Black men have overall age-adjusted rates of cancer incidence and mortality that are higher than any other U.S. population group. Findings from the 1996 Report on the National Occupational Research Agenda suggest that unidentified race-specific occupational risk factors for cancer may be important contributors to this disparity. An excess of occupational cancers among minorities is further underscored by a review revealing elevated non-white to white cancer mortality ratios in the majority of studies reporting any race-specific increases, with the greatest racial disparity evident for hematolymphopoietic cancers. Data are sparse, however, on race-specific etiologic determinants. Moreover, published reports have generally been based on data from death certificates and other secondary sources that are of questionable validity because of racial disparities in accuracy. To address this information gap, the proposed project will use secondary data from the Selected Cancers Study (SCS) to investigate race-specific occupational risk factors for non-Hodgkin lymphoma (NHL), Hodgkin disease (HD), and soft tissue sarcoma (STS). The SCS was a large U.S. population-based case-control study conducted in the mid-1980s to examine associations between exposure of military troops to the defoliant herbicide Agent Orange during the Vietnam War and subsequent risk of these cancers. The study population comprised nearly 6,000 men aged 30 to 60 years, the majority of whom were directly interviewed. Study participants were asked about every full- and part-time job held for greater than or equal to 1 year since age 18. For each job, participants were queried about job title, main duties, type of business or industry, year job was started, and year job was ended; all responses were coded verbatim. In an analysis using dichotomous occupational exposure data from the SCS, we identified striking increases in risk of NHL, HD, and STS among Black men exposed to chromium or wood dust, whereas no risk factors were found for Whites.
One aim of this project will be to extend the preliminary analysis to investigate dose-response relations.
A second aim will be an extension of that analysis to investigate risk factors among Hispanic men. A third project aim will be to examine race-specific dose-response associations for cancer risks in relation to occupational chlorophenol exposures and agricultural vs. non-agricultural herbicide exposures.
A fourth aim will be to explore race- and cancer-specific risk factors based on Standard Occupational Codes and Standard Industry Codes. Because the SCS database includes detailed occupational information for a study population large enough to provide substantial power to detect race-specific occupational cancer risk factors, it provides a unique and cost-effective opportunity to identify preventable risk factors that may be contributing to racial disparities in cancer incidence and mortality.
