1. Division of Gastroenterology, Aichi Medical University, Nagakute 480-1195, Japan
2. Division of General Medicine, Aichi Medical University, Nagakute 480-1195, Japan
3. Division of Biostatistics, Clinical Research Center, Aichi Medical University, Nagakute 480-1195, Japan
4. Division of Sleep Medicine, Aichi Medical University, Nagakute 480-1195, Japan