Occupational Chemical Exposure Assessment in a Brain Cancer Case-Control Study

Details

• Personal Author:
  Shimek JAM
• Description:
  This dissertation titled "Occupational Chemical Exposure Assessment in a Brain Cancer Case-Control Study" documents three projects exploring the association between the potential exposure to known of suspected animal neurocarcinogens (ANCs) found in the workplace and the incidence of brain cancer, specifically, glioma. The data used in this study were obtained from a case-control study of glioma. This study was divided into two phases, a pilot study and the main study. Pilot study data were used to complete the first project. Study participants in the pilot study provided hand written self-reported work histories. Each of the study participant's jobs was coded for industry using the Standard Industry Classification System (SIC) and occupation using the Standard Occupation Classification System (SOC) based on the work history. Members of the research group completed an extensive literature search and compiled a list of more than 40 known or suspected animal neurocarcinogens. This list was narrowed to 18 chemicals found in the workplace as identified by the National Institute for Occupational Safety and Health (NIOSH) during the completion of the National Occupational Exposure Survey (NOES), 1981-83. The NOES was similarly coded for industry and occupation and the work histories compared to the NOES to develop a cumulative exposure score. Cumulative exposure scores were generated for each study participant based on the 18 chemicals, their work history and an exposure intensity factor based on occupation within the industry of their jobs. The results of the pilot study data analyses demonstrated that a cumulative exposure score could be developed from the work histories; however, all industries and/or occupations were not surveyed by the NOES and only 41% of all jobs could be scored for potential exposure. The association between the cumulative exposure score and case/control status was examined by calculation of odds ratios for matched pair analyses using all controls, only sibling controls and only friend controls and a frequency matched pair, as well as unmatched cases and controls. Odds ratios indicated a non-significant association with reduced odds between cases and controls. Analyses of individual industries, occupations and chemical (ever versus never exposed) showed slightly elevated odds ratios. The second project utilized main study data. Study participants were asked a series of questions concerning the industries and occupations where they had worked, which were targeted to evaluate potential exposure to specific ANCs. From the responses to the questions provided by study participants, potential exposure to acrylamide, 1,3-butadiene and polycyclic aromatic hydrocarbons were evaluated for cases and controls. Odds ratios were again calculated to evaluate the association between case/control status and industry, occupation or chemical. These results indicated statistically significant reduced risk of glioma based on potential workplace exposure to these chemicals. The third project was a biomarker study. Hemoglobin adducts are biomarkers that indicate that an exposure to a specific chemical has occurred. In this study, a subset of the control population of either the pilot or main studies provided blood samples which were analyzed to detect exposure to 1,3-butadiene and acrylamide. The control population was used to avoid any interference from treatments the cases may have received. The study was intended to show an association between potential exposure to the chemicals as indicated by the SIC code of their current job and the reported hemoglobin adduct concentrations. However, the study was small and a majority of participants were either retired or working in an industry not surveyed by NIOSH. Therefore, there either was no potential exposure or the exposure could not be determined. Hemoglobin adduct results were also compared to available demographic, smoking and diet variables. When comparing study participants who resided in Southern states to those living in Northern states the difference between the geometric means of the hemoglobin adducts for the joyr-Val were higher and statistically significant. Statistically significant differences between smokers and non-smokers and ever smokers and never smokers were also statistically significant for the acrylamide adduct results. Study participants reported the frequency of consumption of several foods as part of the diet history questionnaire. The resulting data were combined for analyses of the various question responses and were suggestive of an association but not statistically significant for most of the geometric mean comparisons. A comparison of the responses to the question regarding the frequency of consumption of corn, wheat and millet products indicated a statistically significant difference in the geometric means for the glycidamide adduct based on the frequency of consumption. Hemoglobin adduct results were not associated with the potential for exposure to either acrylamide or 1,3- butadiene. The study does report the first human detection of the pyr-Val hemoglobin adduct to 1,3-butadiene. The epoxide that forms the pyr-Val hemoglobin adduct is the most mutagenic of the three possible epoxides formed by 1,3-butadiene metabolism. Acrylamide adduct formation was comparable to the results recently published in the Fourth National Report on Human Exposures to Environmental Chemicals. Collectively, these three projects demonstrate the need for improved exposure assessment methods including the sharing of available qualitative data, such as personal sampling data, to better predict potential exposures to ANCs. Collaboration between epidemiology and exposure assessment fields with additional quantitative data such as biomarker data will continue to refine the exposure assessment process. [Description provided by NIOSH]
• Subjects:
  Biomarkers Carcinogens Diet Hydrocarbons Occupational Exposure Occupational Health Polycyclic Aromatic Hydrocarbons Risk Assessment Risk Factors Safety
• Keywords:
  1,3-Butadiene Acrylamide Brain Cancer Chemicals Exposure Assessment Occupational Exposure Polycyclic Aromatic Hydrocarbons Risk Factors
• ISBN:
  9781124309149
• Publisher:
  ProQuest LLC.
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Dissertation
• Place as Subject:
  Illinois ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20059343
• Citation:
  Ann Arbor, MI: ProQuest LLC., 2010 Nov; :3431376
• CAS Registry Number:
  1,3-Butadiene (CAS RN 106-99-0) ; Acrylamide (CAS RN 79-06-1)
• Federal Fiscal Year:
  2011
• NORA Priority Area:
  Agriculture, Forestry and Fishing
• Performing Organization:
  University of Illinois at Chicago
• Peer Reviewed:
  False
• Start Date:
  20090901
• Source Full Name:
  Occupational chemical exposure assessment in a brain cancer case-control study
• End Date:
  20100831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:997b0179dcb6809510e9dcbd1cdb5a4cc293d803200c13419d1fed37eb31326b4fae79e4d935047b03ed2e47e93b715ee02fa818133e17d24f2042624df9f050
• Download URL:
  https://stacks.cdc.gov/view/cdc/223607/cdc_223607_DS1.pdf
• File Type:
  [PDF - 4.42 MB ]