Residential segregation and late-stage colorectal cancer in the United States: a population-based study of 1.2 million adults

We examined the association between residential segregation and late-stage colorectal cancer (CRC) in the United States. The restricted-use United States Cancer Statistics database was used to identify all CRC cases diagnosed during 2009-2017. Late-stage CRC was determined according to the presence of distant involvement of the tumor at diagnosis. Residential segregation was measured at the county level by the Index of Concentration at the Extremes based on income, race/ethnicity and its combination, using the 2013-2017 American Community Survey data. Multilevel logistic regression models accounting for clustering at counties were fit. Analyses were stratified by race/ethnicity, sex and age. Overall, patients residing in counties with a high concentration of least advantaged residents had increased odds of late-stage CRC compared to their counterparts residing in counties with a high concentration of most advantaged people. These findings were observed on all measures of residential segregation, with clear gradients for economic and racialized economic segregation. In stratified analyses, stronger associations were observed among racial/ethnic minoritized people and younger age groups; results did not differ by sex. These findings underscore the role of institutionalized racism as a contributor to health inequities, such that laws and policies driving residential segregation may impact timely preventive care.