LAUSR

BACKGROUND Neighborhood-level racial residential segregation has been linked to several cardiovascular disease risk factors and outcomes in Black adults, but its impact on subclinical atherosclerosis remains unknown. In addition, although the impact of segregation on health may vary over the life course, most studies have examined segregation exposure at a single point in time. This article takes a life course approach by examining associations of exposure to neighborhood-level racial residential segregation in young adulthood and patterns of exposure from young adulthood to midlife with coronary artery calcification (CAC) incidence. METHODS We used data on 1125 Black CARDIA study (Coronary Artery Risk Development in Young Adults) participants free of CAC. Residential segregation was assessed using the Gi* statistic and measured when participants were young adults (18-30 years old, in 1985-1986) and as the pattern from young adulthood to midlife (15 years later). Poisson regression with generalized estimating equations models was used to measure CAC incidence. RESULTS We found participants living in low segregation neighborhoods in young adulthood had 0.52 (rate ratio [95% CI: 0.28-0.98]) times lower risk of developing CAC compared with high segregation after adjusting for young adulthood sociodemographic characteristics and neighborhood poverty. Associations were attenuated and no longer statistically significant with adjustment for midlife CAC risk factors hypothesized to be on the causal pathway (rate ratio: 0.56 [95% CI: 0.29-1.09]). Findings for patterns of segregation over time suggest participants living in low segregation neighborhoods in young adulthood were less likely to develop CAC than those who started out in medium/high segregation neighborhoods, regardless of where they lived in midlife (rate ratio for increase from low to medium/high: 0.42 [95% CI: 0.19-0.95]; rate ratio for continuously low versus continuously medium/high segregation neighborhoods: 0.75 [95% CI: 0.31-1.83]). CONCLUSIONS We found that participants living in more segregated neighborhoods in young adulthood were more likely to develop CAC due at least in part to differences in CAC risk factor burden accumulated over follow-up.