Racial differences in cardiovascular disease morbidity and mortality are well established by middle age with African Americans contributing to higher rates of cardiovascular disease. In addition to traditional risk factors, African Americans experience greater exposure to stressful life events. Both an enhanced and a blunted hemodynamic reactivity to acute psychological stress have been associated with worse cardiovascular health status and may contribute to these disparities.
We studied 920 patients with stable coronary artery disease (CAD) and 109 controls without CAD. Systolic blood pressure (SBP), heart rate (HR), and rate-pressure product (RPP) were measured prior to, and following a public speaking stress task. We examined the association between race and hemodynamic reactivity to stress using mixed linear regression models adjusting for cardiovascular disease severity, medication usage and psychosocial, demographic and lifestyle factors.
Of the 920 patients (mean age 59 years), 39% were African American. African Americans had a more adverse socioeconomic and cardiometabolic profile (hypertension, diabetes, and body mass index) compared to white Americans. In response to mental stress, African American patients exhibited a lower increase in SBP (23 vs 27 mmHg; p <.0001), HR (11 vs 13 beats/minute; p =0.008) and RPP (3205 vs 3718 mmHg x beat/min; p =0.004) compared to white Americans, after adjusting for demographics, lifestyle and medical risk factors. Among controls (41% African American), there were no significant differences in hemodynamic reactivity to mental stress by race, and among CAD patients, there were also no differences in the hemodynamic reactivity to an exercise stress test by race.
African Americans with CAD exhibit a blunted hemodynamic response to mental stress compared to white Americans. Further research is needed to clarify the determinants of such differences and whether they contribute to race disparities in cardiovascular disease risk.