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)

Our plain-English summary of 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), by S.D. Visonà, S. Villani, F. Manzoni, et al (Journal of Public Health Research, 2018).

The study

• Authors: S.D. Visonà, S. Villani, F. Manzoni, Y. Chen, G. Ardissino, F. Russo, M. Moretti, G.T. Javan, A. Osculati
• Journal: Journal of Public Health Research
• Published: 2018;7(3):1519
• Cited by: 23 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The goal of this study is to understand more about the role of asbestos in causing human diseases, first of all mesothelioma, by investigating a large series of deaths due to asbestos-related diseases (ARDs). The main aim is to clarify if even very low amounts of asbestos can cause mesothelioma and other ARDs, as well as to find out if a different individual vulnerability can be important. This retrospective study included 188 subjects who died from asbestos related diseases in 2000-2017 in the area around Broni, Italy, where an important asbestos cement factory had been active from 1932 until 1993. In each case, a forensic autopsy has been performed. In order to perform the present study, the records were retrieved, including the clinical files, the autopsy, and the histological report. The statistical analysis performed showed that there was a significant relation between the cause of death (mesothelioma, lung cancer or asbestosis) and the kind of exposure (occupational, neighborhood or household), showing that all the subjects not exposed occupationally (and, therefore, exposed to lower amounts of asbestos) died from mesothelioma, whereas the individuals who used to work at the plant died also from other caused (asbestosis, lung cancer). Significant differences were highlighted examining the distribution of the causes of death according to the smoking habits. Moreover, among the mesothelioma patients, the survival time was shorter in the subjects with a neighborhood or household exposure than in the occupationally exposed individuals. The study provided meaningful data about the role of asbestos in causing human pathologies. In particular, the present data appear to support the hypothesis that even an exposure to a very little amount of asbestos can cause mesothelioma in hypersusceptible subjects (probably, on a genetic basis).

In plain English

This retrospective study reviewed records of 188 people who died from asbestos-related diseases between 2000 and 2017, each examined by forensic autopsy. Almost all had worked and/or lived in Broni, Italy, where the Fibronit asbestos-cement plant used chrysotile, crocidolite and amosite from 1932 to 1993. Table 2's counts of causes of death add up to one person fewer than the 188 studied, and the article does not explain why: mesothelioma 149 (79.7%), asbestosis 20 (10.7%), lung cancer 12 (6.4%). Of 109 people with occupational exposure, 67.0% died of mesothelioma, 17.4% of asbestosis and 11.0% of lung cancer. All 73 without occupational exposure died of mesothelioma. Survival after a mesothelioma diagnosis was longer in men than women (median 2 years versus 1 year) and longer in occupationally exposed people than in others. The authors concluded their data appear to support the hypothesis that even very low asbestos exposure can cause mesothelioma in hypersusceptible people, probably on a genetic basis. They noted that cases were included only if referred for forensic autopsy, and that mesothelioma deaths were more likely to be referred than deaths from other diseases.

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 study of a case series of deaths from asbestos-related diseases, all examined by forensic autopsy. The records reviewed were clinical files, autopsy reports and histological reports.
• Who was studied: 188 people who died from asbestos-related diseases in 2000 to 2017. All underwent forensic autopsy at the Section of Legal Medicine and Forensic Sciences, University of Pavia. Almost all formerly worked and/or lived in Broni, Italy. 66% were male.
• Exposure: Asbestos from the Fibronit asbestos-cement plant in Broni (active 1932 to 1993), which used mixtures of chrysotile, crocidolite and amosite (the article says amosite was used in small quantities, as an additive). Exposure was classed as occupational, neighborhood (environmental) or household, and some people had more than one type.
• Main results:
  • Causes of death in Table 2: mesothelioma 149 (79.7%), asbestosis 20 (10.7%), lung cancer 12 (6.4%), other tumors 3 (1.6%), other cardiopulmonary pathologies 3 (1.6%). These counts add up to one person fewer than the 188 in the study, and the article does not explain the missing person.
  • Among the 109 occupationally exposed people, about 67% died from mesothelioma, 17.4% from asbestosis and 11% from lung carcinoma. The remainder died from other cancers or cardiopulmonary diseases.
  • All 73 people without occupational exposure died from mesothelioma. The difference in cause of death by occupational exposure was statistically significant (Fisher's exact test, P less than 0.001). Differences by household exposure (P=0.051) and neighborhood exposure (P=0.96) were not significant.
  • Among 143 people with known smoking habits (Table 4, P=0.01), mesothelioma was the cause of death in 92.2% of never-smokers (n=51) and 93.3% of current smokers (n=15). Among ex-smokers (n=77), it was the cause in 67.5%, with 13.0% dying from asbestosis and 15.6% from lung cancer.
  • Among people with mesothelioma, survival after diagnosis was significantly higher in men than in women (Tarone-Ware test 6.92; P=0.0085). Median survival was 2 years in men versus 1 year in women.
  • Survival after a mesothelioma diagnosis was significantly higher in occupationally exposed people than in those with other kinds of exposure (Tarone-Ware test 16.49; P less than 0.0001).
  • Among the 149 who died from mesothelioma, mean latency from first environmental exposure was 55.4 years (SD 13.7) in males versus 52.7 years (SD 17.7) in females. This difference was not statistically significant (P=0.38).
  • Median latency from first occupational exposure for mesothelioma was 45 years (IQR 36 to 50) in men versus 55 years (IQR 42 to 58) in women, with P=0.06. The authors called this borderline statistical significance.
• The authors' conclusion: The authors concluded that their data appear to support the hypothesis that even a very small exposure to asbestos can cause mesothelioma in hypersusceptible people, probably on a genetic basis. They also wrote that, in their series, cigarette smoke cannot be identified as the missing piece in mesothelioma among people with low exposure.
• Limitations the authors state:
  • The series is not comparable to an epidemiological cohort, because people were included only if a forensic autopsy had been performed.
  • Mesothelioma deaths were always reported to the Prosecutor. Deaths from other asbestos-related diseases, whose link with asbestos is less well known (such as lung carcinoma), may not have been.
  • Environmental asbestos concentrations were measured only between 1981 and 1990. They were never measured in the 1950s and 1960s, when the authors believe the most relevant exposures probably occurred.

Topics

Medical terms in this study, explained in our Lexicon: Non-Occupational Exposure, Mesothelioma, Asbestos-Cement, Autopsy, Lung Cancer, Habit.

Related studies

• 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)
• 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)
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