Retention of asbestos bodies in the lungs of welders

Our plain-English summary of Retention of asbestos bodies in the lungs of welders, by J.C. Pairon, L. Martinon, Y. Iwatsubo, et al (American Journal of Industrial Medicine, 1994).

The study

• Authors: J.C. Pairon, L. Martinon, Y. Iwatsubo, F. Vallentin, M.A. Billon-Galland, J. Bignon, P. Brochard
• Journal: American Journal of Industrial Medicine
• Published: 1994;25(6):793-804
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Examination of asbestos bodies (AB) retained in the lungs is a useful way of assessing past occupational exposure to this material. AB retention has been extensively studied in workers directly exposed to asbestos, but less so in those end users, such as welders, who use asbestos-containing products. We therefore retrospectively studied AB retention in 211 welders, for whom biological testing procedures had been requested by a chest physician, between 1988 and 1991. Optical microscopy of AB was performed on samples of sputum (40 subjects), bronchoalveolar lavage fluid (BAL) (147 subjects), and lung tissue obtained after thoracotomy (38 subjects). Information on previous jobs and exposure was obtained using a questionnaire (the mean duration of welding activities was 16.6 years). Eighty-two subjects (38.9%) had elevated lung retention of AB in all the samples studied. Significant AB retention occurred in only 30% of sputum samples, but in 40.1% of BAL samples and 39.5% of lung tissue samples. The duration of welding activities correlated with the density of AB in BAL or lung tissue (r = 0.31, p < 0.01 and r = 0.49, p < 0.05, respectively). On the basis of the questionnaire, only two of the welders with significant AB retention had other occupational exposure to asbestos. Our findings suggest that welding activities may increase lung retention of AB, and consequently might produce higher risks of fibrotic and/or malignant pulmonary diseases. These potential risks need to be brought to the attention of doctors; a longitudinal follow-up may also be warranted in such populations, even after individuals have ceased their welding jobs.

In plain English

This French study reviewed laboratory results for 211 male welders whose chest physicians sent samples for asbestos body counting in 1988 to 1991. Asbestos bodies were counted by optical microscopy in sputum (40 men), bronchoalveolar lavage fluid (147) and lung tissue (38). For 204 men, welding was the only job linked to possible asbestos exposure. Overall, 82 welders (38.9%) had significant retention by the laboratory's cutoffs. Those with high retention were older and had welded longer. Welding duration correlated with asbestos body levels in lavage fluid (r = 0.31) and lung tissue (r = 0.49). Compared with the shortest class (1 to 8 years of welding), men who had welded more than 20 years had an odds ratio of 3.53 (95% limits 1.54 to 8.10) for high retention. The share with high retention did not differ significantly between disease groups or industry groups. The authors concluded that welding may lead to significant lung retention of asbestos bodies, while its role in lung cancer or fibrosis is unclear. They noted the welders were a selected group, almost 80% with diseases possibly linked to asbestos.

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: Retrospective study of laboratory asbestos body counts in samples referred by chest physicians
• Who was studied: 211 male welders in France whose chest physicians sent sputum (40), bronchoalveolar lavage (147) or lung tissue (38) samples from more than 30 French hospitals, 1988 to 1991
• Exposure: Welding work (mean duration 16.6 years). Welding was the only job related to potential asbestos exposure in 204 subjects. No details on welding processes were available, and fiber types were not identified; asbestos bodies were counted by optical microscopy.
• Main results:
  • 82 of the 211 welders (38.9%) had significant lung retention of asbestos bodies.
  • By sample type, significant retention was found in 30% of sputum samples, 40.1% of lavage samples and 39.5% of lung tissue samples.
  • The high-retention group was older and had welded longer than the group without significant retention. There was no difference in time since the end of welding or in smoking habits.
  • Duration of welding correlated with log asbestos body concentration in lavage fluid (r = 0.31, p less than 0.01) and in lung tissue (r = 0.49, p less than 0.05).
  • In a logistic regression that split welding duration into 1-8, 9-19 and more than 20 years, welders with more than 20 years had an odds ratio of 3.53 (95% limits: 1.54-8.10) for high asbestos body retention. Odds ratios were reported only for the two longer classes, so the 1-8 year class was the comparison.
  • Welders with 9 to 19 years of welding had an odds ratio of 0.92 (95% limits: 0.38-2.27), relative to the same 1-8 year class.
  • The proportion with significant retention did not differ between industry groups: 11/19 (57.9%) in the high-probability group, 26/61 (42.6%) in the low-probability group and 45/131 (34.4%) where the industry was unknown.
  • Welders in high-probability industries (shipyards, power stations, district heating) had higher lung tissue concentrations (26,750 asbestos bodies per gram of dry lung tissue) than those in low-probability industries (956 per gram) (p less than 0.05).
  • The share with significant retention did not differ between welders with interstitial pulmonary fibrosis or lung cancer (35.4%) and those with pleural fibrosis or mesothelioma (48.5%).
  • No correlation was found between asbestos body concentration and age, smoking habits, or time since the end of welding.
• The authors' conclusion: The authors concluded that welding may lead to significant lung retention of asbestos bodies, but that the role of this retention in lung cancer and/or pulmonary fibrosis among welders is unclear.
• Limitations the authors state:
  • The study population was selected: almost 80% had lung diseases associated or potentially associated with asbestos exposure.
  • The only occupational history available was what the chest physician collected. There was no information on exposure levels, welding techniques or domestic exposure.
  • These gaps may have biased the study toward welders who had been highly exposed. Exposure outside the workplace could not be excluded.
  • Industrial sector was unknown for over 60% of subjects, which reduced statistical power.
  • Diagnoses came from the referring chest physician and may have been erroneous. For example, mesothelioma and pleural fibrosis may have been confused.
  • Patients could not be classified by severity of fibrosis.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Occupational Exposure, Sputum, Bronchoalveolar Lavage (BAL), Thoracotomy.

Related studies

• Incidence of cancer among welders, platers, machinists, and pipe fitters in shipyards and machine shops — S. Tola, P.L. Kalliomäki, et al. (1988)
• Case-control study of lung cancer in Los Angeles county welders — C.J. Hull, E. Doyle, et al. (1989)
• A historical prospective study of European stainless steel, mild steel, and shipyard welders — L. Simonato, A.C. Fletcher, et al. (1991)
• Cancer incidence among mild steel and stainless steel welders and other metal workers — K.S. Hansen, J.M. Lauritsen, et al. (1996)
• Mortality of welders and other craftsmen at a shipyard in NE England — M.L. Newhouse, D. Oakes, et al. (1985)
• Nickel-related cancer in welders — S. Langård (1994)

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