Assessment of LDL Particle Size by Triglyceride/HDL-Cholesterol Ratio in Non-diabetic, Healthy Subjects without Prominent Hyperlipidemia

Small, dense low-density lipoprotein (LDL) is an atherogenic lipoprotein because of its susceptibility to oxidative modification. However, evaluating LDL size requires highly sophisticated techniques. We investigated potentially convenient biochemical parameters for assessing the presence of small, dense LDL. Thirty-nine male subjects, who had been involved in a work-site health promotion program, were recruited. Subjects were divided into two groups: normal LDL size (> 25.5 nm, Normal LDL group) and small LDL (≤ 25.5 nm, Small LDL group). Significant negative correlations were observed between LDL size and both triglyceride (TG) (p < 0.001) and remnant-like particle cholesterol concentrations (p < 0.01), while there was a significant positive correlation between LDL size and the high density lipoprotein cholesterol (HDL-C) concentration (p < 0.01). The TG concentration was a negative and the HDL-C concentration a positive independent variable predicting LDL size in multiple regression analysis (p < 0.0001). Seventy-five percent of the Small LDL group had TG/HDL-C ratios higher than 0.9 using mmol/L or 2.0 using mg/dL, while only 25% of the normal LDL group had ratios above the levels (p = 0.0013). A combined parameter, the TG/HDL-C ratio, is beneficial for assessing the presence of small LDL.