Abstract C005: Social determinants and environmental exposures and their localized contribution to risk of cancer mortality

Abstract

Abstract When considering environmental exposures and/or social determinants of health (SDOH), data are typically available by counties, zip codes or census tracts. We consider two quantitative challenges in this setting when modeling cancer outcomes. The first is that multiple, potentially highly correlated exposures may contribute to risk. The second is that the spatial correlation of such features may not follow the original models designed for disease risk mapping. While several conditional autoregressive (CAR) models are typically utilized (Besag et al. (1991), Leroux et al. (1999), Stern and Cressie (1999)), a critical drawback is that they impose a global level of autocorrelation across the study area, presuming areas nearest each other are most similar. Spatial data may actually include step changes in the risk surface, indicative of more complex patterns either due to physical barriers and/or social isolation. Thus, identifying these step changes is of interest, as they may reflect the underlying complexity of the relationship between environmental exposures, SDOH and cancer mortality. We consider a two-step model to explore how clusters of environmental exposures and SDOH may be able to identify boundaries in the risk surface of cancer outcomes. In the first step, we estimate clusters of exposures using Bayesian profile regression, a nonparametric approach based on Dirichlet process mixture methods. In the second step, we model cancer mortality using locally adaptive spatial smoothing with the clusters as dissimilarity metrics (Lee and Mitchell, 2012). Several diagnostic tools are used to assess convergence in each step. With this work, we bridge the gap between incorporating mixtures of correlated exposures with the identification of localized areas with elevated risk of cancer mortality. We apply this approach to a nationwide database of county-level breast cancer mortality, utilize environmental exposure data from the National Air Toxics Assessment and assess SDOH from the American Community Survey. Citation Format: Kara McCormack. Social determinants and environmental exposures and their localized contribution to risk of cancer mortality [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C005.