Shakhtarin V V, Tsyb A F, Stepanenko V F, Orlov M Y, Kopecky K J, Davis S
Medical Radiological Research Center of the Russian Academy of Medical Sciences, Obninsk, Russia.
Int J Epidemiol. 2003 Aug;32(4):584-91. doi: 10.1093/ije/dyg205.
Little is known about the joint effect of iodine deficiency and radiation exposure on the risk of thyroid cancer. No epidemiological studies have been published assessing the modifying effect of iodine deficiency on radiation-induced thyroid cancer following the Chernobyl accident.
A population sample of 3070 individuals (2590 ages 6-18, and 480 adults) from 75 settlements in the most highly contaminated regions of the Bryansk Oblast of Russia was identified and sampled for urinary iodine measurements in 1996, and iodine deficiency in each geopolitical unit (raion) was estimated. All cases of thyroid cancer were identified in those born 1968-1986 who were resident in the study area in May-June 1986 (34 histologically confirmed cases). The risk of thyroid cancer was examined in relation to population estimates of thyroid radiation dose and urinary iodine excretion level.
The excess relative risk (ERR) of thyroid cancer was significantly associated with increasing thyroid radiation dose, and was inversely associated with urinary iodine excretion levels. There was a joint effect of radiation exposure and iodine deficiency. At 1 gray (Gy), the ERR in territories with severe iodine deficiency was approximately two times that in areas of normal iodine intake.
These findings suggest that elimination of iodine deficiency in areas affected by Chernobyl may be important in reducing the effects of radiation exposure on the thyroid. If confirmed by studies based on individuals, they may have implications for the use of stable iodine in the case of population exposure to radioactive iodine.
碘缺乏与辐射暴露对甲状腺癌风险的联合影响鲜为人知。尚无已发表的流行病学研究评估碘缺乏对切尔诺贝利事故后辐射诱发甲状腺癌的修饰作用。
在俄罗斯布良斯克州污染最严重地区的75个定居点中，确定了3070名个体的人群样本（2590名6 - 18岁，480名成年人），并于1996年对其进行采样以测量尿碘，同时估算每个地缘政治单位（区）的碘缺乏情况。在1968 - 1986年出生且于1986年5 - 6月居住在研究区域的人群中识别出所有甲状腺癌病例（34例经组织学确诊）。研究了甲状腺癌风险与人群甲状腺辐射剂量估计值及尿碘排泄水平之间的关系。
甲状腺癌的超额相对风险（ERR）与甲状腺辐射剂量增加显著相关，且与尿碘排泄水平呈负相关。存在辐射暴露与碘缺乏的联合效应。在1戈瑞（Gy）时，碘严重缺乏地区的ERR约为碘摄入正常地区的两倍。
这些发现表明，消除切尔诺贝利事故影响地区的碘缺乏对于减轻辐射暴露对甲状腺的影响可能很重要。如果基于个体的研究证实了这些结果，那么在人群暴露于放射性碘的情况下，它们可能对稳定碘的使用具有启示意义。
