Perceived Discrimination and Trajectory of High-Sensitivity C-Reactive Protein: The Jackson Heart Study

Introduction: Perceiving discriminatory treatment against oneself may induce a stress response, and over time contribute to cardiovascular pathophysiology. The study evaluated the association of self-reported discrimination and changes in high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation predictive of incident cardiovascular disease. Hypothesis: We assessed the following hypotheses: 1) higher levels of perceived discrimination are associated with higher serum hs-CRP at baseline, 2) over 13 years of follow-up, greater mean increases in hs-CRP are observed among those with higher levels of baseline discrimination than those with lower levels of discrimination, and 3) body composition mediates the longitudinal trajectory. Methods: The sample included 5145 African American participants, aged 21-92, in the Jackson Heart Study. Multiple imputation addressed missingness in baseline sociodemographic (e.g, age, sex, education), behavioral (e.g., AHA smoking and physical activity categorizations) and clinical covariates (e.g, estimated glomerular filtration rate, diastolic blood pressure, hemoglobin A1c) as well as in hs-CRP taken at all three study examinations. Everyday, lifetime, and burden from perceived discrimination -attributed to reasons including race, gender, age, or weight- comprised primary predictors in three sets of multivariable linear regression models of baseline (2000-2004) discrimination and ln(hs-CRP). Linear mixed models (LMMs) were fitted to assess mean changes in ln(hs-CRP) between three study examinations (2000-2013).Mediation was quantified by percent changes in estimates adjusted for the adiposity measures BMI, waist circumference, or waist-to-height ratio. Results: In the cross-sectional analyses, those in the highest tertile of lifetime discrimination had adjusted ln(hs-CRP) levels 0.08 ln(mg/dL) lower than those in the lowest tertile (95% CI= -0.16, -0.01). However, the ln(hs-CRP) increases among those reporting more frequent everyday discrimination were 0.07 ln(mg/dL) higher per examination than those reporting no everyday discrimination (95% CI=0.01, 0.12) A similar trend emerged for lifetime discrimination and changes in ln(hs-CRP) (adjusted mean increase per visit: 0.04 ln(mg/dL), CI=0.01, 0.08). BMI, waist circumference, or waist-to-height ratio did not mediate the longitudinal associations between any discrimination measure and hs-CRP. In sensitivity analyses, the magnitude of these estimates did not change before or after multiple imputation. Conclusion: Everyday and lifetime discrimination were associated with significant hs-CRP increases over 13 years of follow-up. These conclusions build upon the existing research that indicates the physiological response to discrimination may lead to systemic inflammation and in turn cardiovascular disease.