Follow-Up of the Libby, Montana Screening Cohort: A 17-Year Mortality Study: Likely Underestimation of Nonmalignant Asbestos-Related Disease

Our plain-English summary of Follow-Up of the Libby, Montana Screening Cohort: A 17-Year Mortality Study: Likely Underestimation of Nonmalignant Asbestos-Related Disease, by A. Miller, G.M. Loewen, J. Szeinuk (Journal of Occupational and Environmental Medicine, 2020).

The study

• Authors: A. Miller, G.M. Loewen, J. Szeinuk
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2020;62(5):e233-e234
• Type of article: Letter, Comment
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor, not a new study. The authors commented on a 17-year mortality study by Larson, Williamson and Antao of 8043 people screened for Libby amphibole (LA) disease. The letter noted that more than half (54%) of those screened were under 50. The authors argued that death certificates poorly record asbestosis, stating that they identified 201 of 427 (47%) asbestosis deaths in long-term insulators. The second signatory, who had practiced in Libby, stated that the medical records and death certificates of many local physicians did not note asbestos-related disease when it was clearly evident. That is the opposite of the bias Larson et al. had suggested. The letter added that many residents moved away, citing a report of pleural thickening in 48% of 198 people who left Libby after high school. It also said many death certificates in the Libby area were completed by non-physicians, including coroners and even undertakers. The authors argued that chest x-rays miss disease, citing the first signatory's study of 2760 atomic weapons workers. In that study, CT found pleural thickening in 271, and x-ray film showed only 54 of them. The authors concluded that nonmalignant asbestos-related deaths in Libby were greatly underestimated.

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: Letter to the editor commenting on a published mortality study (Larson et al.); no new data collected
• Who was studied: No new population studied; the letter discusses the 8043 people screened in Lincoln County and elsewhere in the United States in the Larson et al. 17-year mortality study
• Exposure: Libby amphibole (LA), from occupational, household and community exposure in the Libby, Montana area
• Main results:
  • The letter states that the 8043 people screened by Larson et al. were slightly more than 10% of an estimated 70,000 who lived in the area, and more than half (54%) were under 50 years of age and therefore less likely to show asbestos-related disease
  • The letter states that death certificates identified less than half of asbestosis deaths (47%, or 201 of 427) in long-term insulators
  • The second signatory, who had practiced in Libby, stated that the medical records and death certificates of many physicians in the community did not note asbestos-related disease when it was clearly evident. Larson et al. had suggested the opposite bias: certifiers being overly aware of asbestos-related disease
  • The letter cites a recent publication reporting asbestos-related pleural thickening in almost half (48%) of 198 persons who left Libby on graduating from high school. It argues that deaths among people who moved away would not be certified by doctors aware of asbestos-related disease
  • The letter states that many death certificates in the Libby area were completed by non-physicians, including coroners and undertakers
  • Citing the first signatory's earlier study of 2760 atomic weapons workers potentially exposed to asbestos: CT showed pleural thickening in 271 (9.8%), and only 54 of them (20%) showed it on x-ray film
  • In the same cited study, interstitial opacities were seen on 76 CT scans (2.8% of those examined), and only 10 of them (13%) were identified on x-ray film
• The authors' conclusion: The authors concluded that the frequency of nonmalignant asbestos-related deaths in the Libby population reported by Larson et al. is greatly underestimated. They called for a mortality study covering all routes of exposure that uses death certificates, best-evidence review, CT scans and x-ray film

Topics

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

Related studies

• Response to 'Follow-Up of the Libby, Montana Screening Cohort: A 17-year Mortality Study: Likely Underestimation of Nonmalignant Asbestos-Related Disease' — T.C. Larson, L. Williamson, et al. (2020)
• Follow-Up of the Libby, Montana Screening Cohort: A 17-Year Mortality Study — T.C. Larson, L. Williamson, et al. (2020)
• Vermiculite, respiratory disease, and asbestos exposure in Libby, Montana: update of a cohort mortality study — P.A. Sullivan (2007)
• Mortality in a cohort of vermiculite miners exposed to fibrous amphibole in Libby, Montana — J.C. McDonald, J. Harris, et al. (2004)
• Asbestos-related pleural disease due to tremolite associated with progressive loss of lung function: serial observations in 123 miners, family members, and residents of Libby, Montana — A.C. Whitehouse (2004)
• Lung function predicts mortality: 10-year follow-up after lung cancer screening among asbestos-exposed workers — T. Vehmas, P. Pallasaho, et al. (2013)

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