Environmental asbestos exposure and risk of mesothelioma

Our plain-English summary of Environmental asbestos exposure and risk of mesothelioma, by C.W. Noonan (Annals of Translational Medicine, 2017).

The study

• Author: C.W. Noonan
• Journal: Annals of Translational Medicine
• Published: 2017;5(11):234
• Type of article: Review
• Cited by: 88 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Mesothelioma is commonly considered an occupational disease occurring as a result of asbestos exposure in the workplace. Several avenues for environmental asbestos exposures have been described and may be associated with asbestos related disease, including mesothelioma. Worker take-home asbestos, or para-occupational exposure, has been well documented and is the most commonly reported pathway for asbestos exposure among mesothelioma cases that do not have history of occupational asbestos exposure. Observational studies have evaluated several communities with elevated mesothelioma incidence and environmental exposures attributed to local asbestos-related industries. Potential, but uncertain, mesothelioma risk also may be associated with general population asbestos exposure through contact with asbestos-containing commercial products, particularly housing materials that can be easily disturbed through normal activity. Finally, studies have described elevated mesothelioma incidence in several areas where populations are exposed to naturally occurring asbestos materials. These various environmental asbestos exposure pathways are poorly understood, and further studies should be pursued to evaluate their respective importance for population mesothelioma risk.

In plain English

This article was a review, not a new study. The author reviewed non-workplace asbestos exposure and mesothelioma in four groups: take-home (para-occupational) exposure, living near asbestos industries, asbestos-containing products such as building materials, and naturally occurring asbestos. A cited meta-analysis reported a summary odds ratio of 5.0 (95% confidence interval 2.5 to 10) for para-occupational exposure. A six-community study in Italy, Spain and Switzerland, excluding people with para-occupational exposure, reported an odds ratio of 12 (95% confidence interval 2.8 to 47) for living within 2000 meters of asbestos mines, asbestos cement plants, asbestos textile works, shipyards or brake factories. The author called commercial-product exposure poorly understood and noted that no health studies had evaluated whether a vermiculite attic insulation product was associated with mesothelioma or other asbestos-related diseases. Reports from typically rural areas with naturally occurring asbestos showed mesothelioma rates 100 to 800 times global background rates. The author concluded that evidence linking para-occupational exposure to mesothelioma was quite strong. Most cases are still attributed to occupations, but the author expected environmental cases to be a growing part of risk.

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: narrative review
• Who was studied: Published studies, case series and registry analyses of people with non-occupational asbestos exposure in many countries. No search method or number of included studies is stated.
• Exposure: Four non-occupational pathways: take-home (para-occupational) exposure from asbestos workers; environmental exposure from asbestos mines, asbestos cement plants, shipyards and other industries; asbestos-containing commercial products, especially housing materials; and naturally occurring asbestos including tremolite, chrysotile, fluoro-edenite, erionite and crocidolite
• Main results:
  • A meta-analysis cited in the review reported a summary odds ratio of 5.0 (95% CI 2.5 to 10) for para-occupational exposure and mesothelioma
  • A cited multi-center study of six communities in Italy, Spain and Switzerland excluded people with para-occupational exposure. It reported an odds ratio of 12 (95% CI 2.8 to 47) for living within 2000 meters of asbestos mines, asbestos cement plants, asbestos textiles, shipyards, or brake factories.
  • A cited study in Broni, Italy included only cases without occupational or para-occupational exposure. It reported a standardized incidence ratio of 13 (9.6 to 17) in Broni, 6.1 (3.9 to 9.4) in adjacent communities, and 1.2 (0.4 to 2.9) in more distant communities.
  • The author stated that no health studies had evaluated the exposure pathway involving Zonilite Attic Insulation (a vermiculite product) and its association with mesothelioma or other asbestos-related diseases
  • A cited Western Australian study found that about 5% of incident mesothelioma cases between 1960 and 2008 had home maintenance or renovation as the only known exposure route
  • The author described general population exposure to asbestos-containing commercial products as poorly understood, with health effects difficult to determine
  • Reports from areas with naturally occurring asbestos, typically rural, showed mesothelioma incidence 100 to 800 times higher than global background rates
  • A cited California study, adjusting for probable occupational exposure, found that each 10 km of greater distance from ultramafic rock was associated with a 6.3% reduced risk of mesothelioma (95% CI minus 10.5% to minus 1.8%)
• The authors' conclusion: The author concluded that evidence linking para-occupational exposure to mesothelioma is quite strong. The author also concluded that, although most cases are still attributed to occupations, cases associated with environmental exposures will be a measurable and growing component of risk.
• Limitations the authors state:
  • The author noted that data on take-home exposure concentrations are limited (a limitation of the evidence reviewed)
  • The author noted that in studies of non-occupational pathways it can be difficult to separate para-occupational exposure from residential exposure to industrial sources
  • The author noted that exposure misclassification may be too problematic in larger-scale studies with multiple industrial sources to detect robust associations

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Mesothelioma, Occupational Disease, Take-home Exposure, Environmental Exposure, naturally occurring asbestos (NOA).

Related studies

• Contribution of environmental factors to cancer risk — P. Boffetta, F. Nyberg (2003)
• Environmental exposure to asbestos and risk of pleural mesothelioma: review and meta-analysis — V. Bourdès, P. Boffetta, et al. (2000)
• Modeling mesothelioma risk associated with environmental asbestos exposure — M.M. Maule, C. Magnani, et al. (2007)
• Exposure to environmental chemicals and heavy metals, and risk of pancreatic cancer — S.O. Antwi, E.C. Eckert, et al. (2015)
• Environmental risk factors for pancreatic cancer: an update — E. Barone, A. Corrado, et al. (2016)
• Occupational and environmental risk factors for idiopathic pulmonary fibrosis in Australia: case-control study — M.J. Abramson, T. Murambadoro, et al. (2020)

Browse more research in Annals of Translational Medicine, or return to medical research.