The University of Minnesota CF Center is in the unique position of having a well-characterized diabetes population, since diabetes screening was instituted several years ago as part of routine annual CF studies. In our population of 450 CF patients, 113 have been diagnosed with diabetes, and the remainder are known to have either normal or impaired glucose tolerance. In addition to our CFRD experience, the University of Minnesota has a strong background of experience in large population-based screening and intervention trials concerning diabetes complications. Not only were we a participating center in the NIH-sponsored multi-center Diabetes Control and Complications Trial (DCCT) (2) and the current DCCT follow-up Epidemiology of Diabetes Interventions and Complications trial (EDIC), but our laboratory was central reference laboratory for the DCCT and EDIC. Thus, our physicians, nurses, biostatisticians, GCRC staff and laboratory staff are all quite knowledgeable and experienced in the methods to be used in the present application.