Occupation and risk of cancer of the renal pelvis in Nordic countries

Our plain-English summary of Occupation and risk of cancer of the renal pelvis in Nordic countries, by I.M. Michalek, J.I. Martinsen, E. Weiderpass, et al (BJU International, 2019).

The study

• Authors: I.M. Michalek, J.I. Martinsen, E. Weiderpass, K. Kjaerheim, E. Lynge, P. Sparen, L. Tryggvadottir, E. Pukkala
• Journal: BJU International
• Published: 2019;123(2):233-238
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: To evaluate occupational variation in the incidence of the malignant neoplasm of the renal pelvis in the population of the Nordic countries: Denmark, Iceland, Finland, Norway and Sweden.

Materials And Methods: The study cohort comprised 14.9 million individuals. Data on occupational history were obtained from national censuses. Standardized incidence ratios (SIRs) were calculated for each occupation.

Results: The highest SIRs were found in seamen (1.51, 95% confidence interval [CI] 1.23-1.82), printers (1.39, 95% CI 1.11-1.71), welders (1.37, 95% CI 1.03-1.78), and public safety workers (1.35, 95% CI 1.12-1.62). The lowest SIRs were observed in forestry workers (0.47, 95% CI 0.35-0.62), gardeners (0.72, 95% CI 0.62-0.83) and woodworkers (0.81, 95% CI 0.72-0.91).

Conclusions: The study suggests that there is an association between profession and risk of malignancy of the renal pelvis. The possible associations between exposure to asbestos, heavy metals and welding fumes, and risk of developing the disease should be studied further.

© 2018 The Authors BJU International © 2018 BJU International Published by John Wiley & Sons Ltd.

In plain English

This part of the Nordic Occupational Cancer Study (NOCCA) followed 14.9 million people in Denmark, Finland, Iceland, Norway and Sweden who were aged 30 to 64 at a census between 1960 and 1990. It asked whether renal pelvis cancer was more or less common in particular occupations. Job titles came from the censuses; asbestos and other workplace exposures were not measured. Follow-up ran to 2003 to 2005, and 11 237 cases were found. Compared with national rates, the highest statistically significant standardized incidence ratios were in seamen (1.51, 95% CI 1.23 to 1.82), printers (1.39, 1.11 to 1.71), welders (1.37, 1.03 to 1.78) and public safety workers (1.35, 1.12 to 1.62). Ratios significantly below 1 were seen in forestry workers (0.47, 0.35 to 0.62), farmers (0.61, 0.56 to 0.66), gardeners (0.72, 0.62 to 0.83) and woodworkers (0.81, 0.72 to 0.91). In their discussion, the authors suggested the seamen's excess might be linked to asbestos from shipboard insulation. They noted that IARC has not recognized asbestos as a carcinogen for renal pelvis cancer. Smoking was not taken into account. The authors concluded that occupation appeared to be associated with risk, and that links with asbestos, heavy metals and welding fumes should be studied further.

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: Population-based cohort study (part of the Nordic Occupational Cancer Study, NOCCA) using census occupation data linked to cancer registries; standardized incidence ratios calculated per occupation
• Who was studied: 14.9 million people aged 30 to 64 at any census from 1960 to 1990 in Denmark, Iceland, Finland, Norway and Sweden. They contributed 385 million person-years, with follow-up to 2003 to 2005 depending on country. 11 237 renal pelvis cancer cases were identified (4 505 women, 6 732 men).
• Exposure: Occupation as recorded in the first census at entry, coded into 53 occupational groups plus economically inactive persons. No fiber types or exposure measurements were studied; asbestos appears only in the authors' discussion as a possible explanation.
• Main results:
  • Across 11 237 renal pelvis cancer cases (4 505 in women, 6 732 in men), the highest statistically significant SIRs, both sexes combined, were: seamen 1.51 (95% CI 1.23 to 1.82); printers 1.39 (1.11 to 1.71); welders 1.37 (1.03 to 1.78); public safety workers 1.35 (1.12 to 1.62). Some non-significant estimates were higher, for example chimney sweeps 1.73 (0.70 to 3.57).
  • Other significantly raised SIRs: packers 1.23 (1.07 to 1.41), textile workers 1.22 (1.06 to 1.39), painters 1.22 (1.00 to 1.46), transport workers 1.20 (1.01 to 1.42), clerical workers 1.18 (1.09 to 1.27), electrical workers 1.18 (1.02 to 1.36), and food workers 1.16 (1.01 to 1.34).
  • The text names the lowest statistically significant SIRs as forestry workers 0.47 (0.35 to 0.62), gardeners 0.72 (0.62 to 0.83) and woodworkers 0.81 (0.72 to 0.91).
  • Table 1 also shows farmers, with 571 cases, at an SIR of 0.61 (95% CI 0.56 to 0.66). This is lower than gardeners and woodworkers, but the text does not mention it.
  • Over the follow-up period, SIRs rose among public safety workers and fell among food workers and packers.
  • No significant differences in SIRs were seen between countries.
  • Authors' interpretation in the discussion (not measured in this study): the seamen's raised risk may be associated with asbestos fibres released from pipes, gaskets and insulation. The authors noted that IARC has not recognized asbestos as a carcinogen for renal pelvis cancer.
• The authors' conclusion: The authors concluded that the results suggest an association between occupation and risk of renal pelvis cancer. They called for studies that take smoking into account and for further research on possible associations with asbestos, heavy metals and welding fumes.
• Limitations the authors state:
  • Tobacco smoking was not considered as a potential confounding factor.
  • Danish welders could not be analysed separately; they were included with mechanic workers.

Topics

Medical terms in this study, explained in our Lexicon: Neoplasm, Occupational History, Standardized Incidence Ratio (SIR), confidence interval.

Related studies

• Heavy metals, welding fumes, and other occupational exposures, and the risk of kidney cancer: A population-based nested case-control study in three Nordic countries — I.M. Michalek, J.I. Martinsen, et al. (2019)
• Cancer incidence among firefighters: 45 years of follow-up in five Nordic countries — E. Pukkala, J.I. Martinsen, et al. (2014)
• Cancer incidence among seafarers and fishermen in the Nordic countries — K. Ugelvig Petersen, E. Pukkala, et al. (2020)
• International renal-cell cancer study. IV. Occupation — J.S. Mandel, J.K. McLaughlin, et al. (1995)
• Occupational exposure to asbestos and risk of cholangiocarcinoma: a population-based case-control study in four Nordic countries — A. Farioli, K. Straif, et al. (2018)
• Occupational exposures and male breast cancer: A nested case-control study in the Nordic countries — M. Talibov, J. Hansen, et al. (2019)

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