The purpose of the ICARUS (Insulin-Carotids US-Scandanavia) Study is to compare the effects of Losartan versus Atenolol, two drugs that are marketed for the treatment of high blood pressure being used in the LIFE (Losartan Intervention For Endpoint Reduction in Hypertension) Study, on carotid artery wall thickness, insulin sensitivity, and forearm blood flow. The carotid artery is a blood vessel in the neck carrying blood to the brain. Insulin sensitivity is a measure of the way the body metabolizes sugar.