Does low-density lipoprotein size add to atherogenic particle number in predicting the risk of fatal myocardial infarction?

The lipoprotein-related risk of coronary artery disease is determined principally by the balance between atherogenic lipoprotein particles, i.e., the lipoprotein that contain apolipoprotein-B (apo-B), and the antiatherogenic particles, i.e., high-density lipoprotein particles that contain apo-A-I. However, there is also considerable evidence that patients with predominantly small dense low-density lipoprotein (LDL) have more adverse clinical outcomes than do those with large buoyant LDL. The AMORIS study prospectively examined the relative importance of lipoprotein lipids versus apolipoproteins on the risk of fatal myocardial infarction in a large Swedish cohort. This updated analysis includes 69,029 men and 57,167 women who were followed for a mean of 10.3 years. Our objective was to determine whether LDL size as reflected by the LDL cholesterol/apo-B ratio added significant predictive power to apo-B or the apo-B/apo-A-I ratio. Although apo-A-I added significantly to the predictive power of apo-B, categorical and continuous multivariate analyses showed that this is not the case for LDL size. The strongest single lipoprotein-related risk factor was the apo-B/apo-A-I ratio. In conclusion, these results provide further confirmation of the importance of determining apo-B and apo-A-I in routine clinical practice. (c) 2006 Elsevier Inc. All rights reserved.