Population Health Sciences Institute & Newcastle University Centre for Cancer, Sir James Spence Institute, Newcastle University, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK.
Centre for Occupational and Environmental Health, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
Radiat Environ Biophys. 2024 Nov;63(4):491-503. doi: 10.1007/s00411-024-01087-y. Epub 2024 Aug 16.
A fire in one of the Windscale nuclear reactors at Sellafield (Cumbria, England) in October 1957 released 1,800 TBq of I (half-life, 8 days) to atmosphere. Measurements of I activity in thyroids of exposed children showed typical thyroid doses of tens of milligray, but with some exceeding 100 mGy. Radiation exposure in childhood is known to increase the risk of thyroid cancer. Consequently, an investigation was conducted into whether raised numbers of thyroid cancer cases occurred in those exposed to I as young children in Cumbria. A database of Cumbrian births from 1950 onwards allowed cohorts of 56,086 births during 1950-1958 and 137,444 births during 1959-1980 to be constructed, periods including children potentially exposed and unexposed, respectively, to I. Three areas of Cumbria with different I contamination levels were identified from monitoring data, and births assigned to these three areas for the two periods of birth. Members of these six sub-cohorts were linked to incident thyroid cancer cases in Great Britain during 1981-2020 using national cancer registration databases, providing thyroid cancer incidence rates. Incidence rate ratios (IRRs), with the lowest contamination area as a reference, were computed. No IRR differed discernibly from unity. For births during 1950-1958, the IRR for the combined highest and intermediate I contamination areas was 0.68 (95% confidence interval: 0.24, 1.56), and no case of thyroid cancer was found in the small cohort born in the highest contamination area. In conclusion, no increased risk of thyroid cancer in those exposed to I as young children in Cumbria in 1957 was detected. This study adds to the evidence on the long-term risk of thyroid cancer following childhood exposure to low and moderate levels of I, such as occurred following the Fukushima nuclear accident in 2011.
1957 年 10 月，英格兰坎布里亚郡塞拉菲尔德的温斯凯尔（Windscale）核反应堆发生火灾，向大气中释放了 1800TBq 的碘-131（半衰期 8 天）。对暴露于碘-131 的儿童甲状腺中碘-131 活性的测量显示，典型的甲状腺剂量为数十毫戈瑞，但有些超过 100 毫戈瑞。已知儿童期辐射暴露会增加患甲状腺癌的风险。因此，对暴露于 1957 年儿童时期的碘-131 的坎布里亚郡儿童是否发生了更多甲状腺癌病例进行了调查。1950 年以后的坎布里亚郡出生数据库允许构建了两个队列，分别为 1950-1958 年期间的 56086 名出生和 1959-1980 年期间的 137444 名出生，这两个时期分别包括可能接触和未接触碘-131 的儿童。从监测数据中确定了坎布里亚郡的三个具有不同碘-131 污染水平的地区，并将这两个时期的出生分配到这三个地区。使用全国癌症登记数据库将这些六个子队列的成员与 1981-2020 年期间英国的甲状腺癌病例联系起来，提供甲状腺癌发病率。计算了发病率比（IRR），以污染程度最低的地区为参考。没有 IRR 明显不同于 1。对于 1950-1958 年期间的出生，最高和中等碘-131 污染区的合并 IRR 为 0.68（95%置信区间：0.24，1.56），而且在污染最严重的地区出生的小队列中没有发现甲状腺癌病例。总之，在 1957 年，坎布里亚郡的儿童暴露于碘-131 并没有检测到甲状腺癌风险增加。这项研究增加了关于儿童期接触低水平和中等水平碘-131 后发生甲状腺癌的长期风险的证据，例如 2011 年福岛核事故后发生的情况。
