1. Department of Community Health Nursing, School of Nursing and Social Services, Health Sciences, University of Hokkaido, Tobetsu-cho, Ishikari-gun 061-0293, Japan
2. Department of Community Health Nursing, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
3. Department of Community and Public Health Nursing, Graduate School of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan