The Diabetes Prevention Program, sponsored by NIDDK, is a multicenter controlled clinical trial examining the efficacy of an intensive life-style intervention or metformin to prevent or delay the development of diabetes in a population selected to be at high risk due to the presence of impaired glucose tolerance (IGT). The DPP began recruitment in mid-1996 and 3,234 volunteers were enrolled in the 3-arm study. On the basis of a statistically significant and clinically compelling decrease in the development of diabetes in the life-style intervention and metformin-treated groups (58% and 31% reductions, respectively) compared with the placebo treated group, the DPP Data Monitoring Board and NIDDK ended the masked treatment phase of the study in May, 2001, one year earlier than originally planned. This cohort will continue to be followed in a subsequent study, which will consist of an epidemiologic type of study with everyone receiving life-style intervention. The specific aims of the follow-up studies include: 1. Examine the long-term effects and durability of prior DPP intervention on the major DPP outcomes including diabetes, clinical cardiovascular disease, atherosclerosis, CVD risk factors, quality of life and cost-benefit; 2. Determine the clinical course of new onset type 2 diabetes and IGT, in particular regarding microvascular and neurologic complications; 3. Determine the incidence of cardiovascular disease (CVD), CVD risk factors and atherosclerosis in new onset type 2 diabetes and IGT; and 4. Examine topics 1-3 in minority populations, men vs. women, and in older subjects in the DPP. An eye component has been added to the follow-up study. This consist of baseline eye exam and fundus photography of patients who develop diabetes and a sample of the cohort that have not developed diabetes. The eye exams and photographs may be repeated at years 4 and 9 of the study. We will evaluate rates of development of the ocular complications of those with newly diagnosed diabetes and those with impaired oral glucose tolerance tests. We will also evaluate the glycemic level at which the ocular complications may develop.