Nuclear epidemiologic studies and the estimation of DREF
Nuclear epidemiologic studies and the estimation of DREF
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DOI：
10.1080/09553002.2018.1437483
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发表时间：
2018-01-01
影响因子：
2.6
通讯作者：
Hoel, David G.
中科院分区：
文献类型：
--
作者：
Hoel, David G.
目的：根据急性辐照数据估算连续辐照的癌症风险一直是一个重要的公共卫生问题。剂量和剂量率有效性因子（DDREF）通常用于根据急性照射的风险估计来估计慢性照射的癌症风险。ICRP在ICRP 60中建议的DDREF值2最常使用;然而，对几个队列进行的有影响力的分析得出结论，急性和慢性暴露之间没有风险差异。这篇文章的目的是分析最近的核工作者的研究和估计剂量率有效性因子，DREF，为固体癌症。材料和方法：确定了12项死亡率研究，每项研究至少有100例癌症死亡，然后使用低剂量率癌症效应（LDR）与原子弹队列（LSS）相应的高剂量率效应的个体比率进行荟萃分析。结果：Q=0.36（95%CI =0.11，0.60），DREF=2.63（95%CI =1.61，7.14）。显然，该估计值与DREF为2比与DREF为1更一致。估计Q=0.36的困难在于，它仅由两项大型且不同的工人研究驱动，即INWORKS研究（q（1）=1.14）和Mayak工人队列（q（3）=0.30）。这些核工作人员的较高暴露通常发生在早期（例如1960年之前），中子和内部发射体的暴露未包括在风险分析中，导致可能高估每剂量的癌症效应，这将增加DREF的估计值。然而，Mayak的研究确实对钚暴露进行了调整。最后，考虑到其他队列研究，DREF值可能会被确定，如环境暴露的Techa河地区的居民和切尔诺贝利清理工人以及医疗X射线工作者。虽然不相似的总体荟萃分析得出Q=0.45（95%CI =0.24，0.66）。结论：可以得出结论，DREF的最佳估计值仍然约为2。然而，由于流行病学研究存在各种问题，特别是其剂量测定，因此得出结论，应相当谨慎地接受约为2的DREF，因为它仅由Mayak研究驱动。
Purpose: Estimating cancer risks for continuous radiation exposures based upon data from acute exposures has been an important public health problem. A dose and dose rate effectiveness factor (DDREF) is typically used to estimate cancer risks for chronic exposures based upon risk estimates from acute exposures. A value of 2 for a DDREF has most often been used as proposed by the ICRP in ICRP60; however, an influential analysis of several cohorts concluded that there is no risk difference between acute and chronic exposures. It is the purpose of this article to analyze the recent nuclear worker studies and estimate the dose rate effectiveness factor, DREF, for solid cancers.Materials and methods: Twelve mortality studies were identified each with at least 100 cancer deaths and a meta-analysis was then carried out using their individual ratio of low dose rate cancer effect (LDR) to the corresponding high dose rate effect from the A-bomb cohort (LSS). The ratio is denoted by Q and its reciprocal is then an estimate of the DREF.Results: The result was Q=0.36 (95% CI=0.11, 0.60) and DREF=2.63 (95% confidence interval [CI]=1.61, 7.14). Clearly, this estimate is more consistent with a DREF of 2 than with a DREF of 1. The difficulty with the estimate Q=0.36 is that it is driven by only two large and dissimilar worker studies, the INWORKS study (q(1)=1.14) and the Mayak worker cohort (q(3)=0.30). The higher exposures for these nuclear workers were often in the early years (e.g. before 1960) with exposures from neutrons and internal emitters that are not included in the risk analyses resulting in likely overestimation of cancer effects per dose which would increase the estimate of the DREF. The Mayak study did, however, adjust for plutonium exposures. Finally, consideration is given to other cohort studies where DREF values may possibly be determined, such as the environmental exposures to the Techa River area residents and the Chernobyl cleanup workers as well as medical X-ray workers. Although dissimilar an overall meta-analysis yielded a Q=0.45 (95% CI=0.24, 0.66).Conclusions: It is concluded that the best estimate of a DREF is still about 2. However, because of the various problems with the epidemiology studies, especially their dosimetry, it is concluded that a DREF of about 2 should be accepted with considerable caution since it is driven solely by the Mayak study.