1. Division of Endocrinology, Metabolism, and Diabetes, University of Colorado , Aurora, CO 80045 , USA
2. Division of Endocrinology, Rocky Mountain Regional VA Medical Center , Aurora, CO 80045 , USA
3. Research Service, Rocky Mountain Regional VA Medical Center , Aurora, CO 80045 , USA
4. Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado , Aurora, CO 80045 , USA