1. Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
2. Department of General Surgery, Tan Tock Seng Hospital, Singapore 637551, Singapore
3. Department of Gastroenterology and Hepatology, Tan Tock Seng Hospital, Singapore 637551, Singapore
4. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore