OBJECTIVE— The Diabetes Control and Complications Trial (DCCT) demonstrated the powerful impact of glycemic control on the early manifestations of microvascular complications.

Contemporary prospective data on the evolution of macrovascular and late micro vascular complications of type 1 diabetes are limited. The Epidemiology of Diabetes Interventions and Complications (EDIC) study is a multicenter, longitudinal, observational study designed to use the well-characterized DCCT cohort of 1,400 patients to determine the long-term effects of prior separation of glycemic levels on micro- and macrovascular outcomes. EDIC is in its 13th year of followup. The study is expecting to last until 2016.

RESEARCH DESIGN AND METHODS— Using a standardized annual history and physical examination, 28 EDIC clinical centers that were DCCT clinics will follow the EDIC cohort for 10 years. Annual evaluation also includes resting electro c a rdiogram, Doppler ultrasound measurements of ankle/arm blood pressure, and screening for nephropathy. At regular intervals, a timed 4-h urine is collected, lipid pro files are obtained, and stereoscopic fundus photographs are taken. In addition, dual B-mode Doppler ultrasound scans of the common and internal carotid arteries will be perf o rmed at years 1 and 6 and at study end.