Association of extremely high levels of high-density lipoprotein cholesterol with endothelial dysfunction in men.

It is not clear whether a high level of high-density lipoprotein cholesterol (HDL-C) is associated with lower risk of atherosclerosis. It is likely that HDL-C is a double-edged sword for atherosclerosis. The purpose of this study was to evaluate the relationship between HDL-C levels and endothelial function in men. This was a cross-sectional study. We evaluated flow-mediated vasodilation (FMD) and serum levels of HDL-C in 5842 men aged 18 to 92 years who were not receiving lipid-lowering therapy. All participants were divided into four groups by HDL-C level: low HDL-C (<40 mg/dL), moderate HDL-C (40–59 mg/dL), high HDL-C (60–79 md/dL), and extremely high HDL-C (≥80 mg/dL). We were not able to evaluate the amount of alcohol intake because there was limited information on the amount of alcohol drinking in our database. FMD values were significantly smaller in the low group and the extremely high group than in the high group (P =.001 and P =.016, respectively). There was no significant difference in FMD between the low group and the extremely high group. Multiple logistic regression analysis revealed that extremely high HDL-C, but not low HDL-C, was independently associated with the lowest quartile of FMD (odds ratio: 1.39, 95% confidence interval: 1.09–1.77; P =.009). An extremely high level of HDL-C in men (8.1% of this population) was associated with a significant reduction in FMD. • Flow-mediated vasodilation (FMD) was smaller in the low high-density lipoprotein cholesterol (HDL-C) than in the high HDL-C group. • FMD was smaller in the extremely high HDL-C group than in the high HDL-C group. • There was no difference in FMD between the low and extremely high HDL-C groups. • Extremely high HDL-C was associated with a lower quartile of FMD. [ABSTRACT FROM AUTHOR]