THE TOTAL APOLIPOPROTEIN-B LDL-CHOLESTEROL RATIO DOES NOT PREDICT LDLPARTICLE-SIZE

Small dense low density lipoprotein (LDL Pattern B) particles are asso ciated with low plasma concentrations of high density lipoprotein (HDL )-cholesterol and high concentrations of triglyceride and also with oc currence of coronary heart disease, Because LDL size is not measured e asily, the ability of plasma total apolipoprotein (apo) B and a calcul ated LDL-apo B combined as a ratio with LDL-cholesterol (Friedewald) t o predict LDL Pattern B (peak LDL size < 25.5 nm) was examined in 100 plasma samples with triglyceride 0-5 mmol/l. LDL-apo B was calculated using the regression line comparing measured LDL-apo B/total apo B wit h triglyceride and was correlated strongly.(r = 0.94) with measured LD L-apo B. There was no difference in either ratio between plasma sample s with LDL Pattern A (peak LDL size greater than or equal to 25.5 nm) or Pattern B for samples with triglyceride > 2.0 mmol/l. An apo B/chol esterol ratio was measured for LDL separated by ultracentrifugation an d was higher in plasma with LDL Pattern B than Pattern A (P = 0.018). Nevertheless, in combination with LDL-cholesterol, neither total apo B nor a calculated LDL-apo B was useful in predicting LDL particle size .