The relevance of a protein-enriched low density lipoprotein as a risk for coronary heart disease in relation to other known risk factors.

The significance of a decreased low density lipoprotein cholesterol/apolipoprotein B ratio (LDL-chol/LDL apo B), or protein-enriched LDL, to predict atherosclerosis was studied in 121 males with angiographically defined coronary artery disease (CAD) and compared to 98 male controls, without history or complaints of vascular disease. Controls were selected for similar age, smoking habits and relative body weight characteristics compared to the CAD group. Covariance analysis with adjustment for hyperlipoproteinemia, apoprotein E phenotype, smoking, age and relative body weight revealed that high density lipoprotein (HDL)-cholesterol was the only parameter that differed significantly between both groups. By logistic regression analysis HDL-cholesterol had the highest predictive power for the development of CAD. The LDL-chol/LDL apo B ratio appeared significantly different between controls and CAD patients (3.1 +/- 0.7 vs. 2.9 +/- 0.6 mmol/g, P less than 0.05), indicating a predominance of subjects with protein-enriched LDL in the CAD group. However, within the group of CAD patients with normal LDL-cholesterol levels no clear distinction could be found between patients with normal and increased LDL apo B levels. Furthermore, it appeared that the LDL-chol/LDL apo B ratio correlated significantly with age (p = -0.24), serum triglycerides (p = -0.24), and HDL-cholesterol (p = 0.24). Thus, the LDL-chol/LDL apo B ratio cannot be considered an independent risk factor for CAD. When adjusted for age, smoking habits and relative body weight the significance of protein-enriched LDL as a risk factor for coronary heart disease diminishes, and HDL-cholesterol appears to be the best indicator for CAD.