1. Donald W. Reynolds Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
2. Veterans Affairs Medical Center, Oklahoma City, OK, USA
3. Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
4. General Internal Medicine Section, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
5. CMRI Diabetes and Metabolic Research Program, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
6. Cardiovascular Section, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA