[1] Osaka City Univ, Dept Publ Hlth Nursing, Osaka 5450051, Japan
[2] Nagasaki Univ, Nagasaki 852, Japan
[3] Tohoku Univ, Sch Med, Sendai, Miyagi 980, Japan
[4] Iwate Prefectural Univ, Takizawa, Iwate, Japan
[5] Teikyo Univ, Tokyo 173, Japan
[6] Kyorin Univ, Tokyo, Japan
[7] Fukushima Prefectural Sch Nursing, Fukushima, Japan
[8] Japanese Nursing Assoc, Tokyo, Japan
[9] Natl Inst Publ Hlth, Saitama, Japan