Persistence of Low HDL-C Levels After Weight Reduction in Older Men With Small LDL Particles

LDL subclass pattern B is characterized by a predominance of small LDL particles (LDL peak particle size ≤255 Å) and is associated with increased plasma triglyceride (TG) and reduced HDL cholesterol (HDL-C) concentrations. This study compared the effect of weight loss on lipoprotein and glucose metabolism in 15 healthy, obese (body mass index [BMI], 30.9±2.4 kg/m 2 ), older (60±9 years) men with LDL pattern B and in 25 men of comparable age and BMI with LDL pattern A (LDL peak particle size ≥260 Å). At baseline, men with LDL pattern B had higher TG and lower apolipoprotein (apo) A-I, HDL-C, and HDL 2 -C levels ( P <.001) than men with LDL pattern A, while the total cholesterol and LDL cholesterol levels and fasting and 2-hour postprandial glucose and insulin levels did not differ between groups. With weight loss (10.1±3.6 kg) there were significant decreases in 2-hour postprandial glucose and insulin levels in men with LDL patterns B and A ( P <.05). However, the change in plasma TG, HDL-C, HDL 2 -C, and apoA-I levels with weight loss differed between groups. In men with LDL pattern A, plasma TG levels decreased by 15% ( P <.001) compared with a 34% ( P <.001) decrease in LDL pattern B (two-factor ANOVA, P <.01). Plasma HDL-C concentrations increased by 0.16 mmol/L ( P <.001) in the men with LDL pattern A but by only 0.07 mmol/L in the men with LDL pattern B (two-factor ANOVA, P <.05). After weight loss, only 5 of the 15 men with LDL pattern B had HDL-C levels above 0.90 mmol/L (35 mg/dL), whereas 22 of 25 men with LDL pattern A had HDL-C levels above 0.90 mmol/L (χ 2 =18, P <.0001). Furthermore, with weight loss, 11 of the 15 men with LDL pattern B increased their LDL peak particle diameter; 7 converted to intermediate LDL pattern, and 4 converted to LDL pattern A. By comparison, there were no significant changes in weight, lipoprotein, or apolipoprotein concentrations at 1-year follow-up in 12 metabolic control subjects. Thus, despite significant reductions in weight and body fat and concomitant decreases in plasma TG and insulin levels, HDL-C and HDL 2 subspecies levels remain low in men with LDL pattern B.