Yoshio Yamaoka1,2. 1. Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Hasama-machi, Yufu, Oita Prefecture, Japan. yyamaoka@oita-u.ac.jp. 2. Department of Medicine, Baylor College of Medicine, Houston, TX, USA. yyamaoka@oita-u.ac.jp.