1. Department of General Medicine, National Defense Medical College, Tokorozawa, Japan
2. Division of Environmental Medicine, National Defense Medical College Research Institute, National Defense Medical College, Tokorozawa, Japan
3. Second Division, Aeromedical Laboratory, Air Development and Test Command, Japan Air Self-Defense Force, Tachikawa, Japan
4. Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan
5. Department of Laboratory Medicine, National Defense Medical College Hospital, Tokorozawa, Japan