Response to '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 Response to 'Follow-Up of the Libby, Montana Screening Cohort: A 17-year Mortality Study: Likely Underestimation of Nonmalignant Asbestos-Related Disease', by T.C. Larson, L. Williamson, V.C. Antao (Journal of Occupational and Environmental Medicine, 2020).

The study

• Authors: T.C. Larson, L. Williamson, V.C. Antao
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2020;62(5):e235
• Type of article: Letter, Comment
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

In plain English

This is not a new study. It is a short reply letter from the authors of a 2020 mortality study of people screened for asbestos-related disease in Libby, Montana, answering comments from Drs Miller, Loewen, Szeinuk, and Noonan. It reports no new data. The authors agreed that local physicians may not have noted asbestos-related disease in this cohort of screening participants, which could have led to under-counting of non-cancer asbestos-related deaths. They restated figures from their earlier paper: standardized mortality ratios (SMRs) for asbestosis ranged from 82, among workers in an 'other asbestos occupation' category, to 558, among household contacts, compared with a national reference population. They wrote that these indicate a striking excess. They also agreed that their results represent only screening participants. They explained that CT scans were not used because CT data were unavailable for most of the cohort. They noted that more than half the cohort was under 50 when screened. The authors concluded that continued monitoring of Libby residents and further mortality updates should be considered.

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 (the authors' reply to comments on their own earlier mortality study); no new data or analysis
• Who was studied: Refers to participants in the Agency for Toxic Substances and Disease Registry and Montana Department of Public Health and Human Services screening programs for current and former Libby, Montana residents. More than 50% were younger than 50 at screening. No new population was studied.
• Exposure: Libby amphibole asbestos from the Libby vermiculite operation
• Main results:
  • Restated from the authors' earlier 2020 publication, not new findings: asbestosis SMRs ranged from 82 (workers categorized as 'other asbestos occupation') to 558 (household contacts), compared with a national reference population
  • The authors stated that these SMRs indicate a striking excess of nonmalignant asbestos-related disease in the screening cohort
• The authors' conclusion: The authors concluded that continued monitoring of Libby residents and further mortality updates should be considered to detect trends in asbestos-related disease, because much of the cohort may have been too young at screening to have developed it
• Limitations the authors state:
  • Local physicians may not have noted asbestos-related disease in this cohort of screening participants, possibly leading to under-counting of nonmalignant asbestos-related mortality
  • Results represent only screening program participants. Other people exposed to Libby amphibole asbestos likely did not take part, possibly because they moved away from Libby or for other reasons.
  • CT scans, which are more sensitive than chest radiographs, were not used because CT data were unavailable for most of the cohort
  • Much of the cohort may have been too young to have developed asbestos-related disease

Topics

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

Related studies

• Follow-Up of the Libby, Montana Screening Cohort: A 17-Year Mortality Study: Likely Underestimation of Nonmalignant Asbestos-Related Disease — A. Miller, G.M. Loewen, 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)

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