Past trends and future prediction of mesothelioma incidence in an industrialized area of Italy, the Veneto Region

Our plain-English summary of Past trends and future prediction of mesothelioma incidence in an industrialized area of Italy, the Veneto Region, by P. Girardi, V. Bressan, E. Merler (Cancer Epidemiology, 2014).

The study

• Authors: P. Girardi, V. Bressan, E. Merler
• Journal: Cancer Epidemiology
• Published: 2014;38(5):496-503
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Malignant Mesothelioma (MM) is so associated with (professional, familial or environmental) asbestos exposure that trends in incidence and mortality parallel, after 30-40 years, the trend in asbestos consumption. In recent decades, the industrialized countries have witnessed a steady growth of pleural MM (MPM), following a stabilization or decline in rates in the countries that first adopted restrictive policies. The aim of this study was to evaluate the temporal variations of pleural MM incidence in the Veneto Region of Italy in the period 1987-2010.

Methods: We included only MPM with histological or cytological diagnosis. Age-Period-Cohort (APC) models were used to assess the trend in the incidence of MPM in both genders. Future predictions were evaluated by using a Bayesian APC model.

Results: In the period 1987-2010, 1600 MPMs have occurred. We observe a positive trend in the incidence in the whole period considered. The APC model showed that in both genders the cohort at higher risk is the one born between the years 1940-1945. Future projections indicate that the trend will decrease after the incidence peak of 2010; yet 1234 men are expected to develop a mesothelioma between 2011 and 2026. Among women, the future MPM rates will be stable or slightly decreasing.

Conclusions: The asbestos ban introduced in Italy in the year 1992 as a prospective result will certainly determine a decreasing incidence. However, the extremely long latency of MPM means that its influence is not yet observable.

Copyright © 2014 Elsevier Ltd. All rights reserved.

In plain English

This study used the Venetian Mesothelioma Registry to track pleural mesothelioma (cancer of the lining around the lungs) among residents of Italy's Veneto Region from 1987 to 2010. It used statistical age-period-cohort models to forecast cases up to 2026. Of 1749 mesothelioma cases, 1600 were pleural: 1178 in men and 422 in women. Pleural cases rose from 169 in 1987–1990 to 410 in 2007–2010, according to the article's tables; its text says 404. Asbestos exposure was classified as occupational in 80% of men and 29% of women. It was classified as non-occupational (domestic, environmental or hobby) in 4.4% of men and 33.7% of women. Risk was highest at ages 74–79. Among men, those born in 1940–1944 had the highest risk. The model estimated that cases in men peaked around 2010 and would then decline slightly. It predicted 1236 cases in men (95% interval 890 to 1626) and 378 in women (5–95% interval 235 to 607) in 2011–2026. The authors concluded that Italy's 1992 asbestos ban will contribute to a decrease, but its effect is not yet fully observable. They noted that better diagnostic tests may partly explain the rise.

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 registry study of mesothelioma incidence trends, analysed with age-period-cohort models, including a Bayesian age-period-cohort model used to predict future cases
• Who was studied: Residents of the Veneto Region, northeast Italy (4.5 million inhabitants in 2001), diagnosed with mesothelioma in 1987–2010 and recorded by the Venetian Mesothelioma Registry. There were 1749 mesothelioma cases, of which 1600 were pleural (1178 men, 422 women). Only 'definite' or 'probable' pleural cases with cytological or histological diagnosis were included.
• Exposure: Asbestos exposure was assessed by a standardized questionnaire and classified by an industrial hygienist. The categories were occupational (definite, probable or possible) and non-occupational (domestic, environmental, hobby). Industries named include the chemical industry, rail-road carriage and car construction and renovation, asbestos-cement, shipbuilding, construction and textiles. No fiber types are specified.
• Main results:
  • Pleural mesothelioma cases in Veneto residents increased over time, from 169 cases in 1987–1990 to 410 cases in 2007–2010 according to Tables 1 and 2. The text gives 404 for 2007–2010.
  • Among pleural cases, occupational asbestos exposure was assessed in 80% (946) of men and 29% (125) of women.
  • Among pleural cases, non-occupational exposure was assessed in 4.4% (51) of men and 33.7% (142) of women.
  • In both sexes the age group with the highest risk was 74–79. The median relative risk was 25.3 in men and 7.9 in women, compared with ages 44–49.
  • Among men, the birth cohort with the highest risk was born in 1940–1944, with a median relative risk of 1.79 compared with the 1920–1925 cohort. Among women the cohort effect was similar, with a median relative risk of 1.13.
  • Only among men did age groups up to 55 years show a clear declining trend since 2000. For women, rates appeared to increase in every age group.
  • For men, incidence was estimated to have peaked in 2010, with a slight decline thereafter. A total of 1236 pleural mesothelioma cases (95% CI: 890–1626) was predicted for 2011–2026.
  • For women, 378 pleural mesothelioma cases (5–95% CI: 235–607) were predicted for 2011–2026.
• The authors' conclusion: The authors concluded that past asbestos use and exposure caused a rising incidence of pleural mesothelioma in Veneto, stronger in men. They wrote that the incidence peak may have been reached around 2010, with rates expected to recede later than in other countries. They also concluded that the 1992 Italian asbestos ban will certainly contribute to decreasing incidence, but its influence is not yet fully observable.
• Limitations the authors state:
  • The analysis did not consider population dynamics or competing risks from other diseases.
  • The study was limited to a single region of Italy.
  • Only pleural mesotheliomas were evaluated; mesotheliomas at other sites were not considered.
  • Data on exposure intensity or asbestos consumption patterns were lacking, so these could not be added to the models.
  • Part of the increase may reflect better identification of the disease, through growing use of immuno-histochemical tests.
  • Because predictions stopped at 2026, the authors could not say when the decrease will reach its maximum.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Asbestos Exposure, Latency.

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