Editorial Comment

In this issue of Circulation, Koenig and colleagues' report associations between plasma viscosity, se-rum cholesterol, and certain lipoproteins in a population study in Augsburg, Germany. Recently, Cir-culation also published a report by Yarnell et a12 from the Caerphilly and Speedwell Collaborative Studies in England and Wales indicating that plasma viscosity was an important predictor of ischemic heart disease in middle-aged men. It is therefore appropriate to review recent epidemiological studies of plasma and whole-blood viscosity and their relations to lipids, lipoproteins, other cardiovascular risk markers, and cardiovascular disease. See p 2197 Plasma viscosity is the intrinsic flow resistance o