OBJECTIVE To test the hypothesis that abnormalities of endothelial function are present in Indian Asians and may contribute to their increased coronary heart disease risk.

SETTING Single centre in west London.

PATIENTS 26 Indian Asian and 18 European white healthy male subjects, aged 35 to 61 years recruited from general practice lists.

DESIGN Brachial artery diameter responses to reactive hyperaemia and sublingual glyceryl trinitrate were compared using high resolution ultrasound.

RESULTS Mean (SEM) flow mediated, endothelium dependent dilatation was reduced in Indian Asians compared with European whites, at 3.2 (0.8)%v 5.9 (1.0)%, p = 0.03. In contrast, there were no significant differences in baseline brachial arterial diameter (4.6 (0.1) v 4.6 (0.1) mm, p = 0.65) or glyceryl trinitrate induced dilatation (18.8 (1.5)%v 18.5 (1.7)%, p = 0.90) between Indian Asians and European whites, respectively. Univariate analysis showed that Indian Asian race was significantly associated with impaired flow mediated dilatation (regression coefficient = −2.8 (1.3)%, p = 0.03), and in multivariate analysis, this relation was independent of both conventional coronary heart disease risk factors and markers of insulin resistance.

CONCLUSIONS Endothelial function is impaired in healthy UK Indian Asians compared with European whites, and the defect is not accounted for by major coronary heart disease risk factors. Endothelial function may be modulated by novel risk factors in Indian Asians.