Impact of an asbestos cement factory on mesothelioma incidence in a community in Italy

Our plain-English summary of Impact of an asbestos cement factory on mesothelioma incidence in a community in Italy, by D. Consonni, S. De Matteis, B. Dallari, et al (Environmental Research, 2020).

The study

• Authors: D. Consonni, S. De Matteis, B. Dallari, A.C. Pesatori, L. Riboldi, C. Mensi
• Journal: Environmental Research
• Published: 2020;183:108968
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Broni is a small town (9000 inhabitants) in the province of Pavia, Lombardy, north-west Italy, where the second largest Italian asbestos cement factory (Fibronit) was in operation between 1932 and 1993. Based on Lombardy Mesothelioma Registry (RML) data (2000-2011), we previously showed a high impact of asbestos exposure on malignant mesothelioma (MM) incidence among Fibronit workers, their families, and people living in Broni and in the nearby town of Stradella (11,000 residents). Given the great concern of the community, we have recently updated the data regarding 5 more years (2012-2016).

Methods: From the RML database we extracted subjects who ever worked in Fibronit, their family members, ever residents in Broni, and subjects living in Stradella and nearby towns at the time of diagnosis. For each type of exposure we calculated standardized incidence ratios (SIR = observed/expected cases).

Results: In the period 2000-2016 we registered 56 cases (2.52 expected, SIR = 22.2), 49 men (41 pleural, 8 peritoneal MM), 7 women (5 pleural, 2 peritoneal MM) with past occupational exposure in Fibronit. Among subjects never occupationally exposed and never exposed to extra-occupational sources unrelated to Fibronit, we counted 39 cases (4.24 expected, SIR = 9.2), 10 men (all pleural MM), 29 women (28 pleural, 1 peritoneal MM) in Fibronit workers' families, 91 pleural mesothelioma cases (7.43 expected, SIR = 12.2, 31 men, 60 women), ever residents in Broni, and 25 pleural mesothelioma cases (3.05 expected, SIR = 8.2, 6 men, 19 women) living in Stradella at the time of diagnosis. The overall number of excess cases was about 194 (211 against 17.24 expected). In the remaining adjacent (No. 8) and surrounding (No. 17) municipalities (32,000 people) there were 7 cases (1 men, 6 women, 8.85 expected).

Conclusion: The mesothelioma burden related to the asbestos cement factory is still high on factory workers, their families, and residents in Broni and Stradella towns.

Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.

In plain English

This registry study counted mesothelioma cases diagnosed in 2000 to 2016 among people living in Lombardy, Italy, that the authors linked to Fibronit, an asbestos cement factory in Broni. The factory, in operation from 1932, stopped using asbestos in 1993 and closed in 2000. It updated the authors' 2000 to 2011 analysis. Cases were grouped as former workers, people who had lived with a worker, and people who had ever lived in Broni or lived in Stradella at diagnosis. The non-worker groups excluded anyone exposed at work or from sources unrelated to Fibronit. Observed cases were compared with numbers expected from regional rates in never-exposed people. The authors found 56 cases among workers (2.52 expected), 39 among household members (4.24 expected), 91 among ever-residents of Broni (7.43 expected) and 25 in Stradella (3.05 expected). That is about 194 more than expected. No clear excess appeared in 25 other nearby towns. National rates roughly halved the ratios, mainly in men. The authors noted that populations at risk were roughly estimated and cases probably undercounted. They concluded that the factory's impact on the community continues.

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: Population-based mesothelioma registry study, an update of the authors' earlier 2000 to 2011 analysis. The Lombardy Mesothelioma Registry collects cases diagnosed in people living in Lombardy at the time of diagnosis, including those reported by hospitals outside the region. The study compared observed with expected cases using standardized incidence ratios (SIRs) with 90% confidence intervals.
• Who was studied: The registry recorded 6226 malignant mesothelioma cases first diagnosed from 1 January 2000 to 31 December 2016 in people living in Lombardy, Italy. Of these, 5835 were interviewed; the 391 without interview were excluded. Among them, 218 cases in the Broni area (province of Pavia) had exposure the authors related to Fibronit. These were former workers, cohabitants of workers, people who ever lived in Broni, and residents at diagnosis of Stradella and of 8 adjacent and 17 surrounding towns. The familial and environmental groups excluded people with occupational exposure (at Fibronit or elsewhere) and people with extra-occupational exposure unrelated to Fibronit. People with both familial and Broni environmental exposure were assigned to one group case by case.
• Exposure: Asbestos from the Fibronit asbestos cement factory in Broni, the second largest in Italy. The factory was in operation from 1932, completely stopped using asbestos in 1993, continued cement production until 1997 and closed in 2000. Exposure was grouped as occupational (ever worked in the factory), familial (ever lived with a Fibronit worker) and environmental (ever lived in Broni, or resided in Stradella at diagnosis). The article does not name the asbestos fiber types used.
• Main results:
  • Former Fibronit workers: 56 cases against 2.52 expected, SIR 22.2 (90% CI 17.6 to 27.8). Men: 49 cases (41 pleural, 8 peritoneal), SIR 20.6 (90% CI 16.0 to 26.1). Women: 7 cases (5 pleural, 2 peritoneal), SIR 50.0 (90% CI 23.5 to 93.9).
  • Pleural plaques among the affected workers: 26 of the men (53.1%) and 4 of the women (57.1%).
  • Cohabitants of Fibronit workers (familial exposure): 39 cases against 4.24 expected, SIR 9.2 (90% CI 6.9 to 12.0). Men: 10 cases, all pleural, SIR 3.8. Women: 29 cases (28 pleural, 1 peritoneal), SIR 17.7.
  • People who had ever lived in Broni: 91 pleural mesothelioma cases against 7.43 expected, SIR 12.2 (90% CI 10.2 to 14.6). Men: 31 cases, SIR 8.1. Women: 60 cases, SIR 16.7.
  • Residents of Stradella at diagnosis: 25 pleural mesothelioma cases against 3.05 expected, SIR 8.2 (90% CI 5.7 to 11.4). Men: 6 cases, SIR 3.8. Women: 19 cases, SIR 13.0.
  • Across workers, cohabitants, Broni and Stradella combined: 211 cases against 17.24 expected, about 194 excess cases over the 17-year period.
  • Other nearby towns: no clear excess. The 8 other adjacent towns had 1 case against 2.13 expected. The 17 surrounding towns had 6 cases against 6.72 expected.
  • Sensitivity analysis using national rates: total expected cases rose to 51.26 (from 26.09) and overall SIRs were roughly halved, with the largest reductions in men. For example, men with familial exposure had SIR 1.6 (90% CI 0.9 to 2.7). The four Fibronit-related groups still showed 177 excess cases (211 against 33.97 expected).
• The authors' conclusion: The authors concluded that the study provided evidence of a continuing large impact of the Fibronit asbestos cement factory on the local community. They expect many more cases among former workers, their families and residents of Broni and Stradella, and they called for continued monitoring.
• Limitations the authors state:
  • People who moved out of Lombardy are not covered by the registry.
  • Only the last place of residence is stored, except for Broni residents, so the authors state that the number of Fibronit-related cases is probably underestimated.
  • Without defined cohorts, the populations at risk (workers, cohabitants, Broni residents) could only be roughly estimated. For example, the authors assumed two family members per worker and a 10% yearly population turnover in Broni.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos-Cement, Mesothelioma, Asbestos Exposure, Standardized Incidence Ratio (SIR), Occupational Exposure, Pleural Mesothelioma.

Related studies

• Impact of an asbestos cement factory on mesothelioma incidence: global assessment of effects of occupational, familial, and environmental exposure — C. Mensi, L. Riboldi, et al. (2015)
• Incidence of mesothelioma in Lombardy, Italy: exposure to asbestos, time patterns and future projections — C. Mensi, S. De Matteis, et al. (2016)
• Estimate of environmental and occupational components in the spatial distribution of malignant mesothelioma incidence in Lombardy (Italy) — D. Catelan, D. Consonni, et al. (2020)
• Gender differences in pleural mesothelioma occurrence in Lombardy and Piedmont, Italy — D. Consonni, E. Migliore, et al. (2019)
• Peritoneal mesothelioma and asbestos exposure: a population-based case-control study in Lombardy, Italy — D. Consonni, C. Calvi, et al. (2019)
• Mesothelioma in Agriculture in Lombardy, Italy: An Unrecognized Risk — C. Mensi, B. Dallari, et al. (2021)

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