Impact of mean arterial blood pressure on higher arterial stiffness indices in South Asians compared to white Europeans.

Background: The pathophysiology of excessive premature coronary heart disease mortality among South Asians living in Britain remains unclear. We hypothesized that higher measures of arterial stiffness among South Asians compared with their white European counterparts would reflect an earlier progression of atherosclerosis, even in the absence of established coronary heart disease risk indices.

Methods: Arterial stiffness was measured by digital volume pulse photoplethysmography in 90 healthy South Asians and compared with 62 matched white Europeans in a temperature-controlled environment using a direct, standardized approach.

Results: Both ethnic groups were comparable for coronary heart disease risk profiles and had similar 10-year coronary heart disease risk estimates, but South Asians had a greater mean (SD) stiffness index compared with white Europeans [9.39 (0.22) vs. 8.43 (0.23) m/s; P = 0.007]. On linear regression analysis, mean arterial blood pressure (beta = 0.06; P = 0.03) and age (beta = 0.11; P = 0.002) were independent predictors of arterial stiffness in South Asians. Among white Europeans, age was an independent predictor of arterial stiffness (beta = 0.05; P = 0.01).

Conclusion: Healthy South Asians have increased systemic arterial stiffness measured by stiffness index compared with white Europeans. There was an adverse and disproportional impact of age and mean arterial pressure on the vascular system in South Asians. Increased indices of arterial stiffness may explain their increased susceptibility to coronary heart disease.