1. From the Institute for Health Promotion (J.W.S., H.O.), Graduate School of Public Health, Yonsei University, Seoul, Korea; the Department of Preventive Medicine and Public Health (S.-W.Y.), Kwandong University College of Medicine, Gangneung, Korea; and the Department of Preventive Medicine (C.M.N., H.O.), Yonsei University College of Medicine, Seoul, Korea.