International Academy of Hi-Tech Services, Inc.
Dose Response. 2012;10(3):415-61. doi: 10.2203/dose-response.09-059.Leonard. Epub 2010 Sep 10.
Since the publication of the BEIR VI (1999) report on health risks from radon, a significant amount of new data has been published showing various mechanisms that may affect the ultimate assessment of radon as a carcinogen, in particular the potentially deleterious Bystander Effect (BE) and the potentially beneficial Adaptive Response radio-protection (AR). The case-control radon lung cancer risk data of the pooled 13 European countries radon study (Darby et al 2005, 2006) and the 8 North American pooled study (Krewski et al 2005, 2006) have been evaluated. The large variation in the odds ratios of lung cancer from radon risk is reconciled, based on the large variation in geological and ecological conditions and variation in the degree of adaptive response radio-protection against the bystander effect induced lung damage. The analysis clearly shows Bystander Effect radon lung cancer induction and Adaptive Response reduction in lung cancer in some geographical regions. It is estimated that for radon levels up to about 400 Bq m(-3) there is about a 30% probability that no human lung cancer risk from radon will be experienced and a 20% probability that the risk is below the zero-radon, endogenic spontaneous or perhaps even genetically inheritable lung cancer risk rate. The BEIR VI (1999) and EPA (2003) estimates of human lung cancer deaths from radon are most likely significantly excessive. The assumption of linearity of risk, by the Linear No-Threshold Model, with increasing radon exposure is invalid.
自 1999 年 BEIR VI（第六次报告）发布以来，大量新数据表明，各种机制可能会影响对氡作为致癌物的最终评估，特别是潜在的有害旁观者效应（Bystander Effect，BE）和潜在有益的适应性反应防护（Adaptive Response radio-protection，AR）。对 pooled 13 个欧洲国家氡研究（Darby 等人，2005 年，2006 年）和 8 个北美 pooled 研究（Krewski 等人，2005 年，2006 年）的病例对照氡肺癌风险数据进行了评估。根据地质和生态条件的巨大差异以及对旁观者效应诱导的肺损伤的适应性反应防护程度的差异，调和了来自氡风险的肺癌比值比的巨大差异。分析清楚地表明，在某些地理区域存在旁观者效应氡肺癌诱导和适应性反应降低肺癌的情况。据估计，对于氡水平高达约 400 Bq m(-3)，大约有 30%的可能性不会因氡而导致人类肺癌风险，20%的可能性是风险低于零氡、内源性自发或可能甚至遗传可继承的肺癌风险率。BEIR VI（1999 年）和 EPA（2003 年）对人类因氡导致的肺癌死亡的估计很可能过高。线性无阈值模型（Linear No-Threshold Model）假设风险随氡暴露的增加而呈线性，这种假设是无效的。
