Overstating the consequences of radiographic abnormalities

Our plain-English summary of Overstating the consequences of radiographic abnormalities, by J.J. Flynn, S. Kardos, L. Yan (Environmental Health Perspectives, 2004).

The study

• Authors: J.J. Flynn, S. Kardos, L. Yan
• Journal: Environmental Health Perspectives
• Published: 2004;112(2):A84; author reply A84-5
• Type of article: Letter, Comment
• Read it: PubMed · Publisher · Free full text

In plain English

This item is a letter to the editor, with a reply, about a 2003 study by Peipins and colleagues of chest X-ray abnormalities in Libby, Montana, a community exposed to asbestos-contaminated vermiculite. The letter's authors work for Health Network America, which administers the Libby Medical Plan. They described preliminary observations from an ongoing review of plan applicants and members. They argued that the X-ray readers knew the films came from Libby, that the third reader saw the first two readers' reports, and that no control films were used. They also said that differing findings by two readers were apparently counted as agreement. They reported that 89% of 341 plan participants were overweight and 54% obese. In many cases, they said, people coded positive showed no visible asbestos-related changes. They concluded the study markedly overstated the consequences of exposure. In reply, the study authors reported that pleural abnormalities rose from 6.7% of people with no apparent exposure to 23.7% of those reporting six or more exposure pathways, a trend still present after controlling for body mass. CT scans found pleural abnormalities in 98 of 353 people (28%) whose X-rays were indeterminate. The study authors suggested their estimates may be conservative.

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 (correspondence) criticizing a published study, followed by the original study authors' reply; the letter writers are employees of Health Network America, the administrator of the Libby Medical Plan
• Who was studied: Applicants to and members of the Libby Medical Plan whose X-rays and CT scans were peer reviewed by Health Network America; body mass index data for 341 of them. The reply adds CT results for 353 Libby medical screening participants with indeterminate chest X-rays.
• Exposure: Asbestos-contaminated vermiculite in the community of Libby, Montana, as studied by Peipins et al. (2003)
• Main results:
  • Letter writers: all B-readers (certified X-ray readers) in the Peipins study knew the films were from Libby residents, which the writers said opened the door to reader bias
  • Letter writers: the third B-reader had the first two readers' reports before making an interpretation
  • Letter writers: no control films or control group were used
  • Letter writers: according to their unpublished review, readings by two readers that described findings in different locations were apparently recorded as a positive finding by two B-readers
  • Letter writers: among 341 Libby Medical Plan participants, 89% were overweight and 54% were obese. By body mass index: 23 (7%) were 40 or higher, 160 (47%) were 30 to 39.9, 120 (35%) were 25 to 29.9, and 38 (11%) were under 25.
  • Letter writers: in their continuing review, in many cases participants coded as positive for pleural changes had no visible asbestos-related changes on their X-rays, or had subpleural fat misread as pleural thickening or plaques
  • Reply: the B-readers were blinded to the identities of the people screened
  • Reply: pleural abnormalities were found in 6.7% of the group with no apparent exposure, 10.8% of those reporting one to three exposure pathways, 14.4% of those reporting four to five, and 23.7% of those reporting six or more
  • Reply: this trend remained significant after controlling for body mass index in the multivariate analysis
  • Reply: high-resolution CT scans of 353 Libby screening participants with indeterminate chest X-rays (only one of three B-readers noted an abnormality) found pleural abnormalities in 98 persons (28% of those tested)
  • Reply: the study authors suggested their estimates of pleural abnormalities may be conservative
• The authors' conclusion: The letter writers concluded that, because of study bias, inconsistent B-reader reports and failure to account for high body mass and pleural fat, the Peipins et al. study markedly overstated the consequences of asbestos exposure in Libby. The study authors disagreed in their reply.
• Limitations the authors state:
  • Letter writers: their review was still ongoing and their observations were preliminary
  • Reply: the CT results were preliminary data

Topics

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

Related studies

• Radiographic abnormalities and asbestos exposure: Libby, Montana — B. Price (2004)
• Radiographic abnormalities and exposure to asbestos-contaminated vermiculite in the community of Libby, Montana, USA — L.A. Peipins, M. Lewin, et al. (2003)
• Impact of body mass index on the detection of radiographic localized pleural thickening — T.C. Larson, A. Franzblau, et al. (2014)
• The radiographic pleural abnormalities in asbestos exposure: relationship to physiologic abnormalities — R.N. Jones, T. McLoud, et al. (1988)
• Radiographic abnormalities and mortality in subjects with exposure to crocidolite — N.H. de Klerk, A.W. Musk, et al. (1993)
• The usefulness of computed tomography in detecting asbestos-related pleural abnormalities in people who had indeterminate chest radiographs: the Libby, MT, experience — O.I. Muravov, W.E. Kaye, et al. (2005)

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