An Attempt To Determine A Medium-Term, Low-Dose Asbestos Exposure Indicator On The Basis Of Clinical And Radiological Long Changes

Our plain-English summary of An Attempt To Determine A Medium-Term, Low-Dose Asbestos Exposure Indicator On The Basis Of Clinical And Radiological Long Changes, by L. Awad, P. Lazar, L. Di Menza, et al (1980).

The study

• Authors: L. Awad, P. Lazar, L. Di Menza, J. Bignon, G. Bonnaud
• Published: Biological Effects Of Mineral Fibres (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 30, Pp.755-761 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 004386. The article is still under copyright, so we describe it here rather than post it.

In plain English

This Paris study compared three groups of people whose exposure was linked to buildings with insufficient protection against asbestos sources such as ceilings, lagging and cupboards. Group 1 (160 people) repaired these sources or cleaned areas with obviously higher levels. Group 2 (277 people) had worked at least 10 years in such buildings without specific exposure. Group 3 (157 people), considered a control group, was exposed only during construction 15 years earlier and now worked in a building not treated with asbestos. No fiber type is named. Examining physicians did not know each person's group. Clinical examination showed no differences between groups. Diaphragmatic straightness on X-rays affected 12% of Group 1 versus 6% of Groups 2 and 3 (P = 0.05). Cough, sputum and breathlessness were more frequent in Group 1. Chest pain was more frequent in Groups 1 and 2. After adjusting for smoking, obesity, past and present asbestos exposure, age and sex, Group 1's differences remained significant. No relationship with time spent in the buildings was found. The authors concluded that the link with exposure level or duration was not clear enough.

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: Cross-sectional comparison of three groups using medical and radiological examinations and a questionnaire, with examiners who did not know each person's group
• Who was studied: Three groups of people in Paris. Group 1 had 160 people (mean age 41 years, 57% male) who worked in buildings with insufficient protection against asbestos. Group 2 had 277 people (mean age 41 years, 52% male) who had worked at least 10 years in such buildings. Group 3 had 157 people (mean age 45 years, 32% male) and was considered a control group; they now worked in a nonasbestos-treated building. No study dates are given.
• Exposure: Asbestos in buildings (ceilings, lagging, cupboards, etc.). Group 1 worked in direct contact with the sources, either repairing them or cleaning places with obviously higher levels. Group 2 had worked at least 10 years in such buildings with no specific exposure. Group 3 was exposed only during construction 15 years earlier and now worked in a nonasbestos-treated building. No fiber type and no measured doses are given.
• Main results:
  • Clinical examination showed no differences between the three groups.
  • Functional and radiological examinations showed significant differences. Cough, sputum, breathlessness and diaphragmatic straightness were more frequent in Group 1, and chest pain was more frequent in Groups 1 and 2.
  • Diaphragmatic straightness on X-ray was found in 12% of Group 1, 6% of Group 2 and 6% of Group 3 (P = 0.05). The average number of radiological abnormalities was 0.13, 0.07 and 0.05 respectively (P = 0.05).
  • Group 2 differed significantly from Group 3 only for chest pain.
  • Possible previous exposure to asbestos was much more frequent in Group 1 (29%) than in Group 2 (8%) or Group 3 (9%).
  • After adjusting for smoking, obesity, past and present asbestos exposure, age and sex, the differences between Group 1 and the other groups remained significant.
  • No relationship was found between any of the anomalies and the length of exposure, measured as the duration of presence in the buildings.
• The authors' conclusion: The authors concluded that significant differences in functional and radiological lung anomalies were shown between the more heavily exposed group and the other two, but that the relationship with level or duration of exposure was not clear enough (the rest of the sentence is cut off). They also suggested a probable interpretation: the light exposure of Group 2 had little or no effect, while the heavier exposure of Group 1 led to a significant increase in lung anomalies.
• Limitations the authors state:
  • Obesity, which was more common in Group 1 (44%), might explain some of the functional anomalies in that group.
  • Age and sex distributions differed between groups: Group 3 was older and contained more women.
  • The relationship with the level or duration of exposure was not clear enough to decide what weight to give each finding.
  • Results were reported only when the overall proportion of positive cases was at least 2%, a limit the authors chose arbitrarily.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Sputum.

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