1. Division of Pulmonology, Allergy and Critical Care Medicine, Department of Internal Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, Korea.
2. Department of Statistics, Keimyung University, Daegu, Korea.
3. Division of Allergy and Immunology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
4. Institute of Allergy, Yonsei University College of Medicine, Seoul, Korea.