1. International Institute of Health, No. 402, 30 Digital-ro 32-gil, Guro-gu, Seoul 152-777, Republic of Korea
2. Department of Public Health, Daegu Haany University, 1 Haanydaero, Gyeongsan-si, Gyeongsangbuk-do 712-715, Republic of Korea
3. Department of Humanities and Social Medicine, College of Medicine and Catholic Institute for Healthcare Management, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701, Republic of Korea