1. Department of Epidemiology and statistics; School of Public Health; Hebei Medical University; Shijiazhuang China
2. Department of Social Medicine and Health Care Management; School of Public Health; Hebei Medical University; Shijiazhuang China
3. Division of gastroenterology; The Second Hospital of Hebei Medical University; The Hebei Key Laboratory of Gastroenterology; Shijiazhuang China
4. Fourth Department of Cardiology; TangShan GongRen Hospital; TangShan China