[1] Yokohama City Univ, Grad Sch Med, Dept Community Hlth Nursing, Kanazawa Ku, 3-9 Fukuura, Yokohama, Kanagawa 2360004, Japan
[2] Hokkaido Univ, Grad Sch Hlth Sci, Dept Community & Publ Hlth Nursing, Kita Ku, N12 W5, Sapporo, Hokkaido 0600812, Japan
[3] Hokkaido Univ, Fac Med, Kita Ku, N12 W5, Sapporo, Hokkaido 0600812, Japan