Shuko Takahashi1, Soong-Nang Jang2, Shiho Kino3, Ichiro Kawachi3. 1. Takemi Program in International Health, Harvard T.H. Chan School of Public Health, 665 Huntington Avenue, Building 1, Room 1210A, Boston, MA, 02115, USA; International Health, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan; Division of Medical Education, Iwate Medical University, 2-1-1, Nishitokuta, Yahaba-cho, Shiwa-gun, Iwate, 028-3694, Japan. 2. Red Cross College of Nursing, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu Seoul, 06709, South Korea; Department of Social and Behavioral Sciences, Harvard. T.H. Chan School of Public Health, 401 Park Drive, Boston, MA, 02215, USA. Electronic address: sjang@cau.ac.kr. 3. Department of Social and Behavioral Sciences, Harvard. T.H. Chan School of Public Health, 401 Park Drive, Boston, MA, 02215, USA.