1. From the Department of Community Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata City, Japan (KN, YO, YT, and MY); the Department of Nursing, School of Health Sciences, Niigata University, Niigata City, Japan (KU and TN); and the Department of Health and Nutrition, Niigata University of Health and Welfare, Niigata City, Japan (TS)