Asbestos findings questioned

Our plain-English summary of Asbestos findings questioned, by J.B. Gee (Environmental Health Perspectives, 1993).

The study

• Author: J.B. Gee
• Journal: Environmental Health Perspectives
• Published: 1993;101(7):564-5
• Type of article: Comment, Letter
• Read it: PubMed · Publisher · Free full text

In plain English

This item is not a research study. It is a letter to the editor by J. Bernad Gee of Yale University questioning a 1993 review by A.R. Brody on asbestos-induced lung disease, followed by Brody's reply. The letter author described Brody's earlier experiment, in which rats inhaled chrysotile asbestos at several million fibers per liter of air. In that experiment the percentages of radiolabeled epithelial and interstitial cells rose fourfold between 12 and 48 hours after exposure, and normal labeling returned by 8 days. The letter author argued that these levels were far above those of building occupants, citing a report that such people had been exposed to less than 1 fiber per liter of air. In the letter author's view, the real news was the effectiveness of the lung's defenses. In reply, Brody acknowledged that animal analogies are often problematic. Brody stated, however, that the brief cell proliferation goes on to produce a scar that persists for at least six months after a brief exposure. Neither part reported new data. The available text ends mid-sentence.

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 criticizing a published review, with the review author's response; no new study
• Who was studied: No population was studied in this letter. It discusses rats used in Brody's earlier inhalation experiments and people in buildings, as described in other publications.
• Exposure: Chrysotile asbestos inhaled by rats at several million fibers per liter of air, in Brody's earlier experiments discussed in the letter
• Main results:
  • The letter author described Brody's earlier rat experiment: there were fourfold increases in the percentages of radiolabeled epithelial and interstitial cells between 12 and 48 hours after exposure. These are Brody's findings, not this letter's.
  • According to the letter author's account of Brody's experiment, normal labeling returned by 8 days after exposure and was maintained through 1 month.
  • The letter author cited a Health Effects Institute report that local inhabitants of buildings had been shown to be exposed to levels less than 1 fiber per liter of air.
  • The letter author argued that the notable finding was the effectiveness of the rats' lung defenses, not the transient cell response.
  • In reply, Brody stated that the animals are exposed to high concentrations of fibers for brief periods, from one hour to three days.
  • In reply, Brody stated that the transient cell proliferation goes on to result in a scar that persists for at least six months after a brief exposure.
  • In reply, Brody stated that people in buildings with asbestos-containing materials would be exposed to much lower concentrations of fibers, but possibly for longer periods and more frequently than the experimental animals.
• The authors' conclusion: The letter author concluded that Brody had missed the point of Brody's own work, which in the letter author's view showed how well the lung defends itself.
• Limitations the authors state:
  • In reply, Brody acknowledged that using animals as analogues for human exposure is often problematic.
  • Brody acknowledged that it is not known how many fibers reach the alveolar and pleural surfaces of exposed humans.

Related studies

• Sequence of bronchoalveolar lavage and histopathologic findings in rat lungs early in inhalation asbestos exposure — C.M. Smith, S. Batcher, et al. (1987)
• Scientific method questioned — D.J. Paustenbach (2006)
• Radiological findings as predictors of mortality in Quebec asbestos workers — F.D. Liddell, J.C. McDonald (1980)
• The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part III. Radiographic findings — H.E. Amandus, R. Althouse, et al. (1987)
• Biopersistence of cerium in the human respiratory tract and ultrastructural findings — J.C. Pairon, F. Roos, et al. (1995)
• Findings from high resolution computed tomography of the lung and pleura of symptom free workers exposed to amosite who had normal chest radiographs and pulmonary function tests — S. Neri, A. Antonelli, et al. (1994)

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