Estimated Small Dense Low-Density Lipoprotein Cholesterol Is Independently Associated With Arterial Stiffness ― Large Japanese Screening Study ―

Background: Small dense low-density lipoprotein cholesterol (sdLDL-C) is an established atherogenic marker; however, the association between estimated sdLDL-C (EsdLDL-C) and arterial stiffness remains unclear. Methods and Results: We analyzed 23,623 participants (13,518 men, 10,105 women). EsdLDL-C was calculated using the Sampson equation, and arterial stiffness was defined as a brachial–ankle pulse wave velocity (baPWV) ≥1,400 cm/s. After adjustment for cardiovascular risk factors, higher EsdLDL-C levels were significantly associated with arterial stiffness in the overall population and in men, whereas the association in women did not reach statistical significance in the continuous analysis. Nevertheless, the risk of arterial stiffness increased in a stepwise manner across EsdLDL-C quartiles; the highest EsdLDL-C quartile had a significantly higher risk than the lowest in both men (odds ratio [OR] 1.91; 95% confidence interval [CI] 1.59–2.29) and women (OR 1.54; 95% CI 1.22–1.95). In a 4-group analysis, high EsdLDL-C significantly increased risk, regardless of whether estimated low-density lipoprotein cholesterol levels were below or above the median. Stratified analysis by systolic blood pressure (SBP; <120, 120–129, 130–139, and ≥140 mmHg) revealed that the association was significant across all categories in men, but was less consistent in women and was significant only in the strict normotensive group (SBP <120 mmHg). Conclusions: EsdLDL-C calculated from standard lipid parameters is significantly associated with arterial stiffness. This association is robust in men and evident in normotensive women, suggesting that EsdLDL-C is a useful indicator for arteriosclerotic risk assessment.