1. Department of Work Systems and HealthInstitute of Industrial Ecological Sciences, University of Occupational and Environmental HealthJapan
2. Department of Preventive Medicine and Public HealthKitasato University School of Medicine
3. Institute for Science of Labour, University of Occupational and Environmental HealthJapan
4. Fukuoka Occupational Health Promotion CenterUniversity of Occupational and Environmental HealthJapan
5. Department of MicrobiologyUniversity of Occupational and Environmental HealthJapan