The Diabetes Control and Complications Trial (DCCT) was a landmark study conducted from 1983 to 1993 designed to explore whether intensive glucose control could delay or possibly even prevent diabetes-related complications. In this study, intensive control meant keeping hemoglobin A1C levels at 6% or less. Until the DCCT, numerous studies pointed toward confirming the hypothesis that lower glucose levels reduced the risk of complications. But no long-term studies had conclusively proven this.
The study involved 1,141 volunteers, ages 13 to 39, with type 1 diabetes and was conducted at 29 medical centers throughout North America. The results of the 10-year study showed that maintaining blood glucose levels in a more or less normal range can slow the onset and progression of eye, kidney, and nerve damage caused by diabetes. It further stated that any lowering of blood sugar levels was beneficial even when the person with diabetes had a history of poor glucose control.
At the close of the DCCT a follow-up study was launched, called the Epidemiology of Diabetes Interventions and Complications (EDIC). Under the EDIC, the original DCCT cohort is being followed to assess how intensive blood glucose control affects the heart and small and large blood vessels throughout the body. This study is scheduled to continue until 2016.