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Chronic Obstructive Pulmonary Disease Mortality in Railroad Workers
  1. Jaime E Hart (jaime.hart{at}
  1. Harvard School of Public Health, United States
    1. Francine Laden (francine.laden{at}
    1. Harvard School of Public Health, United States
      1. Ellen A Eisen (eeisen{at}
      1. Harvard School of Public Health, United States
        1. Thomas J Smith (tsmith{at}
        1. Harvard School of Public Health, United States
          1. Eric Garshick (eric.garshick{at}
          1. VA Boston Healthcare System, United States


            Objective: There is little information describing the risk of non-malignant respiratory disease and occupational exposure to diesel exhaust.

            Methods: US railroad workers have been exposed to diesel exhaust since diesel locomotives were introduced after WWII and in a retrospective cohort study we examined the association of COPD mortality with years of work in diesel exposed jobs. To examine the possible confounding effects of smoking, multiple imputation was used to model smoking history. A Cox proportional hazards model was used to estimate an incidence rate ratio, adjusted for age, calendar year, and length of follow-up after leaving work (to reduce bias due to a healthy worker survivor effect).

            Results: Workers in jobs with diesel exhaust exposure had an increased risk of COPD mortality relative to those in unexposed jobs. Workers hired after the introduction of diesel locomotives had a 2.5% increase in COPD mortality risk for each additional year of work in a diesel exposed job. This risk was only slightly attenuated after adjustment for imputed smoking history.

            Conclusions: These results support an association between occupational exposure to diesel exhaust and COPD mortality.

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