title: Lung cancer risk in welders and foundry workers with a history of heavy smoking in the USA: The National Lung Screening Trial.
abstract: 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.
  
  
  
  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.
  
  
  
  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)).
  
  
  
  Our findings provide further evidence that exposure to welding/metal fumes may be associated with elevated lung cancer risk.
  
  
  
  NCT00047385.
authors.affiliation: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, Maryland, USA.
authors.forename: Jason Y Y
authors.initials: JYY
authors.lastname: Wong
authors.affiliation: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, Maryland, USA.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Bassig
authors.affiliation: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, Maryland, USA.
authors.forename: Wei Jie
authors.initials: WJ
authors.lastname: Seow
authors.affiliation: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, Maryland, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.affiliation: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, Maryland, USA.
authors.forename: Bu-Tian
authors.initials: BT
authors.lastname: Ji
authors.affiliation: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, Maryland, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Blair
authors.affiliation: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, Maryland, USA.
authors.forename: Debra T
authors.initials: DT
authors.lastname: Silverman
authors.affiliation: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Rockville, Maryland, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Lan
mesh_terms: D000368:Aged; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008670:Metals / Q000009:adverse effects; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced* / Q000453:epidemiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D016016:Proportional Hazards Models; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D011795:Surveys and Questionnaires; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D014896:Welding
chemical_list: D000395:Air Pollutants, Occupational; D008670:Metals
keywords: Foundry Work; Lung Cancer; Metal; National Lung Screening Trial