We evaluated whether black race is independently associated with arterial endothelial dysfunction. The pathophysiological basis for race-related differences in cardiovascular disease (CVD) risk has not been established. Endothelial dysfunction, which precedes obstructive atherosclerotic disease, may contribute to CVD disparities. Accordingly, we evaluated race-related differences in digital pulse amplitude tonometry (PAT) response to an endothelium-dependent vasodilatory stimulus. A total of 1377 subjects (41% black; mean age 58.5 ± 7.5 years; 67% female) enrolled in the Heart Strategies Concentrating on Risk Evaluation (Heart SCORE) study underwent assessment of digital pulse amplitude response to forearm occlusion-induced hyperaemia. The response was measured as a PAT ratio of hyperaemia:baseline pulse amplitude in a finger that was subject to hyperaemic stimulus divided by this same ratio in a control finger on the contralateral arm which did not undergo forearm occlusion, expressed as the natural logarithm. The average PAT ratio was significantly lower in blacks compared with whites (0.67 ± 0.44 vs. 0.80 ± 0.46, P < 0.001), signifying greater endothelial dysfunction in blacks. Black race was independently correlated with lower PAT ratio. This finding was consistent across all Framingham risk strata. Adjusted analyses showed significant gender-race interactions. With white women serving as the referent group, parameter estimates for lower PAT ratio in ascending order were as follows: black males (t = -6.93, P < 0.0001); white males (t = -3.31, P = 0.001); and black females (t = -1.12, P = 0.26). Our findings indicate that black race is independently associated with arterial endothelial dysfunction. Racial differences in CVD risk may be related, in part, to race-related differences in endothelial dysfunction.
