1. Department of Social Medicine, Toho University Graduate School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo, Japan
2. Chiba Psychiatric Medical Center, 5 Toyosuna, Mihama-ku, Chiba-shi, Chiba, Japan
3. Department of Social Medicine, Toho University School of Medicine, 5-21-16, Omori-nishi, Ota-ku, Tokyo, Japan