School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan. Department of Family Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan. Department of Family Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan. Division of Gastroenterology and Hepatology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.