1. Department of Medicine, Division of General Internal Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA;
2. Baylor College of Medicine, Houston, TX, USA;
3. National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ, USA;
4. Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA;
5. Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA;
6. Columbia University Medical Center, New York, NY, USA