1. Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea.
2. Department of Preventive Medicine & Public Health, Ajou University School of Medicine, Suwon, Korea.
3. Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
4. Department of Internal Medicine, Dong-A University School of Medicine, Busan, Korea.
5. Department of Internal Medicine, Hallym University School of Medicine, Anyang, Korea.
6. Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.