Asbestos exposure and benign asbestos diseases in 772 formerly exposed workers: dose-response relationships

Our plain-English summary of Asbestos exposure and benign asbestos diseases in 772 formerly exposed workers: dose-response relationships, by G. Mastrangelo, M.N. Ballarin, E. Bellini, et al (American Journal of Industrial Medicine, 2009).

The study

• Authors: G. Mastrangelo, M.N. Ballarin, E. Bellini, F. Bicciato, F. Zannol, F. Gioffrè, A. Zedde, G. Tessadri, U. Fedeli, F. Valentini, L. Scoizzato, G. Marangi, J.H. Lange
• Journal: American Journal of Industrial Medicine
• Published: 2009;52(8):596-602
• Cited by: 30 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Since previous studies have provided conflicting results, we investigated the relationship between the risk of benign asbestos-related diseases and different aspects of asbestos exposure in previous asbestos workers who underwent low-dose computed tomography (CT).

Methods: CT scans were carried out in 772 subjects. A questionnaire was employed to collect data on smoking habits and duration, peak and cumulative exposure, and time since first exposure to asbestos. Multiple logistic regression models with stepwise selection of variables were used to evaluate the associations.

Results: Fourteen (1.8%) cases of asbestosis, 187 (24.2%) of pleural plaques (PP), and 50 (6.5%) of diffuse pleural thickening (DPT) were found. The significant risk factors were: cumulative exposure for asbestosis (P for trend = 0.004); time since first exposure (P for trend <0.001), and peak exposure (P for trend <0.001) for PP; and time since first exposure for DPT (P for trend = 0.024).

Conclusions: Parenchymal asbestosis and PP are associated with different aspects of asbestos exposure. DPT appears to be less specific for asbestos exposure.

In plain English

This Italian study examined 772 men who formerly worked in asbestos-cement manufacturing, railway rolling stock fabrication and repair, or as insulators in shipyards or elsewhere. They had low-dose CT scans from 2000 to 2003 in a Veneto Region surveillance program. Past exposure was estimated by questionnaire, and the article does not name these workers' fiber types. Scans showed asbestosis in 14 men (1.8%), pleural plaques in 187 (24.2%) and diffuse pleural thickening in 50 (6.5%). Asbestosis risk increased significantly with cumulative exposure (P for trend 0.004). No statistically significant increase was found with peak exposure, time since first exposure, duration, age or smoking. Pleural plaques were linked to peak exposure and time since first exposure. In the final model, the highest peak-exposure group (above 13.5 fibers/ml) had a prevalence ratio of 3.12 (95% CI 1.54 to 6.32) compared with the lowest group. Diffuse pleural thickening showed one statistically significant finding: a rising trend with time since first exposure (P for trend 0.024). The authors concluded that diffuse pleural thickening is less specific for asbestos exposure. They noted that exposure was estimated retrospectively.

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: Cross-sectional analysis of low-dose CT findings and questionnaire-based exposure estimates, collected in a post-occupational medical surveillance program
• Who was studied: 772 male former asbestos workers in the Veneto Region, Italy, examined from 2000 to 2003. They had worked in asbestos-cement manufacture, railway rolling stock fabrication and repair, or as insulators in shipyards or elsewhere.
• Exposure: Occupational asbestos exposure. The fiber types these workers were exposed to are not specified. Exposure was estimated with a job-specific questionnaire. The measures were cumulative exposure (fibers/ml times years), peak exposure, duration of exposure and time since first exposure.
• Main results:
  • Among the 772 workers, CT showed asbestosis in 14 (1.8%), pleural plaques in 187 (24.2%) and diffuse pleural thickening in 50 (6.5%).
  • Asbestosis risk increased significantly with cumulative exposure (trend test P 0.004). No significant increase was found with time since first exposure, peak exposure, duration of exposure, age or smoking.
  • The lowest cumulative exposure in any worker with asbestosis was 23.1 fibers/ml times years.
  • For pleural plaques, the final log-binomial model found significant effects of peak exposure and time since first exposure, with a steady rise in risk only with peak exposure. The highest peak-exposure group (above 13.5 fibers/ml) had a prevalence ratio of 3.12 (95% CI 1.54 to 6.32) compared with the group below 1.35 fibers/ml. Smoking and age did not confound these associations.
  • For diffuse pleural thickening, the only statistically significant finding was an increasing trend with time since first exposure (P for trend 0.024). No variable entered the final log-binomial model.
• The authors' conclusion: The authors concluded that asbestosis and pleural plaques are associated with different aspects of asbestos exposure. They concluded that diffuse pleural thickening is less specific for asbestos exposure and requires accurate differential diagnosis.
• Limitations the authors state:
  • Exposure was assessed retrospectively, because measured exposure data were not available except in two plants.
  • With the job-specific module approach, agreement among experts may be poor.
  • The quality of the job information varied between workers.
  • Interviews took more than an hour, causing discomfort to interviewees, who were often elderly.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Dose-response relationship, Low-Dose CT Screening, CT Scan, Habit, Cumulative Exposure, Pleural Plaques, Diffuse Pleural Thickening.

Related studies

• Chest pain in asbestos-exposed individuals with benign pleural and parenchymal disease — S. Mukherjee, N. de Klerk, et al. (2000)
• Pleural plaques and asbestosis: dose- and time-response relationships based on HRCT data — C. Paris, S. Thierry, et al. (2009)
• A study of dose-response relationships for asbestos associated disease — M.M. Finkelstein (1985)
• Asbestos-related diseases in automobile mechanics — J. Ameille, N. Rosenberg, et al. (2012)
• Feasibility of a screening programme for lung cancer in former asbestos workers — G. Mastrangelo, M.N. Ballarin, et al. (2008)
• Relationships between asbestos exposure and pleural plaques: dose and time effects using fractional polynomials — M. Menant, I. Benlala, et al. (2024)

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