1. Department of Public Health, Graduate School, Korea University, Seoul, Korea.
2. Department of Health Policy and Hospital Management, Graduate School of Public Health, Korea University, Seoul, Korea.
3. Department of Nursing, Cheju Halla College, Jeju, Korea.
4. Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Korea.
5. Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul, Korea.