Ophiolitic outcrops, naturally occurring asbestos exposure and mortality risk from malignant mesothelioma in Calabria (Southern Italy)

Our plain-English summary of Ophiolitic outcrops, naturally occurring asbestos exposure and mortality risk from malignant mesothelioma in Calabria (Southern Italy), by A. Scarselli, A. Marinaccio, S. Iavicoli (Public Health, 2021).

The study

• Authors: A. Scarselli, A. Marinaccio, S. Iavicoli
• Journal: Public Health
• Published: 2021;195:57-60
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: Naturally occurring asbestos from ophiolitic outcrops can pose a health risk to the resident population. Some studies have documented this risk of exposure in many areas around the world. The aim of the study is to estimate the possible impact on health caused by asbestos outcrops present in some areas of Calabria, a region of southern Italy.

Study Design: The design of the study is observational and uses routinely collected data on employment, compensations and mortality.

Methods: Data from archives of mortality in the period 2005-2015 were selected. Standardized mortality ratio (SMR) for malignant mesothelioma (MM) by municipalities of residence with reference to the regional population was estimated assuming a Poisson distribution of the data. Administrative archives of companies' employment records and occupational disease compensation data were used to exclude occupational origin cases.

Results: A total of 163 cases of MM were identified. Statistically significant excess risks (P-value <0.05) were observed for several municipalities, some of which were located in areas where asbestos outcrops had previously been identified. Significant SMRs vary between 44.0 and 5.2. The mean age at death in the areas at risk of ophiolitic outcrops ranges from 65.4 to 77.1 years, and the gender ratio (male/female) ranges from 0.66 to 1.3.

Conclusions: Monitoring of areas most involved in the risk of environmental contamination from ophiolitic outcrops is highly suggested. Full implementation of the local MM surveillance system is strongly encouraged. Further investigations are recommended to specifically identify the cause of exposure and confirm the hypothesis of a causal association with asbestos naturally occurring in these risk areas.

Copyright © 2021 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

In plain English

This short communication examined deaths from malignant mesothelioma among residents of Calabria, southern Italy, from 2005 to 2015. It looked for towns with more deaths than expected that might relate to asbestos occurring naturally in ophiolitic rock outcrops. National mortality records showed 163 mesothelioma deaths. The authors removed 17 cases compensated as occupational disease and 39 people who had worked in industries with a high or medium probability of asbestos exposure, leaving 107 cases. They compared each municipality with the regional population, adjusting for age and sex. They found statistically significant excesses in several municipalities inside outcrop risk areas identified by an earlier study, including Sorbo San Basile (the highest value), Marzi, San Giorgio Albanese and Martirano. Significant standardized mortality ratios ranged from 5.2 to 44.0. In these areas, mean age at death ranged from 65.4 to 77.1 years and the male-to-female ratio from 0.66 to 1.3. The authors said the findings supported the hypothesis of a link with natural environmental exposure, but that further studies were needed to confirm it.

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: Observational geographic mortality study (short communication) using routinely collected mortality, employment and compensation records; standardized mortality ratios (SMR) by municipality, adjusted for age and gender, assuming a Poisson distribution
• Who was studied: All malignant mesothelioma deaths (ICD-10 code C45, any site) among people living in a municipality of Calabria, southern Italy, at death, 2005 to 2015: 163 cases. 107 remained after excluding cases of certain or suspected occupational origin. Each municipality was compared with the regional population.
• Exposure: Presumed natural environmental exposure to asbestos from ophiolitic outcrops, based on residence in municipalities within risk areas identified by a previous study. This study did not measure exposure or name fiber types.
• Main results:
  • 163 malignant mesothelioma deaths were identified among Calabria residents, 2005 to 2015.
  • 17 cases of certain occupational origin (compensated by INAIL) and 39 of suspected occupational origin (employment in high or medium asbestos-exposure sectors) were excluded, leaving 107 cases for analysis.
  • Several municipalities within the previously identified ophiolitic outcrop risk areas had statistically significant excesses of mesothelioma deaths (P less than 0.05).
  • The highest SMR was in Sorbo San Basile. High SMRs were also found in Marzi, San Giorgio Albanese and Martirano, all within the identified risk areas.
  • Statistically significant SMRs ranged from 44.0 to 5.2. This range is stated only in the article's abstract; individual municipality values are not given in the text.
  • In these risk areas, mean age at death ranged from 65.4 to 77.1 years and the male-to-female ratio from 0.66 to 1.3.
• The authors' conclusion: The authors concluded that the excess mesothelioma mortality in municipalities of the identified risk areas supported the hypothesis of a causal link with natural environmental exposure. They said further environmental epidemiological studies are needed to confirm it.
• Limitations the authors state:
  • Work outside Italy could not be considered because work histories were missing. The authors note this matters in Calabria because of high past emigration.
  • Some occupational cases may have been missed because of incorrect matching of records between archives.
  • Treating everyone who worked in a high or medium risk sector as occupationally exposed may have excluded some non-occupational cases.
  • The authors could not distinguish environmental exposure from human activities, or family exposure, from naturally occurring exposure.
  • The administrative archives used to select cases are generally of lower quality than epidemiological data.
  • Possible overdispersion bias; the authors call for further analysis using a Bayesian approach.

Topics

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

Medical terms in this study, explained in our Lexicon: naturally occurring asbestos (NOA), Malignant Mesothelioma, standardized mortality ratio (SMR), Occupational Disease, P-Value.

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