1. Department of Epidemiology; Nagasaki Laboratory; Radiation Effects Research Foundation; Nagasaki; Japan
2. Department of Hematology; Atomic Bomb Disease Institute; Nagasaki University; Nagasaki; Japan
3. Division of Epidemiology and Prevention; Aichi Cancer Center Research Institute; Nagoya; Japan
4. Cancer Information Services and Surveillance Division; Center for Cancer Control and Information Services; National Cancer Center; Tokyo; Japan
5. Division of Environmental Medicine and Population Sciences; Graduate School of Medicine; Osaka University; Osaka; Japan