Abstract P180: A Racial Comparison of Vascular Hemodynamics in Middle-aged Americans: The Jackson Heart Study

Background: Despite the higher rates of hypertension and cardiovascular disease (CVD) sequela due to hypertension in African Americans (AA), literature on the hemodynamic factors contributing to vascular stiffness is sparse in this high risk population. Objective: We investigated the hemodynamics of vascular stiffness and its components in a middle-aged cohort of AA using arterial tonometry and compared findings to what has been seen in a healthy cohort of non-Hispanic whites from Framingham. Methods: Noninvasive hemodynamic factors were measured in 1,750 Jackson Heart Study participants (68±11 years, 65% female). A healthy reference group from published work in Framingham was used to determine the prevalence of abnormals in the Jackson Heart Study sample. Reference group was defined in Framingham as those with: age (<50 years), blood pressure (BP, 140/90 mmHg), total cholesterol (<200 mg/dL), body mass index (<30 kg/m2), no diabetes, not currently smoking, and no history of CVD. Abnormal hemodynamic factors were defined as measurements outside the 95th or 5th percentile of the reference group. Using comparison of proportions, we determined the difference in abnormal prevalence rates between middle-aged AA in the Jackson Heart Study and non-Hispanic whites in Framingham. Results: The prevalence rates of abnormal hemodynamic variables in a middle-aged group of AA was compared to that seen in middle-aged non-Hispanic whites in Framingham using a published reference sample of normals in Framingham. Compared to non-Hispanic whites in Framingham, the prevalence of abnormals found in Jackson Heart Study AA was higher for diastolic BP (p=0.009), peripheral resistance (p<0.001), characteristic impedance (p=0.006), carotid-brachial pulse wave velocity (p=0.038) and cardiac output (p<0.001). Conclusion: Abnormalities in pulsatile hemodynamic variables are much more common (and severe) in AA than European Americans, which may contribute to higher CVD risk in AA.