1. Tufts University School of Medicine, Boston, Massachusetts
2. Department of Family Medicine, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts
3. School of Physical Therapy, Massachusetts College of Pharmacy and Health Sciences, Worcester, Massachusetts
4. Massachusetts Veterans Epidemiology, Research and Information Center (MAVERIC), US Department of Veterans Affairs, VA Boston Healthcare System, Boston, Massachusetts
5. Division of General Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
6. Kaiser Permanente Washington Health Research Institute, Seattle, Washington
7. Department of Epidemiology, University of Washington, Seattle, Washington
8. Department of Rehabilitation Science, MGH Institute of Health Professions, Boston, Massachusetts, USA