1. doctoral student, Department of Community Health Nursing, Division of Health Sciences and Nursing, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo Bunkyo-ku, Tokyo 113, Japan
2. Assistant Professor, Department of Community Health Nursing, Division of Health Sciences and Nursing, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo Bunkyo-ku, Tokyo 113, Japan
3. Associate Professor, Department of Community Health Nursing, Division of Health Sciences and Nursing, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo Bunkyo-ku, Tokyo 113, Japan