Abstract：
A fire in one of the Windscale nuclear reactors at Sellafield (Cumbria, England) in October 1957 released 1,800 TBq of 131I (half-life, 8 days) to atmosphere. Measurements of 131I 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 131I 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 131I. Three areas of Cumbria with different 131I 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 131I 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 131I 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 131I, such as occurred following the Fukushima nuclear accident in 2011.
摘要：
塞拉菲尔德（坎布里亚郡，英格兰)于1957年10月发布了1800TBq的131I(半衰期，8天）到大气。暴露儿童甲状腺中131I活性的测量显示典型的甲状腺剂量为几十毫格雷，但有些超过100毫克。众所周知，儿童时期的辐射暴露会增加患甲状腺癌的风险。因此,在坎布里亚郡进行了一项调查,调查了在幼儿时期接触131I的人群中,甲状腺癌病例的数量是否增加.自1950年以来的坎布里亚出生人口数据库允许建立1950-1958年期间的56,086名出生人口和1959-1980年期间的137,444名出生人口。包括可能暴露和未暴露的儿童在内的时期，分别,131I从监测数据中确定了坎布里亚郡三个具有不同131I污染水平的地区，和出生分配到这三个地区的两个出生时期。这六个子队列的成员使用国家癌症登记数据库与1981-2020年英国的甲状腺癌事件病例相关联。提供甲状腺癌发病率。发病率比率（IRR），以污染最低的区域作为参考，是计算的。没有IRR与统一有明显的区别。对于1950-1958年的出生，最高和中间131I污染区域的IRR为0.68（95％置信区间：0.24，1.56），在最高污染地区出生的小队列中未发现甲状腺癌病例。总之,1957年在坎布里亚郡未发现131I暴露者患甲状腺癌的风险增加.这项研究增加了儿童暴露于低和中等水平131I后甲状腺癌长期风险的证据，例如2011年福岛核事故之后发生的。
