Deleterious Impact of “High Normal” Glucose Levels and Other Metabolic Syndrome Components on Arterial Endothelial Function and Intima-Media Thickness in Apparently Healthy Chinese Subjects: The CATHAY Study

Abstract

Objective— Endothelial vasodilator dysfunction and carotid intima-media thickening are useful surrogate markers of cardiovascular disease, a major cause of morbidity and mortality in type 2 diabetic patients. However, because most studies reporting the relationships between endothelial function, intima-media thickness (IMT), and hyperglycemia have compared diabetic patients with healthy controls, we report their relationship with glycemia as a continuum. Methods and Results— Brachial artery endothelial function (flow-mediated dilatation [FMD]) and carotid IMT were measured noninvasively by high-resolution ultrasound B-mode imaging in 228 apparently healthy Chinese subjects recruited from Hong Kong and Macau. FMD and IMT were significantly associated with increasing levels of glycemia, particularly in the “high normal” glycemic range, with IMT increasing and endothelium-independent dilatation decreasing linearly across the glucose tertiles, and endothelium-dependent dilatation significantly lower in the upper glucose tertile compared with the other 2 groups ( P <0.01). Using multiple linear regression, fasting glucose level was identified as an independent predictor of each of these markers of vascular function ( P <0.004). Additionally, other conventional cardiovascular risk factors, including obesity, blood pressure, and an adverse lipid profile, were also related to levels of glycemia ( P <0.05), further contributing to impaired vascular function. Conclusion— Increasing levels of glycemia and the coexistence of other cardiovascular risk factors in apparently healthy subjects are adversely associated with arterial endothelial dysfunction and intima-media thickening.