Asbestos-related radiographic changes by ILO classification of 10 x 10 cm chest X-rays in a screening of the general population

Our plain-English summary of Asbestos-related radiographic changes by ILO classification of 10 x 10 cm chest X-rays in a screening of the general population, by B. Hilt, G. Hillerdal, P.G. Lund-Larsen, et al (Journal of Occupational and Environmental Medicine, 1995).

The study

• Authors: B. Hilt, G. Hillerdal, P.G. Lund-Larsen, J.T. Lien, S. Langård
• Journal: Journal of Occupational and Environmental Medicine
• Published: 1995;37(2):189-93
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A sample of 1388 10 x 10 cm chest X-rays from a previous population screening of males aged 40+ years were reevaluated by use of the ILO classification. There were 1036 films of subjects from an industrialized town, and 352 from a rural community. The observed rates of parenchymal changes (profusion > or = 1/0) at the reevaluation were 1.3% in the urban community and 3.4% in the rural community. The corresponding figures for pleural changes were 5.0% and 0.6%, respectively. Based on additional questionnaire information on asbestos exposure, it was found that the radiographic changes were probably related to past asbestos exposure for 2.3% of the subjects from the urban community and 0.6% from the rural community. In cases of asbestos-related illnesses the mean time since first exposure to asbestos was 35.9 years, whereas the mean duration of the exposures was 11.4 years. The results seem to indicate that the ILO reassessment of the radiographs was more sensitive in detecting pleural changes than the previous clinical screening of both small and large films.

In plain English

The authors re-read a sample of 1388 small (10 × 10 cm) chest X-rays from an earlier screening of men aged 40 and over in Telemark county, Norway. Of these, 1036 came from an industrial town and 352 from a rural community. One experienced reader, who did not know where the films came from or the men's exposure, used the ILO classification. Lung-tissue changes (small opacities, profusion 1/0 or more) were seen in 1.3% of urban and 3.4% of rural men, and pleural changes in 5.0% and 0.6%. Where a questionnaire also confirmed past work exposure to asbestos, changes were judged probably asbestos-related: 2.3% of urban and 0.6% of rural men. The lung-tissue changes showed no clear link to work exposure. Among men examined clinically earlier, the ILO reading found pleural changes in 24 of 29 with pleural plaques but small opacities in only 1 of 4 with asbestosis. The authors concluded the ILO reading was more sensitive for pleural changes than the earlier screening. They said the questionnaire's low sensitivity limited detection of asbestos-related illness.

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: Re-evaluation, using the ILO classification, of chest X-rays taken in an earlier cross-sectional population screening; films read by one reader without knowledge of their origin or the subjects' exposure
• Who was studied: 1388 men aged 40 and over from an earlier screening in Telemark county, Norway: 1036 from the industrial town of Porsgrunn (urban) and 352 from the rural municipality of Seljord. Mean ages were 59.4 (SD 11.1) years urban and 62.8 (SD 11.8) years rural.
• Exposure: Work-related asbestos exposure as confirmed in a questionnaire from the primary screening, reported by 22.1% of urban and 5.7% of rural participants. No fiber types are named.
• Main results:
  • Among all 1388 men, 75 (5.4%) had some finding described on ILO reading.
  • Small opacities with profusion 1/0 or more were seen in 13 (1.3%) urban men and 12 (3.4%) rural men (P < 0.05).
  • Any pleural changes were seen in 52 (5.0%) urban men and 2 (0.6%) rural men (P < 0.01).
  • Combining ILO findings with questionnaire-confirmed exposure, findings were judged probably asbestos-related in 2.3% of urban and 0.6% of rural men.
  • The authors found no clear relation between the observed parenchymal (lung-tissue) changes and work-related exposures.
  • In cases of asbestos-related illness, the mean time since first exposure to asbestos was 35.9 years.
  • In cases of asbestos-related illness, the mean duration of exposure was 11.4 years.
  • Among 29 men diagnosed with pleural plaques at an earlier clinical examination using large films, the ILO reading found pleural changes in 24 (82.8%).
  • Among 4 men previously diagnosed with pulmonary asbestosis, the ILO reading found small opacities with profusion 1/0 or more in only one.
  • When ILO findings were combined with questionnaire exposure information, only 16 of the 30 previously diagnosed men (53.3%) were classified as having an asbestos-related illness.
• The authors' conclusion: The authors concluded that the results seem to indicate that the ILO reassessment of the small films was more sensitive in detecting pleural changes than the previous clinical screening of both small and large films.
• Limitations the authors state:
  • The authors stated that the main limiting factor in identifying asbestos-related illness, particularly pleural changes, was the low sensitivity of the questionnaire in detecting exposed subjects. The sensitivity was 44.6% in the earlier study.
  • The ILO scale for small opacities requires comparison with standard films that exist only in large sizes. The authors suggested this could be one reason why their reading was not very sensitive to asbestos-related lung-tissue changes.
  • The ILO classification cannot firmly separate extrapleural fat from diffuse pleural thickening, or large plaques from diffuse thickening.

Topics

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

Medical terms in this study, explained in our Lexicon: ILO Classification, Chest X-Ray, Asbestos Exposure.

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