1. Department of Biostatistics, College of Medicine, Korea University, Korea
2. Department of Statistics, University of Wisconsin-Madison, USA
3. Department of Preventive Medicine (Biostatistics), Feinberg School of Medicine, Northwestern University, USA
4. Department of Internal Medicine, Kyung Hee University School of Medicine, Korea
5. Department of Gastroenterology, Liver Center, Asan Medical Center, University of Ulsan College of Medicine, Korea