1. School of Public Health, Jilin University, Jilin, P. R. China
2. Department of Gastroenterology, Affiliated Shenzhen Hospital, Shanghai University of Traditional Chinese Medicine, Guangdong, P. R. China
3. School of Clinical Medicine, Beijing University of Chinese Medicine, Beijing, P. R. China
4. Department of Gastroenterology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, P. R. China
5. Department of Gastroenterology, Guang’anmen Hospital, Chinese Academy of Traditional Chinese Medicine, Beijing, P. R. China