1. Department of Cardiology, Duke University Health System, Durham, NC
2. Department of Biostatistics and Bioinformatics, Duke University, Durham NC
3. Department of Medicine, Duke University, Durham NC
4. Duke Clinical Research Institute, Durham, NC
5. Division of Physical Therapy, Department of Orthopedic Surgery, Duke University, Durham, NC
6. Claude D. Pepper Older Americans Independence Center, Duke University School of Medicine, Durham, NC