1. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
2. Department of Gastroenterology and Hepatology, Guangzhou Eighth People’s Hospital, Guangzhou, Guangdong Province, China
3. Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
4. Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland, USA