1. Department of Gastroenterology, Guangzhou First People's Hospital; Guangzhou Medical University; Guangdong Province China
2. Department of Epidemiology; Guangzhou Nansha Central Hospital, Guangzhou First People's Hospital; Guangzhou Guangdong Province China
3. Department of Gastroenterology; Guangzhou Nansha Central Hospital, Guangzhou First People's Hospital; Guangzhou Guangdong Province China