Pleural mesotheliomas and asbestos exposure in the pulp and paper industries: a new risk group identified by linkage of official registers

Our plain-English summary of Pleural mesotheliomas and asbestos exposure in the pulp and paper industries: a new risk group identified by linkage of official registers, by B. Järvholm, H. Malker, B. Malker, et al (American Journal of Industrial Medicine, 1988).

The study

• Authors: B. Järvholm, H. Malker, B. Malker, J. Ericsson, G. Sällsten
• Journal: American Journal of Industrial Medicine
• Published: 1988;13(5):561-7
• Cited by: 28 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. 000234).

Abstract

Analysis of data obtained by linking the 1960 Swedish Census and the Swedish Cancer Registry has demonstrated an increased risk of pleural mesothelioma among pulp and paper workers. The present study was undertaken with the aim of revealing possible environmental risk factors. The work histories of the 25 cases identified earlier were reviewed. "Certain" or "probable" exposure to asbestos was found among 70% of these workers. The study illustrates how linkage of official registers can be used to identify new risk environments and encourage the establishment of preventive measures.

In plain English

This Swedish study looked into an increased risk of pleural mesothelioma among pulp and paper workers. An earlier analysis had found this risk by linking national registers: the 1960 Census and the Cancer Registry, for 1961 to 1979. The authors reviewed the medical records and work histories of the 25 cases, 23 men and 2 women. On review of the pathology, no diagnosis was clearly ruled out. The authors judged at least 18 to be true malignant mesotheliomas and another 4 probable. Eighteen of the 25 had 'certain' or 'probable' asbestos exposure. For 17 of the 24 who worked in pulp or paper mills, that exposure came from their mill work, some of it insulation work or removing insulation. Seventeen had worked at least a year in maintenance. Only six had been exposed to paper dust, and four of those six had also been exposed to asbestos. The type of asbestos was not known. The authors concluded that asbestos exposure was the cause of the increased incidence and that a role for paper dust was unlikely. They noted that their figures probably underestimated true exposure.

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: Case series: review of the medical records, diagnostic material and work histories of mesothelioma cases first identified by linking the 1960 Swedish Census with the Swedish Cancer Registry
• Who was studied: 25 people (23 men and 2 women) in Sweden with pleural mesothelioma diagnosed 1961 to 1979. In the 1960 census all were classified in the paper and allied products industry group. 24 had worked in pulp or paper mills and 1 in the fiberboard industry.
• Exposure: Asbestos exposure during work in pulp and paper mills, for example insulation work or removal of insulation. It was classified as 'certain', 'probable' or 'unknown'. Paper dust exposure was also assessed. The type of asbestos was not known; the authors wrote that both chrysotile and amphiboles were probably used in this industry.
• Main results:
  • 18 of the 25 cases had certain or probable exposure to asbestos. The article prints this as 71%, although 18 of 25 is 72%.
  • 17 of the 24 pulp/paper workers had probable or certain asbestos exposure from their pulp or paper mill work.
  • Some cases were exposed through insulation work or removal of insulation.
  • 17 individuals had worked at least 1 year in maintenance departments, and 2 had worked at least 1 year as stokers.
  • 6 individuals had been exposed to paper dust, and 4 of these 6 had also been exposed to asbestos. The authors estimated that about one-third of the total workforce in the industry is exposed to paper dust.
  • The time from first asbestos exposure to diagnosis could be determined for 9 of the 11 cases with certain exposure. It was 15 years in 1 case, 19 years in 1 case, and at least 20 years in 7 cases.
  • On review of the diagnostic material, no case was clearly excluded as malignant pleural mesothelioma.
  • The authors judged at least 18 of the 25 cases to be true malignant mesotheliomas and another 4 to be probable cases. The 3 remaining cases could not be excluded as mesotheliomas.
• The authors' conclusion: The authors concluded that asbestos exposure is the cause of the increased incidence of pleural mesothelioma in Swedish pulp and paper workers. They also judged their secondary hypothesis, that paper dust caused pleural mesothelioma, unlikely.
• Limitations the authors state:
  • Cases classified as having 'unknown' exposure might in fact have been exposed to asbestos to a considerable extent.
  • Company health departments could usually provide employment history only for their own company.
  • The authors described their exposure histories as rough and said the share of exposed cases is probably an underestimate.
  • There was no information on the type of asbestos used.
  • In register studies of this kind, the job classification usually refers only to one point in time.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Asbestos Exposure, Cancer Registry.

Related studies

• Health effects of working in pulp and paper mills: malignant diseases — K. Torén, B. Persson, et al. (1996)
• Cohort mortality study of pulp and paper mill workers in British Columbia, Canada — P.R. Band, N.D. Le, et al. (1997)
• Exposure to asbestos and lung and pleural cancer mortality among pulp and paper industry workers — R. Carel, P. Boffetta, et al. (2002)
• Cancer incidence among Swedish pulp and paper mill workers: a cohort study of sulphate and sulphite mills — E. Andersson, H. Westberg, et al. (2013)
• Asbestos fibers in ovarian tissue from Norwegian pulp and paper workers — H. Langseth, B.V. Johansen, et al. (2007)
• Occupations and industries in France at high risk for pleural mesothelioma: A population-based case-control study (1998-2002) — P. Rolland, C. Gramond, et al. (2010)

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