1. John Sealy School of Medicine (JSSM), University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA
2. Department of Family Medicine, John Sealy School of Medicine (JSSM), University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA
3. Department of Internal Medicine, Division of Endocrinology, John Sealy School of Medicine (JSSM), University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA
4. Department of Medical Physiology, Faculty of Medicine, Suez Canal University, Ismailia 41522, Egypt
5. Department of Internal Medicine, Division of Cardiology, John Sealy School of Medicine (JSSM), University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA