1. Department of Gastroenterology, Kitakyushu Municipal Medical Center, Kitakyushu, Fukuoka, Japan
2. Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
3. Department of Gastroenterology and Metabolism, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan