Health effects of working in pulp and paper mills: malignant diseases

Our plain-English summary of Health effects of working in pulp and paper mills: malignant diseases, by K. Torén, B. Persson, G. Wingren (American Journal of Industrial Medicine, 1996).

The study

• Authors: K. Torén, B. Persson, G. Wingren
• Journal: American Journal of Industrial Medicine
• Published: 1996;29(2):123-30
• Type of article: Review
• Cited by: 36 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This paper reviews the available literature regarding the work environment in pulp and paper mills and the risk for malignant diseases. An increased risk for lung cancer among pulp and paper mill workers has been reported. Most studies are inconclusive with regard to considerations of etiologic agents. However, maintenance workers seem to be at an increased risk for lung cancer, as well as for malignant mesothelioma, indicating that this occupational group was (is) exposed to asbestos. Workers exposed to chlorine compounds also seem to run an increased risk for lung cancer. An increased risk for malignant lymphomas among pulp mill workers is a constant finding. The increased risk is observed both among sulfite and sulfate workers, indicating a common exposure. Such an exposure could be wood dust, terpenes, or preservatives present in the wood. An increased risk for leukemias has been found in many studies carried out on pulp and paper workers, but the studies do not permit any conclusions about etiologic factors. In some studies an increased risk for stomach cancer has been found. However, the socioeconomic status of the workers is strongly related to stomach cancer, and factors, such as dietary habits, have not been taken into account in any of the reviewed studies. Hence, no further conclusions can be drawn regarding etiologic agents.

In plain English

This article was a review of published cohort, case-referent and proportionate mortality studies, up to January 1, 1995, on cancer among pulp and paper mill workers. Among the reviewed studies, Finnish maintenance workers had a lung cancer SIR of 127 (95% CI 92-170). Swedish maintenance workers in another study had a lung cancer odds ratio of 2.1 (95% CI 1.2-3.7), and all three mesothelioma cases in that study had been maintenance workers. A Swedish register linkage found an increased risk of pleural mesothelioma among pulp and paper workers (SIR 290, p less than 0.05). Of 25 cases analyzed further, 18 had certain or probable asbestos exposure. Increased lymphoma risk estimates appeared in 12 of 13 populations, and increased leukemia estimates in 9 of 14. The authors noted that many studies lacked precise exposure assessment. They concluded that lung cancer, malignant mesothelioma and malignant lymphomas should be regarded as connected to occupational exposures in these mills, and that asbestos exposure is an important risk factor for respiratory system cancers.

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: Literature review of cohort, case-referent and proportionate mortality studies; ecological studies excluded
• Who was studied: Published epidemiological studies of pulp and paper mill workers (including studies from the United States, Canada, Finland and Sweden), literature up to January 1, 1995
• Exposure: Work in pulp and paper mills (sulfite, sulfate, paper mill, board mill, maintenance and other jobs). The authors discuss asbestos used in brake discs, insulation and as a filler in certain papers (no fiber type named), as well as chlorine compounds and wood dust.
• Main results:
  • In a reviewed Finnish cohort (Jappinen et al., 1987), maintenance workers had a lung cancer SIR of 127 (95% CI 92-170).
  • In a reviewed Swedish register linkage (Malker et al., 1985), pulp and paper workers had an increased risk of pleural mesothelioma (SIR 290, p less than 0.05).
  • In a follow-up of those mesothelioma cases (Järvholm et al., 1988), 25 of the 27 cases were analyzed further, and 18 of them (71%) had certain or probable asbestos exposure. The majority (17) of the asbestos-exposed workers had worked at least 1 year in maintenance.
  • In a reviewed Swedish case-referent study (Torén et al., 1991), maintenance workers had an increased lung cancer risk (OR 2.1, 95% CI 1.2-3.7), but process workers did not.
  • In the same study (Torén et al., 1991), all three mesothelioma cases found had been maintenance workers at the mills.
  • In a reviewed Finnish study (Jappinen and Pukkala, 1991), workers exposed to chlorine compounds had an increased lung cancer risk (SIR 300, 95% CI 110-660 as given in the text).
  • Across the reviewed studies, malignant lymphomas were found in 13 populations, and 12 of them had an increased risk estimate (above 120).
  • Leukemias were found in 14 populations, and nine of them had an increased risk estimate (above 120). The authors judged these findings less consistent than those for lymphomas.
  • For stomach cancer, studies that separated the different processes pointed, to some extent, to an increased risk among sulfite mill workers.
• The authors' conclusion: The authors concluded that lung cancer, malignant mesothelioma and malignant lymphomas should be regarded as connected to occupational exposures in pulp and paper mills, and that asbestos exposure is an important risk factor for respiratory system cancers.
• Limitations the authors state:
  • Many of the reviewed studies lacked precise exposure assessment.
  • Smoking is a confounder that must be considered in lung cancer studies.
  • None of the reviewed stomach cancer studies took into account socioeconomic factors such as dietary habits.
  • The lymphoma studies were inconclusive about exposure because occupations or exposure histories were not presented.

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Malignant Mesothelioma, Stomach Cancer, Habit.

Related studies

• Cohort mortality study of pulp and paper mill workers in British Columbia, Canada — P.R. Band, N.D. Le, et al. (1997)
• Cancer incidence among Swedish pulp and paper mill workers: a cohort study of sulphate and sulphite mills — E. Andersson, H. Westberg, et al. (2013)
• Exposure to asbestos and lung and pleural cancer mortality among pulp and paper industry workers — R. Carel, P. Boffetta, et al. (2002)
• Pleural mesotheliomas and asbestos exposure in the pulp and paper industries: a new risk group identified by linkage of official registers — B. Järvholm, H. Malker, et al. (1988)
• Asbestos fibers in ovarian tissue from Norwegian pulp and paper workers — H. Langseth, B.V. Johansen, et al. (2007)
• A case-referent study of cancer mortality among sulfate mill workers in Sweden — E. Andersson, S. Hagberg, et al. (2001)

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