Objectives Foundry work is a risk factor for lung cancer; however, the association with welding is unclear, as smoking is common among metalworkers and may mask the relationship. We evaluated whether history of welding and foundry work, independently and jointly, and employment duration were associated with lung cancer risk in heavy smokers.
Methods We analysed data from the National Lung Screening Trial, a prospective randomised trial of 53 454 heavy smokers (>30 pack-years) in the USA. Cox regression models were used to estimate the HRs and 95% CIs of medically/histologically confirmed incident lung cancer during the follow-up period (2002–2009) in relation to history and duration of welding and foundry work assessed via questionnaires, adjusted for screening arm, component study, sex, age, race/ethnicity, education, smoking status and pack-years, body mass index and personal/family medical history.
Results There were 2034 incident lung cancer cases throughout the follow-up. Increasing years of employment in welding (p-trend =0.039) and foundry work (p-trend =0.005) were related to increased lung cancer risk among heavy smokers. Having ever been employed (≥1 yr) as either a welder or foundry worker alone was associated with non-significant increased risks of lung cancer (HR=1.12 (95% CI 0.91 to 1.37) and HR=1.09 (95% CI 0.85 to 1.39), respectively). Further, there was a joint-effect in that those who were ever employed in both occupations had significantly increased risks (HR=1.48 (95% CI 1.08 to 2.04)).
Conclusions Our findings provide further evidence that exposure to welding/metal fumes may be associated with elevated lung cancer risk.
Trial registration number NCT00047385.
- Foundry Work
- Lung Cancer
- National Lung Screening Trial
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Contributors All authors contributed equally to the design, analysis, interpretation and manuscript composition for this study.
Funding The ClinicalTrials.gov identifier for NLST is NCT00047385. The Lung Screening Study (LSS) sites of the NLST were funded through contracts with the Early Detection Research Group and Biometry Research Group, Division of Cancer Prevention: University of Colorado Denver (N01-CN-25514), Georgetown University (N01-CN-25522), Pacific Health Research and Education Institute (N01-CN-25515), Henry Ford Health System (N01-CN-25512), University of Minnesota (N01-CN-25513), Washington University in St. Louis (N01-CN-25516), University of Pittsburgh (N01-CN-25511), University of Utah (N01-CN-25524), Marshfield Clinic Research Foundation (N01-CN-25518), University of Alabama at Birmingham (N01-CN-75022), Westat (N01-CN-25476) and Information Management Services (N02-CN-63300). The American College of Radiology Imaging Network (ACRIN) was supported by grants under a cooperative agreement with the Cancer Imaging Program, Division of Cancer Treatment and Diagnosis (U01-CA-80098 and U01-CA-79778).
Competing interests None declared.
Patient consent Obtained.
Ethics approval Each of the 33 screening centres from this list obtained their own respective IRB approval: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3009383/table/t04/
Provenance and peer review Not commissioned; externally peer reviewed.