1. Department of Endocrinology, Duke University Medical Center, Durham, North Carolina;
2. Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina;
3. Department of Exercise and Sports Science and Human Performance Laboratory, East Carolina University, Greenville, North Carolina; and
4. Physical Medicine and Rehabilitation, Veterans Affairs Medical Center, Durham, North Carolina
5. Division of Geriatrics, Duke University Medical Center, Durham, North Carolina;
6. Duke Center for Living, Duke University Medical Center, Durham, North Carolina;