Radiological Features In Chrysotile Asbestos Mine And Mill Workers In Corsica

Our plain-English summary of Radiological Features In Chrysotile Asbestos Mine And Mill Workers In Corsica, by C. Boutin, J.R. Viallat, M. Bellenfant (1980).

The study

• Authors: C. Boutin, J.R. Viallat, M. Bellenfant
• Published: Biological Effects Of Mineral Fibres (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 30, Pp. 507-511 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 002174. The article is still under copyright, so we describe it here rather than post it.

In plain English

This report described chest X-ray findings in former workers of the chrysotile asbestos mine and mill at Canari, Corsica, which operated from 1948 to 1965. The authors had followed 240 ex-workers since 1975. Here they reported X-rays of 166 whose work exposure ended when the mine closed, 14 years earlier. On average, the workers had been exposed for 11.3 years to relatively pure chrysotile ore, at very high dust levels (85 to 267 million particles per cubic foot). The authors multiplied years of exposure by dust-level ratings to give a 'dust-weighted-time exposure'. Overall, 47% of the workers had abnormal X-rays. 19.3% had lung scarring (parenchymal fibrosis) only, 6.6% had pleural changes on both sides (thickening or plaques), and the rest of the 47% had both. One-sided pleural changes did not differ significantly between the workers and a control group. Years of exposure did not correlate with severity, except for the normal-X-ray group. Dust-weighted-time exposure correlated fairly well with severity of fibrosis and with pleural changes on both sides. The workers with severe lesions were slightly but significantly older. The authors concluded that the data indicate the importance of dust concentration in causing asbestos-related disorders.

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: Radiological (chest X-ray) survey of a followed group of former mine and mill workers, with comparison to a control group
• Who was studied: Former workers of the Canari chrysotile mine and mill in Corsica (open 1948 to 1965). 240 ex-workers were followed since 1975. X-ray results were reported for 166 whose occupational exposure ended at the mine closure, 14 years earlier. Mean time since first exposure was 24.6 years.
• Exposure: Relatively pure chrysotile ore, for a mean of 11.3 years, at very high dust levels of 85 to 267 million particles per cubic foot (mppcf). Exposure was also expressed as a dust-weighted-time exposure: time of exposure multiplied by risk indices ranging from 0.5 to 6 according to dust level.
• Main results:
  • Among the ex-workers, 19.3% had isolated parenchymal fibrosis (grade 1/1 or more).
  • Among the ex-workers, 6.6% had bilateral pleural changes (thickening or plaques).
  • A further share of the ex-workers had both types of abnormality. The scanned text prints this figure as '21.12'. Subtracting 19.3% and 6.6% from the article's stated 47% total abnormal gives 21.1%, but that is a calculation, not a figure the readable text prints.
  • In total, 47% of the workers had abnormal X-ray features. The OCR prints '472'; the French résumé gives 47%.
  • The percentage of unilateral pleural changes did not differ significantly between asbestos-exposed subjects and the control group. The authors said such changes should not be considered indicators of asbestos exposure.
  • Time of exposure was relatively homogeneous (mean 11.3 years). It did not correlate with severity of radiological changes, except for the 'normal' subclass.
  • Dust-weighted-time exposure correlated fairly well with the severity of fibrosis and with bilateral pleural lesions.
  • Age (mean 55.6) was slightly but significantly (P < 0.01) higher in the group with severe lesions.
  • Bilateral pleural changes was the most discriminating parameter for parenchymal changes, followed by dust-weighted-time exposure.
• The authors' conclusion: The authors concluded that, since age, tobacco consumption and length of exposure were similar in all the workers, the data indicate the importance of dust concentration in the induction of asbestos-related disorders.

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile, Chest X-Ray, Million Particles per Cubic Foot (mppcf), Interstitial Fibrosis, Fibrosis.

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