Abstract
Lipoprotein subfractions and particle sizes are increasingly used in observational studies to predict the risk of cardiovascular diseases. However, the causal role of the different subfractions remain largely uncertain because the conventional study designs are subject to unmeasured confounding. We used Mendelian randomization and public GWAS summary data to estimate the effect of 82 lipoprotein subfraction and particle size traits on the occurrence of coronary artery disease and myocardial infarction. We found that, unlike LDL and VLDL subfractions, HDL subfraction traits appear to have heterogeneous effects on coronary artery disease according to particle size. The concentration of medium HDL particles may have a protective effect on coronary artery disease that is independent of traditional lipid factors.