Exposure to stainless steel welding fumes and lung cancer: a meta-analysis

Our plain-English summary of Exposure to stainless steel welding fumes and lung cancer: a meta-analysis, by B. Sjögren, K.S. Hansen, H. Kjuus, et al (Occupational and Environmental Medicine, 1994).

The study

• Authors: B. Sjögren, K.S. Hansen, H. Kjuus, P.G. Persson
• Journal: Occupational and Environmental Medicine
• Published: 1994;51(5):335-6
• Type of article: Meta-analysis
• Cited by: 61 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Stainless steel welding is associated with exposure to metals including hexavalent chromium and nickel. This study is a meta-analysis of five studies of stainless steel welders and the occurrence of lung cancer. Asbestos exposure and smoking habits have been taken into account. The calculated pooled relative risk estimate was 1.94 with a 95% confidence interval of 1.28-2.93. This result suggests a causal relation between exposure to stainless steel welding and lung cancer.

In plain English

This article was a meta-analysis, a method that pools results from earlier studies. It looked at lung cancer in welders exposed to stainless steel welding fumes, which contain metals including chromium and nickel. The authors searched two literature databases covering 1984 to 1993. They stated that only studies taking smoking and asbestos exposure into account were included. Five studies qualified, from Canada, Denmark, France, Norway and Sweden. The Swedish study itself had not taken smoking into account, so the authors adjusted its figure by assuming smoking was 10% more common among the welders. They also recalculated the French figure using assumptions about smoking. The individual estimates ranged from 0.97 (France) to 3.3 (Canada). Excluded studies included a German study in which three mesothelioma cases indicated asbestos exposure, and a Los Angeles study that did not adjust for asbestos. Combining the five studies, the pooled relative risk of lung cancer for stainless steel welders was 1.94 (95% confidence interval 1.28 to 2.93). The authors concluded that this clearly indicates a relation between stainless steel welding fumes and lung cancer once smoking and asbestos exposure are taken into account.

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: Meta-analysis of five published studies (case-referent and cohort studies), pooled using inverse-variance weights; the authors' stated rule was to include only studies taking smoking and asbestos exposure into account
• Who was studied: Five studies of welders exposed to stainless steel welding fumes, from Canada, Denmark, France, Norway and Sweden, identified in MEDLINE and NIOSHTIC searches covering 1984 to 1993
• Exposure: Stainless steel welding fumes, which contain metals including chromium (including hexavalent chromium) and nickel; smoking and asbestos exposure were treated as confounders
• Main results:
  • Pooled relative risk of lung cancer across the five studies: 1.94 (95% CI 1.28 to 2.93)
  • Canadian case-referent study (Montreal men aged 35 to 70): odds ratio 3.3 (95% CI 1.2 to 9.2) for lung cancer in welders exposed to nickel
  • Danish nested case-referent study: odds ratio 1.57 (95% CI 0.85 to 2.89) for ever stainless steel welding, after adjusting for smoking and asbestos exposure
  • French subcohort of predominantly stainless steel welders: 2 lung cancers vs 1.95 expected; the authors recalculated the standardised mortality ratio for smoking as 0.97
  • Norwegian case-referent study: with both asbestos exposure and smoking in the model, odds ratio 2.56 (95% CI 0.85 to 7.54)
  • Swedish cohort of 234 welders: smoking was not taken into account in the original study; 5 lung cancers vs 2.01 expected (SMR 2.49). After the authors' smoking adjustment, the SMR was 2.04 (95% CI 0.66 to 4.76)
  • Study selection: a German study of 1221 welders was excluded; three mesothelioma cases among its welders indicated asbestos exposure
  • Study selection: a Los Angeles county case-referent study was excluded because it did not adjust for asbestos exposure
• The authors' conclusion: The authors concluded that the result clearly indicates a relation between stainless steel welding fumes and lung cancer, once smoking habits and asbestos exposure (which they called the two most important confounders) are taken into account
• Limitations the authors state:
  • The Swedish cohort study did not take smoking into account; the authors adjusted it by assuming smoking was 10% more prevalent among the welders
  • The French figure relied on the authors' assumption that the stainless steel subcohort smoked like the main welder cohort

Topics

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

Medical terms in this study, explained in our Lexicon: Lung Cancer, Meta-Analysis, Asbestos Exposure, Habit, Relative Risk, confidence interval.

Related studies

• Cancer incidence among mild steel and stainless steel welders and other metal workers — K.S. Hansen, J.M. Lauritsen, et al. (1996)
• A historical prospective study of European stainless steel, mild steel, and shipyard welders — L. Simonato, A.C. Fletcher, et al. (1991)
• Welding fumes and lung cancer: a meta-analysis of case-control and cohort studies — M.K. Honaryar, R.M. Lunn, et al. (2019)
• 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)
• Response of bovine alveolar macrophages in vitro to welding fume particles — L.R. White, A.B. Marthinsen, et al. (1983)
• Risk of lung cancer in workers producing stainless steel and metallic alloys — J.J. Moulin, T. Clavel, et al. (2000)

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