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Is segregation bad for your heart?: A natural experiment for residential racial segregation exposure in childhood and cardiovascular disease Gabriel Schwartz* Gabriel Schwartz Schwartz Drexel University
Background: Residential racial segregation is hypothesized to be a driver of inequities in cardiovascular disease. A key manifestation of structural racism, residential segregation stratifies access to healthcare, education, food, and employment, as well as discretionary law enforcement and targeting for harmful product marketing. Yet despite ample cross-sectional data, little work has examined (A) the long-term implications of childhood residential segregation exposure for CVD, especially (B) using causal designs. Here, we use quasi-random urban planning decisions made by Northern cities prior to the Great Migration as an instrument for segregation as Black families moved to the North in search of opportunity, providing a natural experiment for the causal impact of childhood segregation exposure on CVD.
Methods: We followed Ananat’s work identifying the degree to which early 1900s railway systems gridded cities as a valid instrument. We linked her data on segregation and train tracks to where participants in the Panel Study of Income Dynamics were born (1968-1994, n=829 Black & 1,262 White) and followed them through 2023. We fit race-stratified accelerated failure time models with an instrumental variables design and using a cluster bootstrap. Models controlled for parental socioeconomic status at birth.
Results: Given their distribution across PSID study cities, our instrument was stronger for White than Black participants. Point estimates for White (survival ratio = 1.16, 95% CI=1.02,1.75) and Black (SR = 0.67, 95% CI=0.29,5.10) participants suggest that childhood residential segregation exposure causally delays the onset of CVD for White individuals but speeds it up for Black individuals, though confidence intervals for our Black sample were uninformatively wide.
Conclusion: Segregation harms Black US Americans’ heart health while protecting White US Americans, though larger studies are needed to estimate precise causal effects for Black communities.