This study of asymptomatic U.S. adults of different racial/ethnic identity is the first to our knowledge to support the association between experiencing racial discrimination and an increased risk of coronary artery calcification, a marker for atherosclerosis. Our results contradict two other studies that have investigated the influence of racial discrimination or unfair treatment and subclinical atherosclerosis[28, 36]. Both previous studies were restricted to women and both found that "everyday" discrimination was associated with subclinical coronary artery disease, measured by coronary calcium  and intima-media thickness, although one reported the association only among African American females and the relationship was not statistically significant. However, when both studies restricted this association to racial discrimination, the association was no longer apparent. The authors concluded that it is not the attribution of discrimination but the experience of chronic discrimination that influences CAC. Neither study assessed how response to unfair treatment modified the association between self-reported discrimination and sub-clinical atherosclerosis. Our findings parallel studies that have found discrimination to be associated with hypertension among those who passively respond, or internalize their response, to unfair treatment[9, 16, 17]. Hence, it appears that coping mechanisms, such as speaking out in response to racist events, mitigates the impact of racial discrimination on CAC. These results remained significant after adjusting for smoking status and BMI and suggest future interventional studies are needed that empower individuals and communities to address and respond to everyday inequalities.
Several potential mechanisms linking psychosocial stressors such as self-reported discrimination to the development of coronary artery calcified plaque have been proposed. Inflammatory induction is a pathophysiologic process that may be mediated by psychosocial stressors. Emerging evidence indicates that CVD development may involve the release of cytokines such as interleukin-6 and tumor necrosis factor α in an inflammatory response to epithelial damage stimulated by acute stressors. Other possible mechanisms involve adverse health behaviors such as smoking, alcohol consumption, or poor diet in response to stress, which may contribute to risk, although our results found several of these factors (i.e., smoking, and BMI) did not account for all of the adverse effect from racial discrimination.
The strengths of this study include the use of a validated instrument to measure discrimination and response to unfair treatment, the inclusion of multiracial/ethnic asymptomatic adults, and the use of the MSCT scan to detect coronary calcification. However, our results are subject to a number of limitations. We attempted to measure cumulative discrimination by determining whether participants ever experienced racial discrimination, although it is possible that recall may not be complete. In addition, we did not measure discrimination attributable to other characteristics, such as gender. The cross-sectional nature of the study precludes any statements about causal associations.
Previous research has confirmed that the experience of discrimination or unfair treatment may act as a stressor and that the appraisal of stress may also be important to measure[18, 20]. Future investigations should include measures of discrimination attributed to multiple characteristics, whether psychosocial factors are intermediate factors in this association, and the moderating effects of coping resources. Potential variation by gender, race, and level of educational attainment should also be incorporated. Finally, the measure of discrimination investigated should reflect a lifecourse perspective and account for cumulative experiences of unfair treatment that may influence the disease process since atherosclerosis develops over an extended period. Moreover, factors that may impact how self-reported and perceived racism is reported should be examined. Variations on how one interprets discrimination, whether due to social status, geographic variation, or personal history, may affect how discrimination is measured. For example, one study was able to extract thoughts or reports of past racist events among its participants only when they went into in-depth discussions. Also, types of racist experiences in society have changed over time from more overt events to more subtle ones , such as suppression in social status and its impact on home ownership or higher educational opportunities.