Incidence of cancer among Norwegian boiler welders

Our plain-English summary of Incidence of cancer among Norwegian boiler welders, by T.E. Danielsen, S. Langård, A. Andersen (Occupational and Environmental Medicine, 1996).

The study

• Authors: T.E. Danielsen, S. Langård, A. Andersen
• Journal: Occupational and Environmental Medicine
• Published: 1996;53(4):231-4
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: The cancer incidence among 2957 boiler welders was investigated. The subjects were registered electrical welders from 1942 to 1981. A subcohort of 606 stainless steel welders was studied separately.

Methods: The investigation was a historical prospective cohort study based on a national registry. The loss of follow up was 4.9%.

Results: There were 625 deaths (659 expected). There were 269 cancer cases (264 expected). An excess of lung cancer was found; 50 cases v 37.5 expected. There were three cases of pleural mesotheliomas v 1.1 expected. The subcohort of stainless steel welders had six cases of lung cancer v 5.8 expected, and one case of pleural mesothelioma v 0.2 expected.

Conclusions: The welders in the study were assumed to represent a qualified work force. These welders had a small excess risk of lung cancer. The excess risk did not seem to be associated with stainless steel welding. Smoking and asbestos exposure were potential confounders.

In plain English

This historical cohort study followed 2957 Norwegian men registered as electric boiler welders between 1942 and 1981, including 606 who had welded stainless steel, for cancer from 1953 to 1992. Cancer counts were compared with numbers expected from rates among Norwegian men. The whole cohort had 269 cancers against 264 expected, and 50 lung cancers against 37.5 expected (standardised incidence ratio 133, 95% confidence interval 99 to 176). There were 3 pleural mesotheliomas against 1.1 expected and 19 kidney cancers against 10.7 expected. Stainless steel welders had 6 lung cancers against 5.8 expected and 1 pleural mesothelioma against 0.2 expected. Asbestos was used until the mid 1970s in most businesses employing these welders, but the authors had no exposure measurements and no information on individual smoking. The authors concluded that the welders seemed to carry a small excess risk of lung cancer that could not be attributed to the subcohort of stainless steel welders, and that asbestos exposure and smoking probably accounted for a major part of it.

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 prospective cohort study based on a national registry of boiler welders, linked to the Cancer Registry of Norway
• Who was studied: 2957 male boiler welders registered for electric welding in the Norwegian National Registry of Boiler Welders from 1942 to 1981, including a subcohort of 606 who had ever welded stainless steel. Cancer cases were counted from 1953 to 1992, giving 68 993 person-years. 153 welders (4.9%) could not be identified.
• Exposure: Electric welding fumes, mostly from mild steel welding, with a subcohort who also welded stainless steel. Asbestos was used until the mid 1970s in most of the businesses employing the welders. No fiber type is named, and asbestos exposure was not measured for individuals.
• Main results:
  • Whole cohort: 625 deaths against 659 expected (standardised mortality ratio 95)
  • Whole cohort: 269 cancers of all sites against 264 expected
  • Whole cohort: 50 lung cancers against 37.5 expected, standardised incidence ratio 133 (95% confidence interval 99 to 176)
  • Whole cohort: 3 pleural mesotheliomas against 1.1 expected, standardised incidence ratio 273 (95% confidence interval 55 to 800)
  • Whole cohort: 19 kidney cancers against 10.7 expected, standardised incidence ratio 178 (95% confidence interval 107 to 278)
  • Whole cohort: 11 leukaemias against 6.2 expected (standardised incidence ratio 177)
  • Stainless steel subcohort: 6 lung cancers against 5.8 expected, standardised incidence ratio 103 (95% confidence interval 38 to 226)
  • Stainless steel subcohort: 1 pleural mesothelioma against 0.2 expected, standardised incidence ratio 500 (95% confidence interval 0 to 2800)
  • Whole cohort, after excluding the first 15 years from estimated first exposure: 46 lung cancers against 36.1 expected and 3 pleural mesotheliomas against 1.0 expected
  • Welders first registered in the 1950s had the highest lung cancer incidence in the whole cohort (standardised incidence ratio 170; 25 observed against 14.7 expected)
• The authors' conclusion: The authors concluded that the welders seemed to carry a small excess risk of lung cancer, that the overall excess could not be attributed to the subcohort of stainless steel welders, and that the specific effect of welding fumes is disputable.
• Limitations the authors state:
  • The authors stated that confounding by asbestos exposure and tobacco smoking probably accounts for a major part of the excess lung cancer risk.
  • There was no information on individual smoking habits.
  • The end date of welding work was unknown, so the cohort could not be grouped by duration of exposure.
  • No workplace environmental monitoring data were available from any of the businesses.
  • The cohort may have been selected for good health (highly skilled, employer-selected welders).

Topics

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

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

Related studies

• Cancer incidence among mild steel and stainless steel welders and other metal workers — K.S. Hansen, J.M. Lauritsen, et al. (1996)
• Incidence of lung cancer among shipyard welders investigated for siderosis — T.E. Danielsen, S. Lang rd, et al. (1998)
• Incidence of cancer among welders and other workers in a Norwegian shipyard — A. Melkild, S. Langård, et al. (1989)
• A historical prospective study of European stainless steel, mild steel, and shipyard welders — L. Simonato, A.C. Fletcher, et al. (1991)
• Incidence of cancer among welders, platers, machinists, and pipe fitters in shipyards and machine shops — S. Tola, P.L. Kalliomäki, et al. (1988)
• Incidence of cancer and mortality among workers exposed to mercury vapour in the Norwegian chloralkali industry — D.G. Ellingsen, A. Andersen, et al. (1993)

Browse more research in Occupational and Environmental Medicine, or return to medical research.