1. Graduate School of Health Sciences, Hokkaido University, Sapporo, Japan
2. Faculty of Health Sciences, Hokkaido University, Sapporo, Japan
3. Graduate School of Commerce, Otaru University of Commerce, Otaru, Japan
4. Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
5. Center for Outcomes Research and Economic Evaluation for Health, National Institute of Public Health, Wako, Japan
6. Faculty of Health Sciences, Hokkaido University of Science, Sapporo, Japan
7. Faculty of Engineering, Muroran Institute of Technology, Muroran, Japan