1. Heewon Kang, PhD, MPH, Institute of Health and Environment, Graduate School of Public Health. Seoul National University, Seoul, Republic of Korea.
2. Sangwoo Tak, ScD, MPH, are Research Professors, Institute of Health and Environment, Graduate School of Public Health. Seoul National University, Seoul, Republic of Korea.
3. Su Jin Kang, PhD, is a Senior Research Associate, Institute of Health and Environment, Graduate School of Public Health. Seoul National University, Seoul, Republic of Korea.