The Diabetes Prevention Program is a nationwide clinical study to answer the question: Can Type 2 diabetes (also called noninsulin-dependent or adult-onset diabetes) be prevented or delayed? The study has recruited 3819 volunteers, who are at high risk of developing diabetes, at twenty-five medical centers in the United States. It is sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, and other Institute and corporate sponsors. Researchers will evaluate the efficacy of a lifestyle intervention and a pharmacological intervention in preventing or delaying Type 2 diabetes in persons with IGT, impaired glucose tolerance. Each person in the study will be followed for 3 to 6 years.