1. Department of General Internal Medicine, Shonan Kamakura General Hospital, Kamakura, Japan.
2. Unit of Public Health and Preventive Medicine, Yokohama City University, Yokohama, Japan.
3. Department of Internal Medicine, Hayama Heart Center, Miura, Japan.
4. Department of Biostatistics, Yokohama City University School of Medicine, Yokohama, Japan.
5. Department of Medical Education, Yokohama City University, Yokohama, Japan.