1. Department of Internal Medicine, Graduate School of Life Dentistry at Niigata, Nippon Dental University, Niigata, Japan
2. Center for Dental Sleep Medicine, Nippon Dental University Niigata Hospital, Niigata, Japan
3. Department of Oral and Maxillofacial Surgery, School of Life Dentistry at Niigata, Nippon Dental University, Niigata, Japan
4. Department of Internal Medicine, School of Life Dentistry at Niigata, Nippon Dental University, Niigata, Japan