Black-White racial health disparities in inflammation and physical health: Cumulative stress, social isolation, and health behaviors.

Black Americans have vastly increased odds and earlier onsets of stress- and age-related disease compared to White Americans. However, what contributes to these racial health disparities remains poorly understood. Using a sample of 1577 older adults (32.7% Black; ages 55-65 at baseline), we examined whether stress, health behaviors, social isolation, and inflammation are associated with racial disparities in self-reported physical health. A latent cumulative stress factor and unique stress-domain specific factors were modeled by applying bifactor confirmatory analysis to assessments across the lifespan (i.e., childhood maltreatment, trauma exposure, discrimination, stressful life events, and indices of socioeconomic status). Physical health, health behavior, and social isolation were assessed using self-report. Interleukin-6 (IL-6) and C-reactive protein (CRP) were assayed from morning fasting serum samples; a z-scored inflammation index was formed across these 2 cytokines. A parallel serial mediational model tested whether race (i.e., Black/White) is indirectly associated with health through the following 3 independent pathways: (1) cumulative stress to preventative health behaviors (e.g., healthy eating) to inflammation, (2) cumulative stress to risky health behaviors (e.g., substance use) to inflammation; and (3) cumulative stress to social isolation to inflammation. There were significant indirect effects between race and self-reported physical health through cumulative stress, preventative health behaviors, and inflammation (B = -0.02, 95% CI: -0.05, -0.01). Specifically, Black Americans were exposed to greater cumulative stress, which was associated with reduced engagement in preventative health behaviors, which was, in turn, associated with greater inflammation and reduced physical health. A unique SES factor also indirectly linked race to physical health through preventative health behaviors. Cumulative stress exposure and unique aspects of socioeconomic status are indirectly associated with Black-White racial health disparities through behavioral (i.e., preventative health behavior) and biological (i.e., inflammation) factors. Culturally responsive evidence-based interventions that enhance engagement in preventative health behaviors are needed to directly confront health disparities. Ultimately, large scale anti-racist public policies that reduce cumulative stress burden (e.g., a living wage, universal healthcare) may best attenuate racial health disparities.