1. Department of Respiratory Therapy, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan
2. Department of Respiratory Care, Chang Gung University of Science and Technology, Chiayi 600, Taiwan
3. Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Chiayi 600, Taiwan
4. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan
5. College of Medicine, Chang Gung University, Taoyuan 333, Taiwan