Epidemiology. 2018 Jan;29(1):31-40. doi: 10.1097/EDE.0000000000000761.
There is considerable scientific interest in associations between protracted low-dose exposure to ionizing radiation and the occurrence of specific types of cancer.
Associations between ionizing radiation and site-specific solid cancer mortality were examined among 308,297 nuclear workers employed in France, the United Kingdom, and the United States. Workers were monitored for external radiation exposure and follow-up encompassed 8.2 million person-years. Radiation-mortality associations were estimated using a maximum-likelihood method and using a Markov chain Monte Carlo method, the latter used to fit a hierarchical regression model to stabilize estimates of association.
The analysis included 17,957 deaths attributable to solid cancer, the most common being lung, prostate, and colon cancer. Using a maximum-likelihood method to quantify associations between radiation dose- and site-specific cancer, we obtained positive point estimates for oral, esophagus, stomach, colon, rectum, pancreas, peritoneum, larynx, lung, pleura, bone and connective tissue, skin, ovary, testis, and thyroid cancer; in addition, we obtained negative point estimates for cancer of the liver and gallbladder, prostate, bladder, kidney, and brain. Most of these estimated coefficients exhibited substantial imprecision. Employing a hierarchical model for stabilization had little impact on the estimated associations for the most commonly observed outcomes, but for less frequent cancer types, the stabilized estimates tended to take less extreme values and have greater precision than estimates obtained without such stabilization.
The results provide further evidence regarding associations between low-dose radiation exposure and cancer.
人们对低剂量、长时间暴露于电离辐射与特定类型癌症发生之间的关联有着浓厚的科学兴趣。
在法国、英国和美国，308297 名核工作者参与了本研究，研究人员对电离辐射与特定部位实体癌死亡率之间的关联进行了调查。工作人员接受了外部辐射暴露监测，随访时间涵盖 820 万人年。采用最大似然法和马尔可夫链蒙特卡罗法来估计辐射与死亡率之间的关联，后者用于拟合分层回归模型以稳定关联的估计值。
该分析包括 17957 例归因于实体癌的死亡，最常见的是肺癌、前列腺癌和结肠癌。采用最大似然法来量化辐射剂量与特定部位癌症之间的关联，我们得出了口腔癌、食管癌、胃癌、结肠癌、直肠癌、胰腺癌、腹膜癌、喉癌、肺癌、胸膜癌、骨癌和结缔组织癌、皮肤癌、卵巢癌、睾丸癌和甲状腺癌的阳性点估计值；此外，我们还得到了肝癌和胆囊癌、前列腺癌、膀胱癌、肾癌和脑癌的阴性点估计值。这些估计系数大多存在较大的不精确性。采用分层模型进行稳定化对最常见观察结果的估计关联几乎没有影响，但对于不太常见的癌症类型，稳定化估计值往往取值不那么极端，且比没有进行这种稳定化处理的估计值具有更高的精度。
这些结果为低剂量辐射暴露与癌症之间的关联提供了进一步的证据。
