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: HDL3c (7.2 to 7.8 nm), HDL3b (7.8 to 8.2 nm), HDL3a (8.2 to 8.8 nm), HDL2a (8.8 to 9.7 nm), and HDL2b (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 HDL3b levels and significantly smaller HDL peak diameters than nondiabetic men, and were therefore excluded from further analyses. In the remaining 93 nondiabetic men, plasma HDL3b levels correlated positively with indices of truncal obesity (waist to hip ratio and subscapular skinfold), whereas plasma HDL2b 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 HDL3a, HDL2a, and HDL2b. Obesity significantly affected the relationships of resting heart rate with insulin and HDL subclasses.(ABSTRACT TRUNCATED AT 250 WORDS)

Figures

Fig 1

Mean absorbency of protein-stained HDL by particle size in four untreated non-insulin-dependent diabetic men (fasting plasma glucose > 140 mg/dL) and 93 nondiabetic men (top)), and the mean differences between diabetic and nondiabetic men (bottom). The curves were computed by averaging the heights of the individual HDL distributions at each diameter value. The solid portions of the bar at the bottom of the graph designate those diameter values that achieve statistical significance for the differences (P≤ 0.05) for two sample t test. The predominant HDL peak diameters are indicated, and the subclass intervals defined by Blanche et al [1] are provided for reference. The untreated diabetics had significantly smaller HDL peak diameter (mean ± SD: 7.86 ± 0.06 vs. 8.21 ± 0.20 nm) than nondiabetic men and significantly higher HDL3b,

Fig 2

Pearson correlation coefficients between plasma insulin and glucose levels and the absorbency of protein-stained HDL by particle size, The solid portions of the bars at the bottom of the graphs designate the range of diameter values that correlate significantly at P ≤0.05. The subclass intervals defined by Blanche et al [1] are provided for reference.

Fig 3

Pearson correlation coefficents between adiposity and absorbency of protein-stained HDL by particle size. The solid portions of the bars at the bottom of the graphs designate the range of diameter values that correlate significantly at P ≤0.05. The subclass intervals defined by Blanche et al [1] are provided for reference.

Fig 4

Pearson correlation coefficients of resting heart rate (top) and reported physical activity (middle) with absorbency of protein stained HDL by particle size. Partial correlations between resting heart rate and protein-stained HDL adjusted for physical activity are shown in the bottom panel. Results are presented for all 93 men, Low-BMI men (BMI≤ 25.8 kg/m2, n = 47), and high-BMI men (BMI ≥ 25.8 kg/m2, n = 46). The solid portions of the bars at the bottom of the graphs designate the range of diameter values that correlate significantly at P ≤ 0.05. The subclass intervals defined by Blanche et al [1] are provided for reference.

Fig 5

Regression lines depicting the relationships of resting heart rate with the predominant HDL peak diameter (top) and fasting insulin levels (bottom). Separate lines are shown for the Low-BMI man (BMI ≤25.8 kg/m2, n = 47) and high-BMI men (BMI ≥ 25.8 kg/m2, n = 46). Significance levels refer to the difference in slopes between the low-and high-BMI men.

Fig 6

Partial correlational analyses between HDL protein levels and fasting plasma insulin, BMI, subscapular skinfold, resting heart rate, and reported physical activity. Expanded portions of the lines designate the range of diameter values that correlate significantly at P ≤0.05 when adjusted. *In heavier men only (25.8 kg/m2 ≤ BMI ≤ 36.3 kg/m2).