The associations of high-density lipoprotein subclasses with insulin and glucose levels, physical activity, resting heart rate, and regional adiposity in men with coronary artery disease: The stanford coronary risk intervention project baseline survey

Abstract

We used nondenaturing polyacrylamide gradient gel electrophoresis to examine the associations of high-density lipoprotein (HDL) subclasses with adiposity, physical activity, resting heart rate (an indicator of sympathetic drive), and plasma insulin and glucose levels in 97 men with angiographically documented coronary artery disease. These men neither smoked nor used medications known to affect lipoproteins. The absorbency of protein stain was used as an index of mass concentrations at intervals of 0.01 nm within five HDL subclasses: HDL 3c (7.2 to 7.8 nm), HDL 3b (7.8 to 8.2 nm), HDL 3a (8.2 to 8.8 nm), HDL 2a (8.8 to 9.7 nm), and HDL 2b (9.7 to 12 nm). HDL peak diameter was determined from the predominant peak of the HDL particle distribution when plotted against particle diameter. Four men who were non—insulin-dependent diabetics as defined by a fasting glucose exceeding 140 mg/dL had significantly higher plasma HDL 3b levels and significantly smaller HDL peak diameters than nondiabetic men, and were therefore excluded from further analyses. In the remaining 93 nondiabetic men, plasma HDL 3b levels correlated positively with indices of truncal obesity (waist to hip ratio and subscapular skinfold), whereas plasma HDL 2b levels correlated negatively with indices of total adiposity (body mass index [BMI]) and truncal obesity (subscapular and abdominal skinfold). Fasting plasma insulin levels correlated negatively with HDL 3a, HDL 2a, and HDL 2b. Obesity significantly affected the relationships of resting heart rate with insulin and HDL subclasses. In heavier men (BMI > 25.8 kg/m 2) but not in the less-obese men (BMI < 25.8 kg/m 2), resting heart rate was negatively correlated with HDL 3a, HDL 2a, and HDL 2b levels and HDL peak diameter and positively correlated with fasting plasma insulin concentrations. Although the reported physical activity in heavier men also correlated with HDL 3a, HDL 2a, and resting heart rate, the associations of resting heart rate with HDL 3a, HDL 2a, and HDL 2bcould not be attributed to activity level. These analyses suggest that the influences of plasma insulin, regional adiposity, physical activity, and resting heart rate on HDL involve specific HDL subclasses. In the presence of increased adiposity, sympathetic drive and physical inactivity may reduce levels of larger HDL and the peak diameter of the major HDL subspecies.