A comparison of endothelial function in Caucasian and Chinese women before and after the menopause

Abstract

Objective: Arterial endothelial dysfunction is a key atherogenic event that may be related to oestrogen status. We therefore aimed to compare menopause-related changes in endothelial physiology in Chinese and Caucasian females. Methods: We studied 40 female subjects; 20 Chinese from a rural region of Southern China (ten premenopausal, aged 20–35 years, and ten postmenopausal, aged 55–66 years), and 20 age-matched Caucasian females from Sydney, Australia. All women had a clinical history, resting blood pressure and fasting lipids measured, and endothelial function assessed. Using high-resolution external vascular ultrasound, brachial artery diameter was measured at rest, after flow increase (causing endothelium-dependent dilatation) and after sublingual glyceryl trinitrate (GTW) (an endothelium-independent dilator). Results: There was a significant decline in endothelium-dependent dilatation (EDD) comparing Caucasian females from the premenopausal versus postmenopausal groups (8.4±2.7% versus 2.7±2.9%; P<0.001). In contrast, there was no significant difference in EDD between pre- and postmenopausal Chinese (9.8±3.3% versus 8.3±1.7%; P=0.22). On multivariate analysis, postmenopausal status was associated with impaired EDD in Caucasian females ( P<0.002) independent of serum cholesterol, blood pressure and vessel size. In contrast, EDD in the Chinese females was not significantly influenced by any of these factors. GTW-induced dilatation was also impaired in the older Caucasian females, a finding explained on multivariate analysis by the increased vessel size in this patient group ( P=0.03). Conclusion: Menopause is associated with impaired arterial endothelial function in Caucasian but not Chinese women. This suggests possible ethnic differences in menopause-related vascular changes.