Nobuyuki Taniguchi1, Naomi Hayashida2, Hiroki Shimura3, Noriyuki Okubo4, Yasushi Asari5, Takeshi Nigawara6, Sanae Midorikawa7, Kazuhiko Kotani8, Shigeyuki Nakaji4, Misa Imaizumi9, Akira Ohtsuru7, Takashi Akamizu10, Masafumi Kitaoka11, Shinichi Suzuki12, Shunichi Yamashita13,14, Noboru Takamura2. 1. Department of Clinical Laboratory Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. taniguch@jichi.ac.jp. 2. Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. 3. Department of Environmental Internal Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan. 4. Department of Social Medicine, Hirosaki University Graduate School of Medicine, Aomori, Japan. 5. Department of Emergency and Disaster Medicine, Hirosaki University Graduate School of Medicine, Aomori, Japan. 6. Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Aomori, Japan. 7. Department of Radiation Health Management, Fukushima Medical University, Fukushima, Japan. 8. Department of Clinical Laboratory Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. 9. Department of Clinical Studies, Radiation Effects Research Foundation, Nagasaki, Japan. 10. The First Department of Medicine, Wakayama Medical University, Wakayama, Japan. 11. Division of Endocrinology and Metabolism, Showa General Hospital, Tokyo, Japan. 12. Department of Organ Regulator Surgery, Fukushima Medical University, Fukushima, Japan. 13. Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. 14. Radiation Science Center for Fukushima Health Management Survey, Fukushima Medical University, Fukushima, Japan.
Abstract
PURPOSE: The Fukushima Health Management Survey conducted after the accident at the Fukushima Nuclear Power Plant included thyroid ultrasound examinations for children aged ≤18 years at the time of the accident. The purpose of this study was to investigate the frequency of thyroid nodular lesions detected using high-quality ultrasonography in a general population of Japanese children, in whom such data have not been previously characterized. METHODS: The current study investigated 4,365 free-living children aged between 3 and 18 years in three Japanese prefectures (Aomori, Yamanashi and Nagasaki). The same ultrasonography equipment as that used in the Fukushima Survey was employed to observe thyroid nodular lesions. The following categories of findings were used-'A', further examinations are not necessary; 'B', the presence of thyroid nodules with a diameter of ≥5.1 mm or thyroid cysts with a diameter of ≥20.1 mm; and 'C', immediate further examinations are required. As a sub-category of 'A', 'A1' was defined as the absence of nodules or cysts, and 'A2' was defined as the presence of thyroid nodules with a diameter of ≤5.0 mm or thyroid cysts with a diameter of ≤20.0 mm. RESULTS: Overall, 4,321 (99 %) of the total participants were classified with a status of 'A' and 44 (1 %) were classified with a status of 'B'. No participants were classified with a status of 'C'. A total of 56.5 % of the total participants was classified with a status of 'A2'. Thyroid nodules were identified in 1.6 % of the total participants and thyroid cysts were identified in 56.9 % of the participants. CONCLUSION: The current study provides data regarding the actual frequency of ultrasonographically detected thyroid nodular lesions among the Japanese children. These results would be useful for evaluating thyroid findings in Japanese children, although careful interpretation is required.
PURPOSE: The Fukushima Health Management Survey conducted after the accident at the Fukushima Nuclear Power Plant included thyroid ultrasound examinations for children aged ≤18 years at the time of the accident. The purpose of this study was to investigate the frequency of thyroid nodular lesions detected using high-quality ultrasonography in a general population of Japanese children, in whom such data have not been previously characterized. METHODS: The current study investigated 4,365 free-living children aged between 3 and 18 years in three Japanese prefectures (Aomori, Yamanashi and Nagasaki). The same ultrasonography equipment as that used in the Fukushima Survey was employed to observe thyroid nodular lesions. The following categories of findings were used-'A', further examinations are not necessary; 'B', the presence of thyroid nodules with a diameter of ≥5.1 mm or thyroid cysts with a diameter of ≥20.1 mm; and 'C', immediate further examinations are required. As a sub-category of 'A', 'A1' was defined as the absence of nodules or cysts, and 'A2' was defined as the presence of thyroid nodules with a diameter of ≤5.0 mm or thyroid cysts with a diameter of ≤20.0 mm. RESULTS: Overall, 4,321 (99 %) of the total participants were classified with a status of 'A' and 44 (1 %) were classified with a status of 'B'. No participants were classified with a status of 'C'. A total of 56.5 % of the total participants was classified with a status of 'A2'. Thyroid nodules were identified in 1.6 % of the total participants and thyroid cysts were identified in 56.9 % of the participants. CONCLUSION: The current study provides data regarding the actual frequency of ultrasonographically detected thyroid nodular lesions among the Japanese children. These results would be useful for evaluating thyroid findings in Japanese children, although careful interpretation is required.