Insulin resistance and atherosclerosis. Common roots for two common diseases?

Abstract

Growing up in postwar Germany as I did taught me something that is hard to forget. When people had relatively little to eat, diseases such as NIDDM and atherosclerosis were almost unheard of. Today, these diseases occur in epidemic proportions. Furthermore, atherosclerosis is now the most common and deleterious complication of NIDDM. This issue of Circulation contains the first, long-awaited results of the Insulin Resistance Atherosclerosis Study, which examines the association between insulin sensitivity and IMT of the carotid artery as an index of atherosclerosis. The study is based on observations in three distinctly different ethnic groups of approximately equal size in four communities of the United States.1 The results show an inverse relation between insulin sensitivity and atherosclerosis in Hispanic and non-Hispanic white Americans but not among black Americans. When the investigators adjusted their results for the traditional risk factors of coronary artery disease, glucose tolerance, measures of adiposity, and fasting insulin levels, this inverse relation was reduced but not eliminated. The powerful analysis suggests therefore that insulin resistance per se is an independent cause of atherosclerosis in non-Hispanic and Hispanic whites. It also suggests that the inverse relation between insulin sensitivity and atherosclerosis is stronger than the relation between insulin and atherosclerosis. The ethnic differences are not so readily explained, although it is of interest that non-Hispanic and Hispanic whites share the same characteristics. The findings of the present study1 provide support for the clinical observation that diabetes and macrovascular disease not only coexist but may spring from common roots. On the one hand, the results suggest that it is possible to identify patients early who are at risk for the development of atherosclerotic vascular disease. On the other hand, they provide a challenge for the practicing physician to diagnose and treat subclinical forms of glucose …