Asbestos burden in lungs of non-occupationally exposed women from Broni (Pavia, Italy): a postmortem SEM-EDS study

Our plain-English summary of Asbestos burden in lungs of non-occupationally exposed women from Broni (Pavia, Italy): a postmortem SEM-EDS study, by S.D. Visonà, S. Capella, P. Borrelli, et al (Journal of Thoracic Disease, 2023).

The study

• Authors: S.D. Visonà, S. Capella, P. Borrelli, S. Villani, C. Favaron, Z. Kurzhunbaeva, C. Colosio, E. Belluso
• Journal: Journal of Thoracic Disease
• Published: 2023;15(12):6555-6569
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: In Italy the incidence of malignant mesothelioma (MM) among women is remarkably high, due to the several contexts in which women had been exposed to asbestos. However, very few studies in literature focus on the inorganic lung content in women. The aim of this retrospective, observational study is to investigate the asbestos lung burden, in terms of concentration, dimensions and type of asbestos, in 42 women who died from MM and had been non-occupationally exposed to asbestos during the activity of the asbestos-cement plant located in Broni (Pavia, Northern Italy) where mainly chrysotile, crocidolite and amosite were used.

Methods: Lung samples taken during forensic autopsies have been digested using sodium hypochlorite and filtered through a cellulose-ester membrane. The filter was examined using a scanning electron microscope and the chemical composition of the fibers was analyzed using an electron dispersive spectroscopy. The number of detected inorganic fibers, asbestos fibers and asbestos bodies (ABs) were normalized to 1 gram of dry tissue.

Results: In six samples no asbestos has been detected. Overall, the most represented kind of asbestos was amosite, followed by crocidolite, tremolite/actinolite asbestos and chrysotile. The concentration of all inorganic fibers was significantly higher in women with environmental and household exposures compared with those with only environmental exposure (P=0.025), as well as the concentration of asbestos fibers (P=0.019) and ABs (P=0.049). We found a significant correlation between the concentration of asbestos fibers and the duration of exposure (rho =0.413, P=0.008), as well as with the latency of MM (rho =0.427, P=0.005). The distance of the residential address from the factory and the time spent daily in contact with asbestos did not influence the lung asbestos burden.

Conclusions: These results suggest the relevance of the lung clearance of asbestos, regarding mainly chrysotile. As a consequence, although scanning electron microscopy -energy dispersive X-ray spectroscopy (SEM-EDS) is considered the most reliable tool for assessing previous exposure to asbestos, its results should be interpreted with caution, especially in a legal context. In addition, our data confirm the relevance of environmental and household exposure in determining asbestos concentration in lungs and highlight the importance of household exposure.

2023 Journal of Thoracic Disease. All rights reserved.

In plain English

This retrospective study examined lung tissue from forensic autopsies, between 2005 and 2018, of 42 women who died of malignant mesothelioma. None had worked with asbestos; all were exposed through the Fibronit asbestos-cement plant in Broni, northern Italy. Twenty-eight had environmental exposure only, and 14 had environmental exposure and also lived with an asbestos worker. Using electron microscopy, the authors found no asbestos in 6 of the 42 lung samples. Of the asbestos detected, 43% was amosite, 31% crocidolite, 24% tremolite/actinolite asbestos and 2% chrysotile/asbestiform antigorite. Women with household plus environmental exposure had a median of 42,998.1 asbestos fibers per gram of dry lung, compared with 20,751.1 in women with environmental exposure alone (P=0.019). Asbestos concentration correlated with duration of exposure and with latency. Distance from the plant showed no correlation, and daily time exposed made no significant difference to overall asbestos concentration, although women exposed most of the day had significantly more tremolite/actinolite asbestos and wider asbestos fibers. The authors concluded that, because lungs clear asbestos, especially chrysotile, these measurements should be interpreted with caution, especially in a legal context.

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: Retrospective cohort design: postmortem analysis of lung samples by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS)
• Who was studied: 42 women who died of malignant mesothelioma and had a forensic autopsy between 2005 and 2018, all non-occupationally exposed in Broni (Pavia, Italy). They were selected from 46 women among 188 autopsied subjects who died of asbestos-related diseases. 4 were excluded (3 with only occupational or household exposure, 1 with no reported exposure). 28 had anthropogenic environmental exposure only (AEE) and 14 had anthropogenic environmental and household exposure (AEH).
• Exposure: Non-occupational exposure from the Fibronit asbestos-cement plant in Broni (active 1932 to 1993), whose raw materials were chrysotile, crocidolite and small amounts of amosite. Exposure was environmental (living in the area) or environmental plus household (also living with an asbestos worker).
• Main results:
  • 6 of the 42 women had no asbestos in the lung sample examined (5 in the AEE group, 1 in the AEH group); 3 of these had no inorganic fibers of any kind.
  • Asbestos bodies were found in 13 of the 42 women; short fibers were found in 29.
  • Of all asbestos detected across the series, amosite made up 43%, crocidolite 31%, tremolite/actinolite asbestos 24% and chrysotile/asbestiform antigorite 2%.
  • Inorganic fibers: median 92,700.6 fibers per gram of dry lung in the AEH group (n=14) versus 44,387.2 in the AEE group (n=28), P=0.025. Asbestos fibers: median 42,998.1 (AEH) versus 20,751.1 (AEE), P=0.019. Both differences were significant.
  • Asbestos bodies: median 2,228.3 per gram of dry lung in the AEH group versus 0.0 in the AEE group (P=0.049). The results section describes this excess as borderline significant.
  • Among individual asbestos types, only crocidolite was significantly higher in the AEH group (median 11,172.6 versus 0.0 fibers per gram of dry lung, P=0.007). Chrysotile/asbestiform antigorite, amosite and tremolite/actinolite asbestos did not differ significantly between the groups.
  • Across all women, asbestos fiber concentration correlated with duration of exposure (rho 0.413, P=0.008) and with latency of mesothelioma (rho 0.427, P=0.005). The authors described the correlation with duration as quite weak.
  • Concentrations of inorganic fibers, asbestos and asbestos bodies did not differ significantly between two groups: women who spent most of their day exposed (lived and worked in Broni or were housewives, n=29) and women exposed for only part of the day (n=7).
  • Women exposed for most of the day (n=29) had significantly higher tremolite/actinolite asbestos concentration than women exposed for only part of the day (n=7): median 4,851.4 versus 0.0 fibers per gram of dry lung, P=0.006. The other asbestos types did not differ significantly.
  • Asbestos fibers were significantly wider in women exposed most of the day (median of mean width 0.6 µm) than in women exposed for part of the day (0.3 µm), P=0.009. Fiber length did not differ.
  • No correlation was observed between the distance of home or workplace from the plant and the amount of asbestos in the lungs.
  • Lung content did not differ significantly by histological type of mesothelioma. Women with epithelioid mesothelioma survived significantly longer than those with sarcomatoid or biphasic/desmoplastic types.
• The authors' conclusion: The authors concluded that household exposure added to environmental exposure significantly increases lung asbestos concentration. They also concluded that, because of asbestos clearance (mainly of chrysotile), postmortem SEM-EDS results do not exactly reflect how much asbestos was inhaled and should be interpreted with caution, especially in a legal context.
• Limitations the authors state:
  • The women were drawn from forensic autopsies ordered by the Prosecutor, so they do not represent all women exposed in Broni who died of mesothelioma. The authors considered selection bias unlikely.
  • Only a relatively small amount of lung tissue (one sample per woman) was examined.
  • SEM-EDS examines less tissue than optical microscopy, so asbestos bodies may have been undercounted.

Topics

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Asbestos-Cement, Chrysotile, Crocidolite, Amosite, Asbestos Bodies, Tremolite, Actinolite.

Related studies

• Evaluation of Deposition and Clearance of Asbestos (Detected by SEM-EDS) in Lungs of Deceased Subjects Environmentally and/or Occupationally Exposed in Broni (Pavia, Northern Italy) — S.D. Visonà, S. Capella, et al. (2021)
• Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples — S.D. Visonà, S. Capella, et al. (2021)
• Reply to Mirabelli et al. Is Mesothelioma Unrelated to the Lung Asbestos Burden? Comment on "Visonà et al. Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples. Int. J. Environ. Res. Public Health 2021, 18, 2053" — S.D. Visonà, S. Capella, et al. (2021)
• Is Mesothelioma Unrelated to the Lung Asbestos Burden? Comment on Visonà et al. Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples. Int. J. Environ. Res. Public Health 2021, 18, 2053 — D. Mirabelli, A. Angelini, et al. (2021)
• A postmortem case control study of asbestos burden in lungs of malignant mesothelioma cases — S.D. Visonà, B. Bertoglio, et al. (2023)
• Impact of asbestos on public health: a retrospective study on a series of subjects with occupational and non-occupational exposure to asbestos during the activity of Fibronit plant (Broni, Italy) — S.D. Visonà, S. Villani, et al. (2018)

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