Lung cancer risk and welding: results from a case-control study in Germany

Our plain-English summary of Lung cancer risk and welding: results from a case-control study in Germany, by K.H. Jöckel, W. Ahrens, H. Pohlabeln, et al (American Journal of Industrial Medicine, 1998).

The study

• Authors: K.H. Jöckel, W. Ahrens, H. Pohlabeln, U. Bolm-Audorff, K.M. Müller
• Journal: American Journal of Industrial Medicine
• Published: 1998;33(4):313-20
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

In a case-control study, 839 male hospital-based cases of primary lung cancer and the same number of population-based controls--matched by sex, age, and region of residence--were personally interviewed for their job and smoking histories. The study allows to quantify occupational asbestos exposure that was thought to be a welding-associated risk: 6% of cases and 2% of controls were classified into the occupational category "welders or burners# (odds ratio [OR] = 2.65). This OR was reduced to 1.93 (95% confidence limit [CL]: 1.03-3.61) after adjustment for smoking and asbestos. In contrast, a history of welding in general for at least a half-year is 28% among cases and 23% among controls, yielding an OR of 1.25 (95% CL: 0.94-1.65) after adjustment for both confounders. The OR of welding for more than 6,000 hr is 1.45 (95% CL = 1.04-2.02), reduced to 1.10 after adjustment for smoking and asbestos. Oxyacetylene welding for more than 6,000 hr lifelong is associated with an OR of 1.86 (95% CL = 1.01-3.43) reduced to 1.46 (n.s.) after adjustment for smoking and asbestos. The risk of oxyacetylene welding seems to be highest for oat cell carcinoma with an adjusted OR for ever-exposure of 1.46 (95% CL = 0.69-3.10). Therefore, the present study supports the hypothesis that some, but not all, of the excess risk of welders observed in the literature may be due to a history of cigarette smoking and occupational asbestos exposure. The elevated risk for the subgroup of employees in the aircraft industry reported for the midterm evaluation of the study still prevails, though no longer statistically significant. However, employees in this industry who ever welded show an OR of 2.29 (95% CL = 1.19-4.42) after adjustment for smoking and asbestos.

In plain English

This German case-control study compared 839 men with lung cancer from hospitals in Bremen and Frankfurt (1988 to 1993) with 839 population controls matched by sex, age and region. All were interviewed about jobs and smoking. Those whose jobs suggested possible welding answered a welding questionnaire, and job-specific questions estimated asbestos exposure. Men who had held the job title "welder or burner" were 6% of cases and 2% of controls. After adjustment for smoking and asbestos the odds ratio was 1.93 (95% confidence limits 1.03 to 3.61). Any welding for at least half a year (28% of cases, 23% of controls) gave an adjusted odds ratio of 1.25 (0.94 to 1.65). More than 6,000 lifetime hours of oxyacetylene welding gave an unadjusted odds ratio of 1.86 (1.01 to 3.43). After adjustment this fell to 1.46 (0.72 to 2.96), which was not statistically significant. Men in the aircraft industry who had ever welded had an adjusted odds ratio of 2.29 (1.19 to 4.42). The authors concluded that some, but not all, of welders' excess risk may be due to smoking and occupational asbestos exposure. They noted that recalling asbestos exposure in hindsight is vulnerable to misclassification.

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: Case-control study with personal interviews about job and smoking histories
• Who was studied: 839 men with histologically or cytologically confirmed lung cancer, recruited from all hospitals in Bremen and two hospitals in Frankfurt, Germany, from August 1988 to August 1993. They were compared with 839 controls drawn at random from residents' registries and matched for sex, age and region. Response rates were 68.9% for cases and 68.1% for controls. 165 female cases were also enrolled, but the results reported are for men.
• Exposure: The main exposure was welding. A welding-specific supplementary questionnaire was given to each person whose job history suggested possible use of welding devices. Welding was measured in several ways: ever welding for at least half a year; lifetime hours of welding in general, of oxyacetylene or manual metal arc (MMA) welding, spot welding, flame cutting and gas-shielded welding; and years in the job title "welder or burner". Occupational asbestos exposure was estimated from job-specific supplementary questions in lifetime hours (never, less than 940, 940 to 5,280, more than 5,280) and was used as an adjustment factor. No asbestos fiber type is named.
• Main results:
  • Job title "welder or burner": 6% of cases and 2% of controls. The crude odds ratio was 2.65, reduced to 1.93 (95% CL 1.03 to 3.61) after adjustment for smoking and asbestos.
  • Any welding for at least half a year: 28% of cases and 23% of controls. The odds ratio was 1.25 (95% CL 0.94 to 1.65) after adjustment for smoking and asbestos.
  • Welding in general for more than 6,000 lifetime hours: odds ratio 1.45, reduced to 1.10 after adjustment for smoking and asbestos.
  • Oxyacetylene welding for more than 6,000 lifetime hours, unadjusted: odds ratio 1.86 (95% CL 1.01 to 3.43).
  • Oxyacetylene welding for more than 6,000 lifetime hours (17 controls, 30 cases), after adjustment for smoking and asbestos: odds ratio 1.46 (95% CL 0.72 to 2.96), not statistically significant.
  • Men who used oxyacetylene welding for at least 3 years, at least once a week, for at least 2 hours a day: odds ratio 2.77 (95% CL 1.20 to 6.38) after adjustment for smoking and asbestos (11 controls, 29 cases).
  • Oat cell carcinoma: the adjusted odds ratio for ever using oxyacetylene welding was 1.46 (95% CL 0.69 to 3.10).
  • Men employed in the aircraft industry who had ever welded: odds ratio 2.29 (95% CL 1.19 to 4.42) after adjustment for smoking and asbestos.
  • Occupational asbestos exposure of more than 5,280 lifetime working hours (84 controls, 124 cases): odds ratio 1.68, reduced to 1.47 (95% CL 1.04 to 2.07) after adjustment for smoking.
• The authors' conclusion: The authors concluded that the study supports the hypothesis that some, but not all, of the excess lung cancer risk of welders seen in earlier studies may be due to cigarette smoking and occupational asbestos exposure. They also concluded that oxyacetylene welding is associated with a moderately increased risk even after adjustment.
• Limitations the authors state:
  • Assessing asbestos exposure retrospectively is always vulnerable to misclassification.
  • The questions may not have properly distinguished mild steel welders from stainless steel welders.
  • Too few welders reported beryllium exposure to draw definite conclusions.
  • The study could not decide whether welding fumes or metal dusts are responsible for the excess risk.

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, Case-Control Study, Asbestos Exposure, Odds Ratio, Small Cell Lung Cancer.

Related studies

• Lung cancer risk and welding--preliminary results from an ongoing case-control study — K.H. Jöckel, W. Ahrens, et al. (1994)
• Occupational risk factors for lung cancer in women: results of a case-control study in Germany — I. Jahn, W. Ahrens, et al. (1999)
• Lung cancer and exposure to man-made vitreous fibers: results from a pooled case-control study in Germany — H. Pohlabeln, K.H. Jöckel, et al. (2000)
• Occupational lung cancer risk for men in Germany: results from a pooled case-control study — I. Brüske-Hohlfeld, M. Möhner, et al. (2000)
• Occupational asbestos exposure as a risk factor for laryngeal carcinoma in a population-based case-control study from Germany — H. Ramroth, W. Ahrens, et al. (2011)
• Occupational risk factors for lung cancer: a case-control study in West Germany — K.H. Jöckel, W. Ahrens, et al. (1998)

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