1. Department of Gastroenterology; The First Affiliated Hospital of Sun Yat-sen University; Guangzhou Guangdong China
2. Department of Gastroenterology; Zhongshan People's Hospital; Zhongshan Guangdong China
3. Anorectal Department; Zhongshan Hospital of Traditional Chinese Medicine; Zhongshan Guangdong China
4. Department of Gastroenterology; Zhongshan Boai Hospital; Zhongshan Guangdong China
5. Department of Gastroenterology; Zhongshan Xiaolan Hospital; Zhongshan Guangdong China
6. School of Public Health; Sun Yat-sen University; Guangzhou Guangdong China
7. Department of Gastroenterology; Peking Union Medical College Hospital; Beijing China
8. Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Science; Prince of Wales Hospital, Chinese University of Hong Kong; Hong Kong China