Mediators of county-level racial and economic privilege in cancer screening

Area-level social determinants of health (SDoH) impact access to cancer care and prevention. Little is known about the factors that underlie the impact of residential privilege on county-level cancer screening uptake.

Population-based cross-sectional study examining county-level data was obtained from the Centers for Disease Control and Prevention's PLACES database, American Community Survey and the County Health Rankings and Roadmap database. The Index of Concentration of Extremes (ICE), a validated measure of racial and economic privilege, was examined relative to county-level rates of US Preventive Services Task Force (USPSTF) guideline-concordant screening for breast, cervical, and colorectal cancers. Generalized structural equation modeling was used to determine the indirect and direct effects of ICE on cancer screening uptake.

Across 3142 counties, county-level cancer screening rates demonstrated geographical variation ranging from 54.0% to 81.8% for breast cancer screening, from 39.8% to 74.4% for colorectal cancer screening, and from 69.9% to 89.7% for cervical cancer screening. Of note, cancer screening rates for breast, colorectal, and cervical cancer all increased from lower (ICE-Q1) to higher (ICE-Q4) privileged areas (breast: Q1 = 71.0% vs. Q4 = 72.2%; colorectal: Q1 = 59.4% vs. Q4 = 65.0%; cervical: Q1 = 83.3% vs. Q4 = 85.2%; all p < 0.001). Mediation analysis revealed that the observed disparities between ICE and cancer screening uptake were explained by mediators such as poverty status, lack of health insurance or employment, urban-rural location and access to primary care physicians that accounted for 64% (95% confidence interval [CI]: 61%-67%), 85% (95% CI: 80%-89%), and 74% (95% CI: 71%-77%) of the effect on breast, colorectal, and cervical cancer screening, respectively.

In this cross-sectional study, the association between racial and economic privilege on USPSTF-recommended cancer screening was complex and influenced by an interplay of sociodemographic, geographical, and structural factors. Understanding the underlying area-level SDoH that mediate disparities in cancer prevention strategies can help focus interventions to improve equity in cancer prevention.