Association of Cumulative Low-density Lipoprotein Cholesterol Exposure with Vascular Function

BACKGROUND : The relationship between cumulative low-density lipoprotein cholesterol (LDL-C) exposure and progression of atherosclerosis remains uncertain. OBJECTIVE : The aim of this study was to determine the relationship between cumulative LDL-C level and flow-mediated vasodilation (FMD), nitroglycerine-induced vasodilation (NID) and the presence of plaque in the common carotid artery (CCA). METHODS : This was a cross-sectional study. We measured FMD in 8208 subjects, NID in 1822 subjects, and CCA plaque in 591 subjects who were not taking lipid-lowering drugs. The subjects were divided into four groups based on cumulative LDL-C exposure: <4000 mgཥyear/dL, 4000-4999 mgཥyear/dL, 5000-5999 mgཥyear/dL, and ≥6000 mgཥyear/dL. RESULTS The odds ratio of the lower quartile of FMD in the cholesterol-year-score <4000 mgཥyear/dL group was significantly higher than the odds ratios in the other groups. The odds ratio of the lower quartile of NID in the <4000 mg・year/dL group was significantly higher than the odds ratios in the 5000-5999 mgཥyear/dL and ≥6000 mgཥyear/dL groups. The odds ratio of the prevalence of CCA plaque in the <4000 mg・year/dL group was significantly higher than that in the ≥6000 mgཥyear/dL group. CONCLUSIONS : Endothelial dysfunction occurred from cumulative LDL-C exposure of 4000 mg・year/dL, vascular smooth muscle dysfunction occurred from cumulative LDL-C exposure of 5000 mgཥyear/dL, and prevalence of CCA plaque occurred from cumulative LDL-C exposure of 6000 mgཥyear/dL. Clinical Trial Registry Information http://www.umin.ac.jp (UMIN000012950, UMIN000012951, and UMIN000012952, UMIN000003409)