbestosis after occupational and environmental exposure in an asbestos cement manufacturing area: a necropsy study — C. Magnani, F. Mollo, et al. (1998)
• Multicentric study on malignant pleural mesothelioma and non-occupational exposure to asbestos — C. Magnani, A. Agudo, et al. (2000)
• Occupational and environmental exposures and lung cancer in an industrialised area in Italy — V. Fano, P. Michelozzi, et al. (2004)
• Pleural mesothelioma and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment — D. Ferrante, D. Mirabelli, et al. (2016)
• A cohort study on mortality among wives of workers in the asbestos cement industry in Casale Monferrato, Italy — C. Magnani, B. Terracini, et al. (1993)
• Environmental asbestos exposure and clustering of malignant mesothelioma in community: a spatial analysis in a population-based case-control study — C. Airoldi, C. Magnani, et al. (2021)

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