1. Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo 693-8501, Japan
2. Oda Municipal Hospital, 1428-3 Yoshinaga, Oda-cho, Oda 694-0063, Japan
3. Community Care, Unnan City Hospital, 699-1221 96-1 Iida, Daito-cho, Unnan 699-1221, Japan
4. Department of Community Medicine Management, Faculty of Medicine, Shimane University, 89-1 Enya cho, Izumo 693-8501, Japan