Mesothelioma continues to increase even 40 years after exposure - Evidence from long-term epidemiological observation

Our plain-English summary of Mesothelioma continues to increase even 40 years after exposure - Evidence from long-term epidemiological observation, by B. Świątkowska, N. Szeszenia-Dąbrowska (Lung Cancer, 2017).

The study

• Authors: B. Świątkowska, N. Szeszenia-Dąbrowska
• Journal: Lung Cancer
• Published: 2017;108:121-125
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Because asbestos dust is considered one of the most dangerous types of dust for people's health, issues related to the effects of asbestos exposure still remain questions about the role of cessation of exposure.

Objectives: The aim of the present study was to determine the importance of temporal patterns, especially the time since the end of exposure in the risk of pleural mesothelioma.

Methods: A total of 131 patients with pleural mesothelioma and 655 frequency matched by gender and year of birth controls enrolled in the health surveillance programme for asbestos-related diseases over the years 2000-2014, were included in the analysis. Conditional logistic regression models were applied to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results: The results show that the risk of pleural mesothelioma continued to increase even after 40 years since the last exposure. The estimated odds ratio for the subjects who had their last exposure 40 years ago, compared with the odds ratio of those who had their last exposure 5 years ago, was 2.68 (95%CI: 1.16-.621). We also observed that crocidolite exposure was associated with a very high significant mesothelioma risk, 5-fold higher for those working with mixed exposure compared to the subjects who worked only with chrysotile.

Conclusions: Dose-response relationships in populations occupationally exposed are critical to the study related to environment asbestos contamination. Our findings confirm the strong evidence that mesothelioma risk increases along with the increasing time since exposure termination.

Copyright © 2017 Elsevier B.V. All rights reserved.

In plain English

This Polish study compared 131 former asbestos-processing plant workers with pleural mesothelioma (95 men, 36 women) with 655 former workers without the disease, matched by gender, year of birth and vital status. All took part in the Amiantus health surveillance programme and were examined at least once between 2000 and 2014. Exposure to asbestos dust was estimated from 4000 workplace dust measurements taken from 1956 to 2000. In one statistical model, workers whose exposure had ended 40 years earlier had an odds ratio of 2.68 (95% CI 1.16 to 6.21) compared with workers whose exposure had ended 5 years earlier. In a second model, the odds ratios for time since last exposure were not statistically significant. Work with asbestos mixed with crocidolite, compared with chrysotile only, had an odds ratio of 5.07 (2.48 to 10.35). The highest cumulative exposure (100 mg/m3 x years), compared with none, had an odds ratio of 1.53 (0.83 to 2.80). The authors concluded that a mesothelioma effect may remain even 40 years after the last exposure, which calls for follow-up. They noted that participation was voluntary and that dust was measured by weight, not by fiber count.

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: Case-control study drawn from a surveillance cohort of former asbestos workers, with five controls per case, analysed by logistic regression
• Who was studied: Former workers of all former Polish asbestos processing plants in the Amiantus Programme, examined at least once in 2000 to 2014. There were 131 pleural mesothelioma cases (95 men, 36 women) and 655 controls (475 men, 180 women).
• Exposure: Occupational asbestos dust in plants making asbestos-cement, waterproofing, textiles, sealants, friction and other products. Exposure was estimated from gravimetric dust measurements (mg/m3) taken 1956 to 2000 and expressed as a cumulative exposure index and a mean exposure index. Workers were grouped as exposed to chrysotile only or to asbestos mixed with crocidolite.
• Main results:
  • Model 1: workers whose last exposure was 40 years earlier had an OR of 2.68 (95% CI 1.16 to 6.21) for pleural mesothelioma compared with those whose last exposure was 5 years earlier
  • Model 1: exposure to asbestos mixed with crocidolite, compared with chrysotile only, had an OR of 5.07 (95% CI 2.48 to 10.35)
  • Model 1: the highest cumulative exposure (100 mg/m3 x years), compared with unexposed, had an OR of 1.53 (95% CI 0.83 to 2.80)
  • Model 2: exposure to asbestos mixed with crocidolite, compared with chrysotile only, had an OR of 4.88 (95% CI 2.36 to 10.07)
  • Model 2: last exposure 10 and 40 years earlier gave ORs of 1.27 (0.90 to 1.80) and 3.46 (0.79 to 15.06); these ORs were not statistically significant
  • Model 2: exposure duration of 10 years gave an OR of 0.95 (0.51 to 1.80) and 40 years an OR of 2.79 (0.77 to 10.04)
• The authors' conclusion: The authors concluded that a mesothelioma effect may still be present even 40 years after the last exposure, and that this calls for continued follow-up of former asbestos workers
• Limitations the authors state:
  • The programme covers only former asbestos processing plant workers, participation was voluntary, and not everyone was willing to take part
  • Exposure was assessed from retrospective gravimetric dust measurements, so fiber counts could not be calculated or compared with current hygiene standards

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, Pleural Mesothelioma, Odds Ratio, confidence interval, Crocidolite, Chrysotile, Dose-response relationship.

Related studies

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• Long-term follow-up of a well-differentiated mesothelioma of the peritoneum in a 2-year-old girl — L. Wünsch, P. Flemming, et al. (1998)
• Australia's Ongoing Legacy of Asbestos: Significant Challenges Remain Even after the Complete Banning of Asbestos Almost Fifteen Years Ago — M. Soeberg, D.A. Vallance, et al. (2018)
• Long-term effects of carbon containing engineered nanomaterials and asbestos in the lung: one year postexposure comparisons — A.A. Shvedova, N. Yanamala, et al. (2014)

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