1. a Biometrics Department , Chugai Clinical Research Center Co., Ltd. , Chuo-ku, Tokyo, Japan
2. b Division of Biostatistics , Kitasato University Graduate School , Minato-ku, Tokyo, Japan
3. c Department of Hygiene and Public Health , Teikyo University of Medicine , Itabashi-ku, Tokyo, Japan
4. d Clinic Sendagaya , Shibuya-ku, Tokyo, Japan