Incidence of cancer among welders and other workers in a Norwegian shipyard

Our plain-English summary of Incidence of cancer among welders and other workers in a Norwegian shipyard, by A. Melkild, S. Langård, A. Andersen, et al (Scandinavian Journal of Work, Environment & Health, 1989).

The study

• Authors: A. Melkild, S. Langård, A. Andersen, J.N. Tønnessen
• Journal: Scandinavian Journal of Work, Environment & Health
• Published: 1989;15(6):387-94
• Cited by: 37 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The incidence of cancer among 4778 male shipyard workers, including 783 mild steel welders, was investigated in a historical cohort study. The workers had been employed for at least three months between 1 January 1946 and 31 March 1977. The incidence of cancer was observed from 1 January 1953 through 1986. The loss during follow-up was only 0.9%. There were 53 observed cases of lung cancer in the whole cohort versus 31.3 expected on the basis of the national rates for men. There was an increased incidence of lung cancer among the welders, with seven observed cases versus 3.2 expected. Twenty-two cases of bladder cancer were observed versus 15.2 expected. Two malignant mesotheliomas had occurred (0.7 expected). Smoking was likely to be a confounder in the present study. Due to concomitant exposure to asbestos, the results are inconclusive concerning the possible relationship between exposure to welding fumes and lung cancer.

In plain English

This historical cohort study followed 4778 men who had worked for at least three months at a shipyard on the southwestern coast of Norway, including 783 welders who had mainly welded mild steel. Cancers occurring from 1953 through 1986 were compared with the numbers expected from national rates for Norwegian men. Asbestos, almost exclusively chrysotile, was used at the yard until the early 1970s. In the whole cohort there were 53 lung cancers against 31.3 expected, 22 bladder cancers against 15.2 expected, and 252 cancers overall against 244.1 expected. Two malignant mesotheliomas occurred against 0.7 expected. Among the welders, 7 lung cancers occurred against 3.2 expected, but the welders' lung cancer ratio was no higher than that of the other job groups. The lung cancer excess was largest among men employed for less than one year (21 observed, 7.5 expected). No information on the workers' smoking was available. The authors concluded that smoking was likely a confounder and that, because of concurrent asbestos exposure, the results were inconclusive about welding fumes and lung cancer.

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: Historical cohort study of cancer incidence, with expected numbers based on national rates for men
• Who was studied: 4778 male workers at a shipyard on the southwestern coast of Norway, including 783 mild steel welders. All had been employed for at least three months. Cancer incidence was followed from 1 January 1953 through 1986.
• Exposure: Welding fumes, mainly from mild steel welding, with virtually no stainless steel welding up to 1973 to 1974. Asbestos was used at the yard until the early 1970s, and the asbestos used was almost exclusively chrysotile. Zinc chromate primers were also used.
• Main results:
  • Whole cohort: 53 observed cases of lung cancer versus 31.3 expected on the basis of national rates for men
  • Welders: 7 observed cases of lung cancer versus 3.2 expected
  • The overall standardized incidence ratio for lung cancer among the welders did not exceed that of the other occupational categories
  • Welders employed for 1 to 5 years: 5 observed lung cancers versus 0.9 expected
  • Whole cohort: 22 cases of bladder cancer versus 15.2 expected
  • Whole cohort: 2 cases of malignant mesothelioma versus 0.7 expected. One was in a turner employed in 1946 for less than one year, and one in a shipwright employed from 1950 to 1965.
  • Whole cohort: 252 cases of cancer at all sites versus 244.1 expected
  • Workers employed for less than one year: 21 observed lung cancers versus 7.5 expected (SIR 280)
• The authors' conclusion: The authors concluded that smoking was likely a confounder and that, because of concomitant exposure to asbestos, the results were inconclusive concerning a possible relationship between exposure to welding fumes and lung cancer.
• Limitations the authors state:
  • No information was available on the smoking habits of the cohort.
  • Measurements of asbestos dust concentrations for the period of interest were not available.
  • The observation period may have been too short to reveal a possible excess of mesothelioma, and the small numbers preclude further interpretation.
  • The extent to which previous welding experience at other shipyards or in other industries influenced the results is not known.

Topics

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

Medical terms in this study, explained in our Lexicon: Cohort Study, Lung Cancer, Mesothelioma.

Related studies

• Incidence of lung cancer among shipyard welders investigated for siderosis — T.E. Danielsen, S. Lang rd, et al. (1998)
• Incidence of cancer among Norwegian boiler welders — T.E. Danielsen, S. Langård, et al. (1996)
• Mortality of welders and other craftsmen at a shipyard in NE England — M.L. Newhouse, D. Oakes, et al. (1985)
• Cancer incidence among mild steel and stainless steel welders and other metal workers — K.S. Hansen, J.M. Lauritsen, et al. (1996)
• Incidence of cancer among welders, platers, machinists, and pipe fitters in shipyards and machine shops — S. Tola, P.L. Kalliomäki, et al. (1988)
• Mortality and incidence of cancer among oil exposed workers in a Norwegian cable manufacturing company. Part I. Exposure conditions 1920-79 — A. Rønneberg, K. Skyberg (1988)

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