Neighborhood Racial and Ethnic Segregation and the Risk of Dementia in Older Adults Living with Kidney Failure
Authors: Li Yiting , Menon Gayathri , Long Jane J. , Chen Yusi , Metoyer Garyn T. , Wu Wenbo , Crews Deidra C. , Purnell Tanjala S. , Thorpe Roland J. , Hill Carl V. , Szanton Sarah L. , Segev Dorry L. , McAdams-DeMarco Mara A. 
Published: April 2024

Key Points

Regardless of race and ethnicity, older adults with kidney failure residing in or receiving care at dialysis facilities located in high-segregation neighborhoods were at a 1.63-fold and 1.53-fold higher risk of dementia diagnosis, respectively.Older adults with kidney failure residing in minority-predominant high-segregation neighborhoods had a 2.19-fold higher risk of dementia diagnosis compared with White individuals in White-predominant neighborhoods.

Background
Dementia disproportionately affects older minoritized adults with kidney failure. To better understand the mechanism of this disparity, we studied the role of racial and ethnic segregation (segregation hereafter), i.e., a form of structural racism recently identified as a mechanism in numerous other health disparities.

Methods
We identified 901,065 older adults (aged ≥55 years) with kidney failure from 2003 to 2019 using the United States Renal Data System. We quantified dementia risk across tertiles of residential neighborhood segregation score using cause-specific hazard models, adjusting for individual- and neighborhood-level factors. We included an interaction term to quantify the differential effect of segregation on dementia diagnosis by race and ethnicity.

Results
We identified 79,851 older adults with kidney failure diagnosed with dementia between 2003 and 2019 (median follow-up: 2.2 years). Compared with those in low-segregation neighborhoods, older adults with kidney failure in high-segregation neighborhoods had a 1.63-fold (95% confidence interval [CI], 1.60 to 1.66) higher risk of dementia diagnosis, an association that differed by race and ethnicity (Asian: adjusted hazard ratio [aHR] = 1.26, 95% CI, 1.15 to 1.38; Black: aHR = 1.66, 95% CI, 1.61 to 1.71; Hispanic: aHR = 2.05, 95% CI, 1.93 to 2.18; White: aHR = 1.59, 95% CI, 1.55 to 1.64; P
interaction < 0.001). Notably, older Asian (aHR = 1.76; 95% CI, 1.64 to 1.89), Black (aHR = 2.65; 95% CI, 2.54 to 2.77), Hispanic (aHR = 2.15; 95% CI, 2.04 to 2.26), and White (aHR = 2.20; 95% CI, 2.09 to 2.31) adults with kidney failure residing in minority-predominant high-segregation neighborhoods had a higher risk of dementia diagnosis compared with older White adults with kidney failure in White-predominant high-segregation neighborhoods. Moreover, older adults with kidney failure receiving care at dialysis facilities located in high-segregation neighborhoods also experienced a higher risk of dementia diagnosis (aHR = 1.53; 95% CI, 1.50 to 1.56); this association differed by race and ethnicity (P
interaction < 0.001).

Conclusions
Residing in or receiving care at dialysis facilities located in high-segregation neighborhoods was associated with a higher risk of dementia diagnosis among older individuals with kidney failure, particularly minoritized individuals.