1. Division of Pulmonology, Allergy, and Critical Care Medicine, Research Institute for Convergence of Biomedical Science and Technology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
2. Department of Internal Medicine, School of Medicine, Pusan National University, Yangsan-si, Republic of Korea
3. Family Medicine Clinic and Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
4. College of Nursing, Research Institute of Nursing Science, Pusan National University, Yangsan, Republic of Korea
5. Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, WA, USA
6. Department of Family Medicine, Pusan National University School of Medicine, Yangsan, South Korea