he epidemic of obesity in the developed and develop- ing world has resulted in a considerable increase in the number of patients with high plasma triglyceride concentrations. There has been considerable debate about the role of triglyceride-rich lipoproteins (TRLs) in atherosclero- sis. These lipoproteins include chylomicrons, VLDL, IDL, and various remnant particles. Although elevated triglyceride levels are common in patients with atherosclerotic disease, establishing a clear link has been made difficult by a number of factors. See page 307 First, elevated triglycerides are usually found in lipoprotein particles that also contain cholesterol. A role for cholesterol in these particles is supported by the fact that non-HDL cholesterol appears to be a more powerful marker of cardiovascular risk than even LDL cholesterol.1 Second, elevated TRLs are strongly associated with low HDL cholesterol concentrations. This asso- ciation is so powerful that it is very difficult to dissect out the relative contributions of HDL and TRLs, although low HDL is