Biliary tract cancer and occupation in Sweden

Our plain-English summary of Biliary tract cancer and occupation in Sweden, by H.S. Malker, J.K. McLaughlin, B.K. Malker, et al (British Journal of Industrial Medicine, 1986).

The study

• Authors: H.S. Malker, J.K. McLaughlin, B.K. Malker, B.J. Stone, J.A. Weiner, J.L. Ericsson, W.J. Blot
• Journal: British Journal of Industrial Medicine
• Published: 1986;43(4):257-62
• Cited by: 35 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001165).

Abstract

Using the Cancer-Environment Registry, which links the incidence of cancer (1961-79) and the 1960 census data on industry and occupation for all employed individuals in Sweden, the occurrence of biliary tract cancer (ICD 7th rev 155.1-.9) was systematically assessed according to occupational and industrial classifications. Data are presented separately for cancer of the gall bladder (ICD 155.1) and other cancers of the biliary tract (ICD 155.2-.9) including cancers of the extrahepatic bile ducts, ampulla of Vater, and unspecified bile passages. Statistically significant increased risks for cancer of the gall bladder were observed for men employed in petroleum refining, papermills, chemical processing, shoemaking, and repairing, and for both men and women employed in textile work. A significant increase in the incidence of other cancers of the biliary tract (mostly cancers of the bile duct) was found for such asbestos related employment as shipbuilding and in the wholesale construction materials industry and among insulation workers. These findings should be considered only as clues to aetiological factors, although several are consistent with earlier observations from other countries.

In plain English

This Swedish record linkage study joined the 1960 national census, which recorded each employed person's industry and occupation, with cancer registry data for 1961 to 1979. The authors compared observed and expected cancer counts by job and industry, separately for gall bladder cancer and for other biliary tract cancers, mostly of the bile ducts. Men had 1304 gall bladder and 764 other biliary tract cancers. Women had 947 and 346. Asbestos was not measured. Among men, insulation workers in the other construction industry had a standardised incidence ratio of 10.6 for other biliary tract cancers, based on 2 cases. Men in the wholesale building materials industry had a ratio of 2.3 (12 cases). Among women in shipbuilding and repair the ratio was 7.3 (3 cases). The authors wrote that these may be linked to asbestos exposure. Men in petroleum refining had a ratio of 3.8 for gall bladder cancer (6 cases). The authors cautioned that with so many comparisons some findings may be chance, and that the registry lacked data on employment duration and gall stones. They offered the results as hypotheses, not causes.

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: Record linkage study comparing observed with expected cancer cases (standardised incidence ratios) by industry and occupation; described by the authors as hypothesis generating
• Who was studied: All individuals employed in Sweden at the 1960 census, followed for cancer incidence 1961-79. Men had 1304 gall bladder cancers and 764 other biliary tract cancers. Women had 947 gall bladder cancers and 346 other biliary tract cancers.
• Exposure: Industry and occupation as recorded in the 1960 census. Asbestos exposure was not measured. The authors suggested that some job groups (insulation work, wholesale building materials, shipbuilding) may involve asbestos exposure.
• Main results:
  • Men who were insulation workers in the other construction industry had a standardised incidence ratio of 10.6 for other biliary tract cancers, based on 2 cases.
  • Men in the wholesale building materials industry had a statistically significant standardised incidence ratio of 2.3 for other biliary tract cancers, based on 12 cases.
  • Women in shipbuilding and repair had a statistically significant standardised incidence ratio of 7.3 for other biliary tract cancer, based on 3 cases.
  • Men in petroleum refining had a statistically significant standardised incidence ratio of 3.8 for gall bladder cancer, based on 6 cases.
  • Among general manufacturing and craft groups for men, the only significantly raised ratio for other biliary tract cancers was in the other construction industry.
  • Women in papermills had a raised standardised incidence ratio of 1.9 for gall bladder cancer, based on 9 cases.
• The authors' conclusion: The authors concluded that the registry's limitations prevent drawing conclusions about cause. They offered the significant associations as hypotheses for future research. They noted that the excesses in insulation work, wholesale building materials and women's shipbuilding employment may be linked to asbestos exposure.
• Limitations the authors state:
  • The registry had no information on duration of employment or on other risk factors such as gall stones.
  • Many comparisons were made, so some significant findings may be due to chance.
  • The high ratios for specific job categories were based on small numbers of cases.
  • Census job classifications agreed less well with reinterview data at the detailed (three digit) level.
  • Expected numbers were not based on person-years, because the study lacked information on loss to follow up.

Topics

Medical terms in this study, explained in our Lexicon: Insulator.

Related studies

• Occupation and male lung cancer: a case-control study in northern Sweden — L.A. Damber, L.G. Larsson (1987)
• Occupation and mesothelioma in Sweden: updated incidence in men and women in the 27 years after the asbestos ban — N. Plato, J.I. Martinsen, et al. (2016)
• Blue-collar work is a risk factor for developing IgG4-related disease of the biliary tract and pancreas — L.M. Hubers, A.R. Schuurman, et al. (2021)
• Asbestos fibers in the gallbladder of patients affected by benign biliary tract diseases — F. Grosso, L. Randi, et al. (2015)
• Cytokeratin 5/6 immunostaining in hepatobiliary and pancreatic neoplasms — D.M. Vlasoff, D.Y. Baschinsky, et al. (2002)
• Occupational exposure and lung cancer risk: a population-based case-referent study in Sweden — P. Gustavsson, R. Jakobsson, et al. (2000)

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