Comparison of standard methods with G-estimation of accelerated failure-time models to address the healthy worker survivor effect

Details

• Personal Author:
  Chevrier J ; Eisen EA ; Picciotto S
• Description:
  Background: Studies of autoworkers report associations between exposure to straight metalworking fluids (MWF) and cancer mortality. Previous studies, however, have not addressed the healthy worker survivor effect (HWSE). Several methods have been proposed but none consider that this bias may be caused by time-varying confounders affected by prior exposure. G-estimation of accelerated failure-time models was developed to address this issue but was never applied to account for the HWSE. Methods: We apply g-estimation of accelerated failure time models to estimate hazard ratios for chronic obstructive pulmonary disease (COPD), heart disease, and selected cancers in relation to straight MWF exposure in 38,747 autoworkers. We compare results with those from standard Cox-based methods previously proposed to address the HWSE. We expand our analysis by using a series of binary variables to capture the change in effect with increasing exposure concentration. Results: Standard methods suggest that exposure to straight MWF has a null or protective effect for mortality from all causes combined, all cancers combined, COPD, and heart disease. In contrast, results using g-estimation suggest that exposure may be causally related to these outcomes. Analysis of specific cancer sites by g-estimation also suggested increased mortality risk for lung cancer. Conclusion: Bias may arise because health status is associated with mortality, determines future exposure and is predicted by past exposure. G-estimation accounts for health status being both a confounder and possibly an intermediate variable between exposure and disease. This method may thus provide a better control for the HWSE than standard methods. [Description provided by NIOSH]
• Subjects:
  Automobiles Cardiovascular Diseases Cardiovascular System Lung Metals Morbidity Mortality Neoplasms Occupational Health Respiratory System Respiratory Tract Diseases Risk Assessment Risk Factors Safety Workplace

  More +
• Keywords:
  Automotive-industry Cancer Cardiopulmonary-system Cardiopulmonary-system-disorders Cardiovascular-system Cardiovascular-system-disease Exposure-levels Metalworking-fluids Models Morbidity-rates Mortality-rates Pulmonary-system Pulmonary-system-disorders Risk-factors Work-environment 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:
  173
• NIOSHTIC Number:
  nn:20045665
• Citation:
  Am J Epidemiol 2011 Jun; 173(Suppl 11):S231
• Federal Fiscal Year:
  2011
• Performing Organization:
  University of California, Berkeley
• Peer Reviewed:
  False
• Start Date:
  20070801
• Source Full Name:
  American Journal of Epidemiology
• Supplement:
  11
• End Date:
  20110731
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:3dd7fa7aeae1db20005b34974722c909a2a63789a21f9f5f8cc517483adb4090b901d01935209cce148d7a380d19ea8ac1b63d633386f6ce200a300eabf4cc7f
• Download URL:
  https://stacks.cdc.gov/view/cdc/201008/cdc_201008_DS1.pdf
• File Type:
  [PDF - 47.48 KB ]