to join the Niigata Asthma Treatment Study Group The study was performed with the approval of the Ethics Committee at the School of Medicine of Nii-gata University (approval #1090) in Niigata Prefec-ture, Japan, in accordance with the Ethical Principles for Medical Research Involving Human Subjects(Declaration of Helsinki). Written informed consent to participate was obtained from all patients. The questionnaire was written in Japanese. The question-naire survey was administered between September and October 2010.