Epidemiology of insulin resistance and its relation to coronary artery disease.

The relation of insulin resistance to cardiovascular risk, particularly for coronary artery disease (CAD), has been well established in many prospective studies. The clustering of insulin resistance and/or hyperinsulinemia, hypertriglyceridemia, hypertension, and low HDL is now considered a feature of the insulin resistance syndrome. However, the association is complex and the pathways by which elevated insulin adversely affects both CAD risk factors and the risk of developing CAD have yet to be elucidated. Postprandial lipemia may be a mechanistic link between insulin resistance and CAD. Hyperinsulinemia appears to be a weak, but positive, independent cardiovascular risk factor. The strongest relations are seen in middle-aged rather than older persons and at higher elevations of plasma insulin levels. Individuals with type 2 diabetes have a risk of myocardial infarction (MI) equivalent to that of nondiabetic persons who have had a previous MI. Given the relatively weak association between duration of diabetes and severity of hyperglycemia and cardiovascular disease, common antecedents may underlie both CAD and type 2 diabetes.