Association of Elevated Non-HDL-C and LDL-C with Carotid atherosclerosis among Tibetans Living at High Altitudes: A Cross-sectional Study

Background: Hypoxic circumstances impair endothelial function and may contribute to carotid atherosclerosis. In high-altitude areas, there is a scarcity of data on the correlation between lipid particles and carotid atherosclerosis. Methods: A total of 587 patients who underwent carotid artery ultrasound and met the inclusion and exclusion criteria were enrolled in our cross-sectional study. All participants resided in Luhuo County, Ganzi Tibetan Autonomous Prefecture, Sichuan Province, China (mean altitude: 3,860 meters). We used questionnaires, physical examination, blood sample testing, and ultrasound in our investigation. Spearman correlation analysis and multiple linear regression analysis were performed to explore the association between lipid particles and carotid atherosclerosis. We compared the disparity between lipid particles in predicting atherosclerosis using the receiver operator characteristic curve. Results: We found a statistically significant association between lipid particles and carotid atherosclerosis. After adjustment for certain variables, including age, gender, mean arterial pressure, and fasting blood glucose, we discovered that non-high-density lipoprotein-cholesterol (non-HDL-C) was a risk factor for carotid intima-media thickness (β = 0.012, p = 0.032) but not for low-density lipoprotein cholesterol (LDL-C) (p = 0.073). In terms of lifestyle, non-HDL-C was also found to be a risk factor for atherosclerosis independent of cigarette smoking and vegetarian (β = 0.012, p = 0.049). The area under the curve (AUC) of non-HDL-C was 0.644 (CI: 0.583 – 0.706) while LDL-C was 0.599 (CI: 0.534 - 0.664) in predicting carotid atherosclerosis. The optimal cut-off value of non-HDL-C was 3.625 mmol/L in predicting carotid plaques. Conclusions: Among Tibetans living in high-altitude areas, non-HDL-C is a better biomarker than LDL-C for carotid artery atherosclerosis independent of conventional risk factors. It is crucial to resolve non-HDL-C dyslipidemia in order to mitigate carotid atherosclerosis in Tibetans living at high-altitude settings.