Division of Cancer Epidemiology & Genetics, Radiation Epidemiology Branch, Bethesda, MD, USA.
National Institute for Occupational Safety and Health, Cincinnati, OH, USA.
J Natl Cancer Inst Monogr. 2020 Jul 1;2020(56):97-113. doi: 10.1093/jncimonographs/lgaa009.
Whether low-dose ionizing radiation can cause cancer is a critical and long-debated question in radiation protection. Since the Biological Effects of Ionizing Radiation report by the National Academies in 2006, new publications from large, well-powered epidemiological studies of low doses have reported positive dose-response relationships. It has been suggested, however, that biases could explain these findings. We conducted a systematic review of epidemiological studies with mean doses less than 100 mGy published 2006-2017. We required individualized doses and dose-response estimates with confidence intervals. We identified 26 eligible studies (eight environmental, four medical, and 14 occupational), including 91 000 solid cancers and 13 000 leukemias. Mean doses ranged from 0.1 to 82 mGy. The excess relative risk at 100 mGy was positive for 16 of 22 solid cancer studies and 17 of 20 leukemia studies. The aim of this monograph was to systematically review the potential biases in these studies (including dose uncertainty, confounding, and outcome misclassification) and to assess whether the subset of minimally biased studies provides evidence for cancer risks from low-dose radiation. Here, we describe the framework for the systematic bias review and provide an overview of the eligible studies.
低剂量电离辐射是否会致癌是辐射防护中一个备受关注且存在长期争议的问题。自 2006 年美国国家科学院发布《电离辐射生物效应》报告以来，多项针对低剂量的大型、高影响力的流行病学研究发表了阳性剂量-反应关系的新结果。然而，有人认为这些发现可能存在偏差。我们对 2006 年至 2017 年间发表的、平均剂量小于 100mGy 的流行病学研究进行了系统综述。我们要求研究提供个体化剂量和置信区间内的剂量-反应估计值。我们共确定了 26 项符合条件的研究（8 项环境相关、4 项医学相关和 14 项职业相关），其中包括 91000 例实体癌和 13000 例白血病。平均剂量范围从 0.1 到 82mGy。在 22 项实体癌研究中有 16 项、在 20 项白血病研究中有 17 项显示出 100mGy 处的超额相对风险为阳性。本专论的目的是系统地审查这些研究中潜在的偏倚（包括剂量不确定性、混杂和结局错分），并评估在最小偏倚的研究中是否有证据表明低剂量辐射会导致癌症风险。在这里，我们描述了系统偏倚综述的框架，并提供了合格研究的概述。
