59 Racialized Economic Segregation and Insurance Disadvantage as Mediators of Racial Disparities in Breast Cancer Stage at Diagnosis

Background

Black women in the United States experience disproportionately high mortality from breast cancer, driven in part by more advanced disease stage at diagnosis. Structural racism and health insurance disadvantage may be important mediators of more advanced disease stage in Black women with breast cancer.

Materials and Methods

This study obtained data from the Florida Cancer Data System for women who were diagnosed with breast cancer from 2013 to 2021. A proxy for the effects of structural racism was obtained by using the racial-ethnic-income version of the Index of Concentration at the Extremes (ICE; mediator 1). At the census tract level, ICE scores were calculated, and women were categorized into quintiles ranging from the most- to least-deprived neighborhoods. Health insurance disadvantage was defined as having Medicaid, being uninsured, or having unknown insurance status (mediator 2). Poisson regression with least squares means was used to assess the adjusted likelihood of living in the most deprived ICE quintile and having insurance disadvantage for Black and White women. Causal mediation analyses using the g-formula were used to obtain the total effect (TE), natural direct effect (NDE), and natural indirect effect (NIE) of race on advanced disease stage. Age, region of the state, and marital status were considered as confounders in all models.

Results

Black women were more likely to live in the most disadvantaged neighborhoods (41.6% vs 9.6%) and to experience insurance disadvantage (9.5% vs 6.9%). In mediation analyses, the predicted risk of advanced disease was 35.7% for Black women vs 27.9% for White women. On the prevalence difference scale, the following measures were obtained: TE equaled 7.8%, NDE equaled 5.5%, and NIE equaled 2.3%. On the prevalence ratio scale, the following measures were obtained: TE equaled 1.28, NDE equaled 1.20, and NIE equaled 1.07. The ICE and insurance status explained 29% of the racial disparity in advanced disease stage at diagnosis.

Conclusions

These findings demonstrate that structural racism and insurance disadvantage account for a meaningful but incomplete portion of racial disparities in breast cancer stage at diagnosis. To achieve more equitable breast cancer outcomes, additional research is needed to understand the multifactorial causes of racial disparities in disease stage at diagnosis for women with breast cancer.