1. Department of Preventive Medicine, School of Medicine Kangwon National University, Chuncheon, Korea.
2. Department of Benefits Strategy, National Health Insurance Service, Wonju, Korea.
3. Department of Preventive Medicine, Korea University Medical College, Seoul, Korea.
4. Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, Korea.
5. Department of Statistics, College of Business Administration, Kangwon National University, Chuncheon, Korea.