Ashmore J Patrick, Gentner Norman E, Osborne Richard V
Ponsonby & Associates, Manotick, ON, Canada.
J Radiol Prot. 2010 Jun;30(2):121-9. doi: 10.1088/0952-4746/30/2/001. Epub 2010 Jun 9.
In 1995 the International Agency for Research on Cancer (IARC) completed a study that involved nuclear workers from facilities in the USA, UK and Canada. The only significant, though weak, dose-related associations found were for leukaemia and multiple myeloma. The results for the Canadian cohort, which comprised workers from the facilities of Atomic Energy of Canada Limited (AECL), were compatible with those for the other national cohorts. In 2005, IARC completed a further study, involving nuclear workers from 15 countries, including Canada. In these results, the dose-related risk for leukaemia was not significant but the prominent finding was a statistically significant excess relative risk per sievert (ERR Sv(-1)) for 'all cancers excluding leukaemia'. Surprisingly, the risk ascribed to the Canadian cohort for all cancers excluding leukaemia, driven by the AECL sub-cohort, was significantly higher than the risk estimate for the 15-country cohort as a whole. We have attempted to identify why the results for the AECL cohort were so discrepant and had such a remarkable influence on the 15-country risk estimate. When considering the issues associated with data on the AECL cohorts and their handling, we noted a striking feature: a major change in outcome of studies that involved Canadian nuclear workers occurred concomitantly with the shift to when data from the National Dose Registry (NDR) of Canada were used directly rather than data from records at AECL. We concluded that an important contributor to the considerable upward shift in apparent risk in the 15-country and other Canadian studies that have been based on the NDR probably relates to pre-1971 data and, in particular, the absence from the NDR of the person-years of workers who had zero doses in the calendar years 1956 to 1970. Our recommendation was for there to be a comprehensive evaluation of the risks from radiation in nuclear industry workers in Canada, organisation by organisation, in which some of the anomalies that we have identified might be addressed.
1995年，国际癌症研究机构（IARC）完成了一项研究，该研究涉及来自美国、英国和加拿大核设施的工作人员。所发现的唯一显著（尽管较弱）的剂量相关关联是白血病和多发性骨髓瘤。加拿大队列（由加拿大原子能有限公司（AECL）设施的工作人员组成）的结果与其他国家队列的结果一致。2005年，IARC完成了另一项研究，涉及来自包括加拿大在内的15个国家的核工作人员。在这些结果中，白血病的剂量相关风险不显著，但突出的发现是“除白血病外的所有癌症”每西弗特的统计显著超额相对风险（ERR Sv(-1)）。令人惊讶的是，由AECL子队列驱动的加拿大队列中除白血病外所有癌症的风险显著高于15国队列整体的风险估计值。我们试图确定为什么AECL队列的结果如此不一致，以及对15国风险估计有如此显著的影响。在考虑与AECL队列数据及其处理相关的问题时，我们注意到一个显著特征：涉及加拿大核工作人员的研究结果的重大变化与从直接使用加拿大国家剂量登记处（NDR）的数据而非AECL记录的数据的转变同时发生。我们得出结论，在基于NDR的15国和其他加拿大研究中，明显风险大幅上升的一个重要因素可能与1971年前的数据有关，特别是NDR中缺少1956年至1970年日历年度零剂量工作人员的人年数。我们的建议是对加拿大核工业工人逐个组织地进行辐射风险的全面评估，其中我们所确定的一些异常情况可能会得到解决。
