Racial differences of endothelial function and plasma endothelin 1 level in preclinical Tibetan and Han male population

OBJECTIVE: The differences in endothelial function between Tibetan and Han nationality population have not been fully investigated. The aim of this work is to investigate the differences in endothelial function and plasma endothelin 1 (ET-1) concentration between Tibetan and Han male population. PATIENTS AND METHODS: Totally 272 Tibetan male subjects aged 42.9 +/- 9.4 years were enrolled in this study to stand for Tibetan population. All of them were native residents in Lhasa City. And 580 Qinghai-Tibet Railway constructors with Han nationality aged 41.8 +/- 11.1 years were enrolled in this study to stand for Han nationality population. All of them were male subjects and lived in Lhasa City for at least 1 year. All subjects lived in the same high-altitude area (the altitude of Lhasa is 3658 m). Height, weight, waist circumference, hip circumference, systolic blood pressure, diastolic blood pressure were evaluated. Body mass index (BMI) was calculated. Brachial artery flow-mediated dilation (FMD) was measured in the fasting state using high-resolution B-mode ultrasound. Computer-assisted analysis software was used to calculate brachial artery diameters. Venous blood was sampled for the measurement of total cholesterol (CH), triglyceride (TG), high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL) and HbA1c. Plasma ET-1 was quantitated using a commercially available ELISA kits. RESULTS: Totally 272 Tibetan subjects and 580 Han nationality subjects were enrolled in this study. BMI and waist-hip ratio in Tibetan subjects were much higher than those in Han subjects (p < 0.01). LDL cholesterol level and plasma ET-1 concentration in Tibetan subjects were significantly higher than Han subjects (p < 0.01). The baseline brachial artery diameter in Tibetan group was much higher than that of Han group (p < 0.01). The absolute and percent changes in brachial artery diameter were lower in Tibetan population compared with Han population (p < 0.01). The linear regression analysis showed that LDL cholesterol, and plasma ET-1 were correlated with FMD (p < 0.01). CONCLUSIONS: Endothelial function and plasma ET-1 concentration were different between Tibetan and Han male populations.