Adjustment for Suspected Misclassified Smoking Data in an Historical Cohort Study of Workers Exposed to AcrylonitrileDowning Zimmerman, Sarah (2014) Adjustment for Suspected Misclassified Smoking Data in an Historical Cohort Study of Workers Exposed to Acrylonitrile. Master's Thesis, University of Pittsburgh. (Unpublished)
AbstractObjectives: To examine the association between exposure to acrylonitrile (AN) and lung cancer mortality after properly addressing misclassification and possible positive confounding of smoking history. Methods: Subjects were 992 white males who were employed for three or more months between 1960 and 1996 at an AN chemical plant in Lima, OH. There were 15 identified cases of lung cancer deaths. Smoking histories were obtained for 90.3% of the cohort and 54.2% of the cohort were identified as having “ever smoked”. Though there were few “unknown” smoking histories, the smoking variable was determined to be misclassified as the RR for having ever smoked related to lung cancer was only 1.08 (95% CI=0.26, 6.18). We addressed potential confounding by smoking in the presence of suspected misclassified smoking data by determining if a reasonable adjustment of the available smoking data would change the risk levels of lung cancer in the original Lima cohort and the relationship between AN exposure and lung cancer using Monte Carlo simulation and bias adjustment. Conclusions: After running Monte Carlo simulation, we found that the mean RR of lung cancer mortality given differing levels of AN exposure decreased after adjusting for the simulated smoking data. However, the results from the bias adjustment must be interpreted with caution as the analysis was limited by the number of lung cancer cases. In this cohort, we concluded that smoking positively confounded the relationship between AN exposure and lung cancer mortality. Public Health Relevance: Properly adjusting for smoking history in studies of lung cancer is critical of the validity of the study results. As seen in this study, smoking habits impact the risk of certain health outcomes. Researchers must attempt to address the potential confounding by smoking whenever possible. Share
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