Development of radiographic abnormality in chrysotile miners and millers

Our plain-English summary of Development of radiographic abnormality in chrysotile miners and millers, by G.M. Eyssen (Chest, 1980).

The study

• Author: G.M. Eyssen
• Journal: Chest
• Published: 1980;78(2 Suppl):411-4
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000801).

In plain English

This study examined chest X-rays of 270 men in Quebec who had worked wholly or mainly in chrysotile asbestos mining and milling. They were drawn by stratified random sampling from more than 11,000 men studied earlier. For each man, the most recent film up to 1971 and four earlier films taken about five years apart were read side by side, in time order, by five readers from four countries, using an extended form of the ILO U/C 1971 classification. The aim was to describe the first film each reader judged abnormal. The readers differed greatly. The share of men judged normal on the first film ranged from 53 to 97 percent. Among those men, the share with a later film judged abnormal ranged from 24 to 96 percent. Readers agreed that the first abnormal film usually showed small opacities, pleural thickening of the chest wall, or both, and that large opacities were never seen. They disagreed on the shape, lung zone and side of the changes. The author noted that the study's methods may have added to this disagreement. The author concluded that observer variability must be controlled and accounted for in such studies.

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: Analysis of serial chest radiographs taken from an earlier epidemiologic study. Five readers assessed each man's set of five films side by side, in known time order, to describe the first radiographic abnormality.
• Who was studied: 270 men who had worked wholly or predominantly in chrysotile mining and milling in the Quebec asbestos-producing industry (Asbestos and Thetford Mines). They were selected by stratified random sampling (about 300 men selected) from over 11,000 men whose films up to 1966 had been studied earlier. Films were included up to 1971.
• Exposure: Employment in chrysotile asbestos mining and milling in Quebec. No exposure doses are analyzed in this report.
• Main results:
  • The proportion of subjects judged 'normal' on the first film (and so eligible to show a new abnormality) varied by reader from 53 percent to 97 percent.
  • Among the men eligible, the proportion whose later film was judged abnormal ('attacked') ranged from 24 percent to 96 percent, depending on the reader.
  • All readers agreed that the first abnormal film usually showed small opacities, pleural thickening of the chest wall, or both.
  • Large opacities were never seen in the first abnormal film. An ill-defined diaphragm or cardiac outline was rare.
  • When small opacities were recorded, three readers found rounded and irregular shapes roughly equally common. The other two readers recorded mostly irregular opacities.
  • Readers differed on the size of opacities but agreed that the largest sizes (types r and u) seldom occurred.
  • Only reader D reported the conventional preponderance of rounded opacities in the upper lung zones. Irregular opacities showed a slight tendency to be recorded less often in the upper zones.
  • Readers disagreed on the side of pleural thickening in the first abnormal film. Readers B and E usually recorded the left side, readers C and D the right side, and reader A left, right and both sides equally.
• The authors' conclusion: The author found little consistency among the readers. Because reading chest radiographs is subjective, the author concluded that epidemiologic studies must try to control observer variability (a clear reading objective, reader training, standard films) and must take it into account when interpreting findings. The author also stated that the chest radiograph is only one tool for diagnosing asbestosis.
• Limitations the authors state:
  • The new elaborated scales of abnormality may have contributed to the variation between readers.
  • Describing early radiographic changes was not the primary objective of the reading, and the reading instructions were general.

Topics

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

Medical terms in this study, explained in our Lexicon: Chrysotile.

Related studies

• Radiographic changes in a group of chrysotile miners and millers exposed to low asbestos dust concentrations — S. Cordier, G. Theriault, et al. (1984)
• 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)
• Prevalence of radiographic asbestosis in crocidolite miners and millers at Wittenoom, Western Australia — W.O. Cookson, N.H. De Klerk, et al. (1986)
• The 1891-1920 birth cohort of Quebec chrysotile miners and millers: development from 1904 and mortality to 1992 — F.D. Liddell, A.D. McDonald, et al. (1997)
• Lung function and radiographic change in chrysotile workers in Swaziland — M. McDermott, M.M. Bevan, et al. (1982)
• The 1891-1920 birth cohort of Quebec chrysotile miners and millers: mortality 1976-88 — J.C. McDonald, F.D. Liddell, et al. (1993)

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