1. Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan
2. Division of Biomedical Statistics, Department of Integrated Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka 565‑0871, Japan
3. Center for Comprehensive Community Medicine, Faculty of Medicine, Saga University, Saga 849‑0937, Japan