The study was extended to follow the cohort for an additional three years to achieve the following specific aims: 1. To determine, among type 1 diabetic (T1D) patients and comparable controls, the risk factors for: a. 6-year progression of electron-beam tomography (EBT) defined coronary calcification - marker of coronary atherosclerosis b. 6-year development of myocardial perfusion defects and changes in relative myocardial perfusion reserve defined using ECG-gated rest-stress technetium-99m MIBI SPECT imaging c. 6-year incidence of clinical CAD, defined by fatal and non-fatal MI, revascularization or angina, as well as stroke, peripheral artery disease and cause-specific mortality. 2. To develop a clinically useful measure of insulin sensitivity that is directly comparable between T1D patients and non-diabetic persons to more precisely determine the role of insulin resistance in development of premature CAC in type I diabetes.