Racial differences in aortic stiffness in normotensive and hypertensive adults

OBJECTIVE: To investigate whether differences exist in the mechanical properties of large arteries between white and black subjects. DESIGN: Eighty-two white (49 normotensive and 33 untreated hypertensive) and 38 black (24 normotensive and 14 untreated hypertensive) adult male volunteers were studied in a cross-sectional study. METHODS: Carotid-femoral pulse wave velocity was measured as an index of arterial stiffness, using a recently developed non-invasive automatic device, and compared between white and black subjects before and after the adjustment for age. The slope of regressions for pulse wave velocity and systolic blood pressure were also compared between racial groups. RESULTS: In the normotensive group, white subjects presented higher mean values of pulse wave velocity than blacks while the opposite behavior was found in the hypertensive group. After adjustment for age, significant differences in pulse wave velocity between whites and blacks became evident in the normotensive (whites 8.15 +/- 0.04 versus blacks 7.75 +/- 0.02 m/s; P < 0.001) and hypertensive (whites 8.88 +/- 0.02 versus blacks 9.30 +/- 0.17 m/s; P < 0.001) groups. Linear regression analysis for age-adjusted pulse wave velocity and systolic blood pressure showed that the slope was significantly greater in blacks than in whites (0.040 +/- 0.002 versus 0.019 +/- 0.001 m/s; P < 0.001). CONCLUSION: These data indicate that there is a greater pressure-dependent increase in aortic stiffness in blacks than in whites. This finding points towards major differences in mechanical properties of large arteries between these racial groups.