Causal models for addressing healthy worker effect in occupational cohort studies

Details

• Personal Author:
  Chevrier J ; Eisen EA
• Description:
  Individuals who are hired and remain at work longer are generally healthier than those who are unemployed or leave work, causing downward bias in studies of the health effects of occupational exposures. We present results from a study of ischemic heart disease mortality in a cohort of autoworkers exposed to metalworking fluid (MWF) using two approaches designed to reduce the bias. MWF is a mixed particulate containing metals and polyaromatic hydrocarbons and although previous studies of this cohort have found associations with selected cancers, this is the first investigation of heart disease. The cohort includes all workers hired between 1938 and 1981 who worked more than 3 years in one of three automobile manufacturing plants in Michigan (N = 39,927). The cohort was followed-up for vital status from 1941 to1995, and cause of death was ascertained from state health records and the National Death Index. Date of birth, race, gender and work history, including time off work, were obtained from company records. Annual exposure to oil-based MWF was treated as binary and health status was defined as the time off work in every year of follow up. To adjust for time off work as a time-varying confounder, we used two causal modeling approaches: Marginal Structural Models with Inverse Probability of TreatmentWeights (IPTW) and Structural NestedModels using g-estimation. We compared these results based on 2,725 heart disease deaths, with those from a standard Cox model. Finally, we applied the same three approaches to examine MWF exposure in relation to all causes of death combined and all cancers combined in order to examine the hypothesis that bias due to healthy worker effect is stronger for chronic diseases, such as heart disease, than for cancer. [Description provided by NIOSH]
• Subjects:
  Automobiles Demography Metals Minerals Morbidity Mortality Occupational Health Safety Workplace
• Keywords:
  Automotive-industry Cutting-oils Demographic-characteristics Diseases Exposure-levels Metal-compounds Metallic-compounds Morbidity-rates Mortality-rates Oils Statistical-analysis Work-environment Worker-health Workers

  More +
• ISSN:
  0002-9262
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  169
• NIOSHTIC Number:
  nn:20045285
• Citation:
  Am J Epidemiol 2009 Jun; 169(Suppl):S41
• Federal Fiscal Year:
  2009
• Performing Organization:
  University of California, Berkeley
• Peer Reviewed:
  False
• Start Date:
  20070801
• Source Full Name:
  American Journal of Epidemiology
• End Date:
  20110731
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:d235f6fe759e3b3d42dbe9d342d295f08d2f1005fd654b2321ed3b27c1f2552157df7c1b5f03a27eae6a6c3228e683403c1bc0c61193fafe23dad9682f53041b
• Download URL:
  https://stacks.cdc.gov/view/cdc/200750/cdc_200750_DS1.pdf
• File Type:
  [PDF - 34.38 KB ]