Smoking imputation and lung cancer in railroad workers exposed to diesel exhaust

Am J Ind Med. 2006 Sep;49(9):709-18. doi: 10.1002/ajim.20344.


Background: An association between diesel exhaust exposure and lung cancer mortality in a large retrospective cohort study of US railroad workers has previously been reported. However, specific information regarding cigarette smoking was unavailable.

Methods: Birth cohort, age, job, and cause of death specific smoking histories from a companion case-control study were used to impute smoking behavior for 39,388 railroad workers who died 1959-1996. Mortality analyses incorporated the effect of smoking on lung cancer risk.

Results: The smoking adjusted relative risk of lung cancer in railroad workers exposed to diesel exhaust compared to unexposed workers was 1.22 (95% CI = 1.12-1.32), and unadjusted for smoking the relative risk was 1.35 (95% CI = 1.24-1.46).

Conclusions: These analyses illustrate the use of imputation in record-based occupational health studies to assess potential confounding due to smoking. In this cohort, small differences in smoking behavior between diesel exposed and unexposed workers did not explain the elevated lung cancer risk.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Case-Control Studies
  • Cause of Death
  • Confounding Factors, Epidemiologic
  • Humans
  • Lung Neoplasms / epidemiology*
  • Male
  • Middle Aged
  • Occupational Diseases / epidemiology*
  • Occupational Exposure / adverse effects*
  • Railroads*
  • Retrospective Studies
  • Risk Factors
  • Smoking / epidemiology*
  • United States / epidemiology
  • Vehicle Emissions*


  • Vehicle Emissions