DIFFERENCES IN THE EFFECT OF CIGARETTE-SMOKING ON ENDOTHELIAL FUNCTION IN CHINESE AND WHITE ADULTS

Background: The prevalence of coronary artery disease in southern Chin a is approximately one fifth that in ''westernized'' countries, even t hough approximately 70% of Chinese men smoke cigarettes and Chinese wo men have substantial passive exposure to cigarette smoke. Objectives: Endothelial dysfunction is an early event in atherosclerosis and occur s in young white active and passive smokers; we compared endothelial p hysiology in healthy young Chinese and white smokers and nonsmokers. P atients: 144 healthy adults who were 16 to 45 years of age: 72 Chinese persons in a village in southern China and 72 white persons in Austra lia and England who were matched for exposure to cigarette smoke. Each ethnic group comprised 36 controls (lifelong nonsmokers with no regul ar exposure to cigarette smoke; 16 men and 20 women) and 36 active or passive smokers (15 men and 21 women). Measurements: Arterial endothel ial function was tested with high-resolution external vascular ultraso nography, and brachial artery diameter was measured at rest, after flo w increase (which causes endothelium-dependent dilatation), and after administration of sublingual nitroglycerin (an endothelium-independent dilator). Results: Endothelium-dependent dilatation was similar in Ch inese (7.9%) and white (8.4%) nonsmokers (P > 0.2). Among white person s, endothelium-dependent dilatation was lower in active or passive smo kers (3.9%) than in nonsmokers (8.4%) (P < 0.001). Among Chinese perso ns, dilatation was not significantly lower in active or passive smoker s (7.3%) than in nonsmokers (7.9%) (P > 0.2). Dilatation was higher in Chinese active or passive smokers (7.3%) than in white active or pass ive smokers (3.9%) (P < 0.001). Dilatation responses to nitroglycerin were similar in all groups (P = 0.17). Conclusion: Young Chinese adult s have less evidence of arterial endothelial dysfunction than young wh ite adults with similar direct or indirect exposure to cigarette smoke .