1. From the Division of Clinical Epidemiology (B.D.M., R.V., M.P.S.), Department of Medicine, University of Texas Health Science Center, San Antonio, the Centro de Estudios en Diabetes (C.G.V., B.A.P., M.S.G.), The American British Cowdray Hospital, Mexico City, and the Servicio de Endocrinología (C.G.V.), División de Medicina, Hospital de Especialidades, “Dr. Bernardo Sepúlveda,” Centro Médico Nacional, Instituto Mexicano del Seguro Social, Mexico City, Mexico.