Asbestos exposure and radiological abnormalities among maintenance and custodian workers in buildings with friable asbestos-containing materials

Our plain-English summary of Asbestos exposure and radiological abnormalities among maintenance and custodian workers in buildings with friable asbestos-containing materials, by M. Matrat, J.C. Pairon, A.G. Paolillo, et al (International Archives of Occupational and Environmental Health, 2004).

The study

• Authors: M. Matrat, J.C. Pairon, A.G. Paolillo, N. Joly, Y. Iwatsubo, E. Orlowski, M. Letourneux, J. Ameille
• Journal: International Archives of Occupational and Environmental Health
• Published: 2004;77(5):307-12
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: Few studies have been carried out to evaluate the respiratory effects of asbestos exposure of custodian and maintenance workers.

Methods: By a multicentre cross-sectional study, 277 custodian and maintenance employees working in buildings with friable asbestos-containing materials and 87 unexposed subjects were studied for radiological abnormalities by use of the International Labour Office (ILO) classification of radiographs of pneumoconiosis, in relation to parameters of asbestos exposure.

Results: The cumulative asbestos exposure index was generally low (fewer than 5 fibres/ml x years in 82.3% of exposed workers). On multivariate analysis, pleural thickening was significantly related to latency since onset of exposure to asbestos in exposed workers, after adjustment for age, body mass index and tobacco smoking.

Conclusions: Asbestos exposure of custodian and maintenance employees in buildings with friable asbestos-containing materials might be associated with an excess of pleural thickening on chest X-rays.

Copyright 2004 Springer-Verlag

In plain English

This multicentre cross-sectional study examined chest X-rays of custodian and maintenance workers in buildings with friable asbestos-containing materials. After exclusions, 277 exposed workers from nine centres in the Paris area, Caen and Lyon were compared with 87 public hospital workers with no known occupational asbestos exposure. Exposure was estimated for each task from a database (Evalutil) rather than measured. Estimated cumulative exposure was under 5 fibres/ml-years in 82.3% of exposed workers. Pleural thickening was seen in 40 exposed workers (14.4%) and 11 controls (12.6%), a difference that was not statistically significant. Among exposed workers, after adjusting for age, body mass index and smoking, pleural thickening was associated with time since first exposure. The odds ratio was 6.14 (95% confidence interval 1.76 to 21.49) for more than 22 years compared with 15 years or less. It was not significantly related to duration of exposure or to estimated cumulative exposure. Small opacities in the lungs were not associated with any exposure measure. The authors concluded that an asbestos-related cause might be suspected. They noted that the exposure estimates were very approximate, no CT scans were available, and non-participants could not be compared with participants.

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: multicentre cross-sectional study
• Who was studied: 277 maintenance and custodian employees working in buildings with friable asbestos-containing materials, recruited from nine centres in the Paris area, Caen and Lyon (336 took part, about 80% of those eligible; 48 were excluded for previous asbestos exposure in other activities and 11 for poor-quality X-rays), compared with 87 public hospital workers with no known occupational asbestos exposure (8 controls excluded for poor X-rays). Mean age was 44.1 years in exposed workers and 47.1 years in controls. 98.2% of exposed workers were male. Study dates are not given.
• Exposure: Work near or on friable asbestos-containing materials, including asbestos flock and asbestos-insulated pipes and boilers. Tasks included equipment repair near flock, drilling, and dry sweeping. Fibre types were not named. Exposure intensity per task was estimated from the French Evalutil database, not measured, and combined with frequency and duration into a cumulative exposure index in 'fibres/ml-years'. The mean was 4 (range 0.0004 to 72.9).
• Main results:
  • Estimated cumulative exposure was under 5 'fibres/ml-years' in 82.3% of exposed workers.
  • Any pleural thickening was found in 40 of 277 exposed workers (14.4%) and 11 of 87 controls (12.6%), P = 0.67. Small opacities of profusion 1/0 or more also did not differ significantly between groups (P = 0.26).
  • Among exposed workers, pleural thickening was associated with latency since onset of exposure in logistic regression adjusted for age, BMI and smoking. The adjusted odds ratio was 6.14 (95% CI 1.76 to 21.49) for latency over 22 years versus 15 years or less, and 3.04 (95% CI 0.96 to 9.64) for 16 to 22 years.
  • Among exposed workers, latency and BMI were the factors significantly associated with pleural thickening in the regression analysis.
  • In the exposed group, duration of exposure was not significantly related to pleural or parenchymal abnormalities in the logistic regression analysis.
  • In the exposed group, small opacities were not associated with any asbestos exposure parameter in the regression analysis.
• The authors' conclusion: The authors concluded that, after accounting for confounding factors, latency since onset of exposure was associated with pleural thickening on chest X-ray but not with small opacities, so that an asbestos-related cause might be suspected.
• Limitations the authors state:
  • There was no information on the age, gender or smoking of non-participants, so they could not be compared with participants, and selection effects might be expected.
  • No airborne measurements were available. Cumulative exposure values were estimates and only very approximate, and workers might have forgotten some interventions.
  • No CT scans were available. The study relied on routine standard chest X-rays.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Friable, Pneumoconiosis, Multivariate Analysis, Pleural Thickening, Latency, Chest X-Ray.

Related studies

• Radiological abnormalities and asbestos exposure among custodians of the New York City Board of Education — S.M. Levin, I.J. Selikoff (1991)
• Respiratory morbidity in workers exposed to asbestos in the primary manufacture of building materials — T.G. Robins, M.A. Green (1988)
• Worker exposure to asbestos during removal of sprayed material and renovation activity in buildings containing sprayed material — N.W. Paik, R.J. Walcott, et al. (1983)
• Comparison of digital with film radiographs for the classification of pneumoconiotic pleural abnormalities — T.C. Larson, D.B. Holiday, et al. (2012)
• Radiological changes in asbestos cement workers — K. Jakobsson, U. Strömberg, et al. (1995)
• Do asbestos-related pleural plaques on HRCT scans cause restrictive impairment in the absence of pulmonary fibrosis? — B. Clin, C. Paris, et al. (2011)

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