1. Department of Public Health, Graduate School, Korea University, Seoul, Korea.
2. Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul, Korea.
3. Department of Nursing, Pyeongtaek University, Pyeongtaek, Korea.
4. Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Korea.
5. Department of Preventive Medicine, University of Ulsan College of Medicine, Seoul, Korea.
6. Department of Preventive Medicine, School of Medicine, Ewha Womans University, Seoul, Korea.
7. Department of Social and Preventive Medicine, Inha University School of Medicine, Incheon, Korea.