Guangdong Academy of Medical Sciences - Department of Gastroenterology, University of Oxford, Southern Medical University, Guangdong Academy of Medical Sciences - Department of Gastroenterology, Guangdong Academy of Medical Sciences - Department of Gastroenterology, Southern Medical University, Guangdong Academy of Medical Sciences - Department of Gastroenterology, Southern Medical University, Southern Medical University, Guangdong Academy of Medical Sciences - Department of Gastroenterology, Guangdong Academy of Medical Sciences, Guangdong Academy of Medical Sciences - Department of Gastroenterology, Southern Medical University, The University of Hong Kong - State Key Laboratory of Pharmaceutical Biotechnology, University of Oxford, Peking University - Department of Epidemiology and Biostatistics, Peking University - Department of Epidemiology and Biostatistics, Peking University Health Science Center - School of Public Health, Peking University - Department of Epidemiology and Biostatistics, Chinese Academy of Medical Sciences, University of California, Los Angeles (UCLA), Guangdong Academy of Medical Sciences - Department of Gastroenterology, University of Oxford - Clinical Trial Service Unit and Epidemiological Studies Unit and Guangdong Academy of Medical Sciences - Department of Gastroenterology