The prognosis and effect of treatment of impaired glucose tolerance (IGT) are studied in residents of Malm[unreadable]hus County, Sweden. Mortality rates are determined in over 2000 persons who had glucose tolerance tests in the 1960s, and results are related to glucose tolerance and other factors at baseline. Some of these subjects participated in a randomized treatment study of IGT. New studies in population screening and treatment of IGT are being planned.