Health Outcomes Seminar: "Causal Mediation Analyses to Understand Socioeconomic Factors and Cancer Health Disparities: Racial Differences in Treatment of Diffuse Large B-Cell Lymphoma"
Most epidemiologic studies account for socioeconomic status (SES) by modeling it as a confounder or an effect modifier when examining the relationship between racial disparities and cancer treatment or mortality. A confounder is defined as a characteristic associated with both the exposure and the outcome, though not in the causal pathway. We hypothesize that race and ethnicity may determine or predict SES measures and therefore consider SES measures to be potential mediators in a causal pathway between race/ethnicity and cancer treatment disparities. Incorporating a mediator as a confounder in statistical modeling can bias effect estimates by mis-specifying or possibly over adjusting the model, which could explain conflicting findings and interpretations of observational studies. The purpose of our study was to conduct causal mediation analyses examining associations between race and ethnicity and receipt of chemo-immunotherapy among elderly diffuse large B-cell lymphoma patients with potential mediation by patient- and community-level SES variables: (i) having Medicare private supplementation; (ii) metropolitan statistical area of residence; and (iii) census-tract poverty level.