Incidence of mesothelioma in Lombardy, Italy: exposure to asbestos, time patterns and future projections

Our plain-English summary of Incidence of mesothelioma in Lombardy, Italy: exposure to asbestos, time patterns and future projections, by C. Mensi, S. De Matteis, B. Dallari, et al (Occupational and Environmental Medicine, 2016).

The study

• Authors: C. Mensi, S. De Matteis, B. Dallari, L. Riboldi, P.A. Bertazzi, D. Consonni
• Journal: Occupational and Environmental Medicine
• Published: 2016;73(9):607-13
• Cited by: 39 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: In Italy, asbestos has been extensively used from 1945 to 1992. We evaluated the impact of exposure to asbestos on occurrence of malignant mesothelioma (MM) in the Lombardy Region, Northwest Italy, the most populated and industrialised Italian region.

Methods: From the Lombardy Mesothelioma Registry, we selected all incident cases of MM diagnosed between 2000 and 2012. We described sources of exposure to asbestos and examined time trends of MM rates. Using Poisson age-cohort models, we derived projections of burden of MM in the Lombardy population for the period 2013-2029.

Results: In 2000-2012, we recorded 4442 cases of MM (2850 men, 1592 women). Occupational exposure to asbestos was more frequent in men (73.6%) than in women (38.2%). Non-occupational exposure was found for 13.6% of women and 3.6% of men. The average number of cases of MM per year was still increasing (+3.6% in men, +3.3% in women). Incidence rates were still increasing in individuals aged 65+ years and declining in younger people. A maximum of 417 cases of MM (267 men, 150 women) are expected in 2019. We forecast there will be 6832 more cases (4397 in men, 2435 in women) in the period 2013-2029, for a total of 11 274 cases of MM (7247 in men, 4027 in women) in 30 years.

Conclusions: This study documented a high burden of MM in both genders in the Lombardy Region, reflecting extensive occupational (mainly in men) and non-occupational (mainly in women) exposure to asbestos in the past. Incidence rates are still increasing; a downturn in occurrence of MM is expected to occur after 2019.

Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

In plain English

This study used the population-based Lombardy Mesothelioma Registry in northwest Italy. It described all 4442 cases of malignant mesothelioma diagnosed in residents between 2000 and 2012 (2850 men, 1592 women), tracked trends, and projected cases with age-cohort models. Patients or relatives were interviewed about lifetime asbestos exposure. Occupational exposure was found in 73.6% of men and 38.2% of women. Exposure through cohabitants, home or environment was found in 13.6% of women and 3.6% of men. No exposure was identified at interview in 17.3% of men and 39.2% of women. Of occupationally exposed women, 65.5% had been exposed in non-asbestos textile and clothing production. More than 90% of cases arose in the pleura. Yearly cases rose from 277 in 2000 to 403 in 2012. Rates rose in people aged 65 and over and fell in younger people. The models projected a peak of 417 cases in 2019 and 6832 further cases (90% confidence interval 5333 to 9184) in 2013 to 2029. The authors concluded this reflected extensive past occupational (mainly men) and non-occupational (mainly women) exposure. They noted that interviews may miss exposures.

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: description of incident cases and their asbestos exposure, analysis of time trends 2000-2012, and projections for 2013-2029 using Poisson age-cohort models
• Who was studied: All 4442 residents of the Lombardy Region, Italy, diagnosed with malignant mesothelioma between 1 January 2000 and 31 December 2012: 2850 men (64.2%) and 1592 women (35.8%). Median age at diagnosis was 70.4 years in men and 73.8 years in women.
• Exposure: Lifetime asbestos exposure was assessed by standardised interview with patients or next of kin. It was classified as occupational (certain, probable or possible), para-occupational (through cohabitants), home-related, or environmental. Fiber types were not reported for the cases.
• Main results:
  • Occupational asbestos exposure was documented in 73.6% of men and 38.2% of women with mesothelioma.
  • Para-occupational, home-related and environmental exposures were more frequent in women (13.6% in total) than in men (3.6%).
  • No evidence of asbestos exposure was found at interview for 493 men (17.3%) and 624 women (39.2%).
  • Among occupationally exposed women, 65.5% had been exposed in the non-asbestos textile and clothing production sectors. Among men, about one-third had been exposed in metalmechanic and metallurgy industries and one-third in building construction.
  • The pleura was the site of origin in more than 90% of cases: 2693 men (94.5%) and 1462 women (91.8%). Peritoneal mesothelioma occurred in 134 men and 125 women.
  • Yearly cases rose from 277 in 2000 to 403 in 2012, an average increase of 3.6% per year in men and 3.3% per year in women.
  • Crude rates per 100 000 person-years went from 4.0 to 5.8 in men. The average yearly increase was 2.6% crude and 1.3% age-adjusted. In women, crude rates went from 2.2 to 2.6, with yearly increases of 2.5% crude and 1.6% age-adjusted.
  • Annual rate changes were +3.4% in men and +3.5% in women aged 65 years and over. In those under 65, they were minus 3.0% in men and minus 4.3% in women.
  • The projected peak was in 2019 for both genders: 267 cases in men and 150 in women, a total of 417.
  • Projected further cases numbered 6832 (90% CI 5333 to 9184): 4397 (90% CI 3505 to 5860) in men and 2435 (90% CI 1828 to 3324) in women. The total for 2000-2029 was 11 274 (90% CI 9157 to 14 411): 7247 in men and 4027 in women. The article gives the projection period as 2013-2029 in its abstract and discussion, but as 2012-2030 in this sentence of the results.
  • The authors found no statistical evidence of different time patterns between men and women.
• The authors' conclusion: The authors concluded that mesothelioma was still increasing in Lombardy, reflecting extensive past occupational (mainly in men) and non-occupational (mainly in women) asbestos exposure. They noted that, unlike in countries where men predominated, the number of affected women was quite large.
• Limitations the authors state:
  • Failure to identify exposure at interview may reflect that interviews are an incomplete tool, for example because people may not know asbestos was present at their workplace.
  • The analyses split by occupational versus non-occupational exposure cannot be read as absolute rates, because population denominators were not stratified by exposure.
  • The projections used Poisson age-cohort models, partly because information on past asbestos use in Lombardy was lacking. The authors noted that other researchers have reported that such models may overestimate future burden.
  • Effects of environmental asbestos exposure are especially difficult to study.

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: Mesothelioma, Occupational Exposure, Non-Occupational Exposure, Incidence.

Related studies

• Estimate of environmental and occupational components in the spatial distribution of malignant mesothelioma incidence in Lombardy (Italy) — D. Catelan, D. Consonni, et al. (2020)
• Past trends and future prediction of mesothelioma incidence in an industrialized area of Italy, the Veneto Region — P. Girardi, V. Bressan, et al. (2014)
• 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)
• Differences between peritoneal and pleural mesothelioma in Lombardy, Italy — C. Mensi, M. Mendola, et al. (2017)
• Time trend of mesothelioma incidence in the United States and projection of future cases: an update based on SEER data for 1973 through 2005 — B. Price, A. Ware (2009)

Browse more research in Occupational and Environmental Medicine, or return to medical research.