1. Department of Gastrointestinal Surgery; The First Affiliated Hospital of Chongqing Medical University; Chongqing China
2. Division of Endocrinology, Diabetes and Nutrition, Department of Medicine; University of Maryland School of Medicine; Baltimore MD USA
3. Department of Endocrinology and Metabolism Disease; Kunshan Hospital of Jiangsu University; Jiangsu China
4. VA Research Service, Geriatric Research, Education and Clinical Center; Baltimore Veterans Administration Medical Center; Baltimore USA