1. Department of Allergy and Clinical Immunology, Kangwon National University School of Medicine, Chuncheon, Korea.
2. Department of Internal Medicine and Environmental Health Center, Kangwon National University Hospital, Chuncheon, Korea.
3. Department of Environmental Science, Kangwon National University, Chuncheon, Korea.
4. Department of Preventive Medicine, Kangwon National University Hospital, Chuncheon, Korea.
5. Department of Internal Medicine, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Korea.
6. Department of Biostatistics, Graduate School of Public Health, Seoul National University, Seoul, Korea.