Historical Estimation of Diesel Exhaust Exposure in a Cohort Study of Railroad Workers and Lung Cancer

Details

• Personal Author:
  Dockery DW ; Eschenroeder A ; Gagnon D ; Garshick E ; Jackson SL ; Laden F ; Smith, Thomas J. ; Speizer FE
• Description:
  Rationale: Although 95% of the locomotives in service in the US railroad industry were diesel by 1959, individual railroads transitioned from steam to diesel at different rates from 1945 to 1959. We hypothesize that accounting for these differences when modeling exposure will help characterize lung cancer risk attributable to diesel exhaust exposure in a cohort of 55,407 workers employed during this period and followed through 1996. Methods: We estimated the percent of diesel locomotives for each for the 95 largest railroads (93% of the cohort) using roster information and manufacturing data, and accounted for locomotive model using EPA emission factors and builder data. The railroad-specific diesel locomotive fraction for a given year was calculated, representing the probability of exposure in a specific year. Cumulative exposure (pre-1959) was defined for engineers/firemen and conductors/brakemen as the sum of the diesel fraction from 1945 to 1959. Results: The median diesel fraction was 8% in 1945 and 72% in 1952, the midpoint of the transition period. Rates of change from 25 to 75% diesel ranged from 1 to 12 years. The median adjusted cumulative exposure was 9.6 years (interquartile range 8.6-10.3). In analyses comparing each quartile of exposure with unexposed, the relative risks (RR) for the first three quartiles were all approximately 1.30, similar to the RR when exposure was modeled as a dichotomous variable (1.34). The RR for the fourth quartile was 1.43 (CI: 1.30-1.59). Conclusion: There was little variation in cumulative probability of pre-1959 exposure to diesel exhaust. Therefore, adjustment for railroad-specific rates of dieselization had little effect on lung cancer associations. [Description provided by NIOSH]
• Subjects:
  Carcinogens Lung Lung Diseases Mortality Neoplasms Occupational Health Railroads Respiratory System Respiratory Tract Diseases Safety Vehicle Emissions

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• Keywords:
  Cancer Diesel-emissions Diesel-engines Diesel-exhausts Exhaust-gases Lung-cancer Lung-disorders Mortality-data Mortality-rates Railroad-industry Respiratory-system-disorders

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• ISSN:
  1073-449X
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  Massachusetts ; OSHA Region 1
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  163
• Issue:
  5
• NIOSHTIC Number:
  nn:20035696
• Citation:
  Am J Respir Crit Care Med 2001 Apr; 163(5)(2)(Suppl):A717
• Federal Fiscal Year:
  2001
• NORA Priority Area:
  Work Environment and Workforce: Mixed Exposures
• Performing Organization:
  Harvard Medical School, Boston, Massachusetts
• Peer Reviewed:
  False
• Part Number:
  2
• Start Date:
  19990930
• Source Full Name:
  American Journal of Respiratory and Critical Care Medicine. Abstracts of the American Thoracic Society 2001 International Conference, May 18-23, 2001, San Francisco, California
• Supplement:
  Suppl
• End Date:
  20020929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:538934cd9f16d199bf32d793fd03f1dd6e6ed22e826c3ea53dce7fdb6ead498686c71100cd4206d05947a88f578bb3e95ce0fa48c7e7d08a93dca94128e96b72
• Download URL:
  https://stacks.cdc.gov/view/cdc/187472/cdc_187472_DS1.pdf
• File Type:
  [PDF - 266.86 KB ]