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 Principlesfor 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.