Structural racism, residential segregation, and exposure to trauma: The persistent impact of redlining.

Introduction: As part of New Deal era federal housing policy, the Home Owners' Loan Corporation (HOLC) developed maps grading US neighborhoods by perceived financial security. Neighborhoods with high concentrations of racial and ethnic minorities were deemed financially unstable and denied federal investment, a practice colloquially known as redlining. The aim of this study was to assess the association of historical redlining within Austin, Texas, to spatial patterns of penetrating traumatic injury.

Methods: A retrospective cross-sectional study was conducted using data from violent penetrating trauma admissions between January 1, 2014, and December 31, 2021, at the single Level 1 trauma center in Austin, Texas. Using ArcGIS, addresses where the injury took place were geocoded, and spatial joining was used to match them to their corresponding census tract, for which 1935 HOLC financial designations are classified as "Hazardous," "Definitely Declining," "Still Desirable," "Best," or "Non HOLC Graded." Tracts with designations of "Hazardous" and "Definitely Declining" were categorized as "Redlined." The adjusted incidence rate ratio comparing rates of penetrating trauma among historically "Redlined" versus "Not Redlined" and "Not Graded" census tracts was calculated.

Results: A total of 1,404 violent penetrating trauma admissions were identified for the study period, of which 920 occurred within the county of interest. Among these, 5% occurred in census tracts that were Not Redlined, 13% occurred in Redlined tracts, and 82% occurred in non-HOLC graded tracts. When adjusting for differences in current census tract demographics and social vulnerability, historically Redlined areas experienced a higher rate of penetrating traumatic injury (Not Redlined injury rate ratio, 0.42; 95% confidence interval, 0.19-0.94; p = 0.03; Not Graded injury rate ratio, 0.15; 95% confidence interval, 0.07-0.29; p < 0.001).

Conclusion: Neighborhoods unfavorably classified by HOLC in 1935 continue to experience a higher incidence rate of violent penetrating trauma today. These results underscore the persistent impacts of structural racism and of historical residential segregation policies on exposure to trauma.

Level Of Evidence: Prognostic and Epidemiological; Level III.