1. Department of Social and Preventive Medicine, College of Medicine, Health Services Research Center, Hallym University, Korea.
2. Department of Preventive Medicine, Institute of Health Science, Gyeongsang National University, Korea.
3. School of Public Health, Seoul National University, Korea.
4. Division of Occupational and Environmental Medicine, KyungHee University Medical Center, Korea.
5. Institute of Health and Environment, Seoul National University, Korea.
6. Department of Public Administration, College of Social Sciences, Ewha Womans University, Korea.
7. Department of Preventive Medicine, University of Ulsan College of Medicine, Korea.