体癌症风险的比率。在委员会 2000 年的报告中，这两种方法产生的结果大约相差 2 倍。但最近公布的关于地下矿工风险（从对许多铀矿工人群体的最新研究得出）的数据表明，这两种方法之间的差别并不像最初想象的那样大。不过，为了更好地了解和说明修正因素——如受照射以来的时间、已届年龄和剂量率的影响，以及混杂因素（特别是吸烟）所产生的影响，还需要开展更多的工作。45. 关于受到氡及其衰变产品照射的矿工的研究为评估这些矿工的癌症风险提供了一个直接基础。美国国家研究理事会氡照射的健康风险问题委员会《电离辐射的生物效应》系列研究报告第六份报告（BEIR VI）题为《氡照射的健康影响》，其中指出，累积照射低于 30 兆贝可小时每立方米（MBq h m-3）的矿工的氡照射超高相对风险相当于7每 MBq h m-3为 1.8%（95%置信区间：0.3, 35）。矿工照射评估中误差的产生有各种原因，特别是在照射量最高的开矿初期。造成矿工数据分析复杂化的其他因素有：抽烟的矿工百分比较高；工作场所受到尘土污染，如尘土中的砷、柴油废气和其他污染物；以及在非铀矿井中工作的时间长度。现在查明矿工中超高风险的能力可能非常小，这部分是因为照射剂量比采矿初期要小得多，另一部分是因为监测和记录保持的改善。由于采矿早期的照射剂量较高，因此有可能查明肺癌风险趋势和对影响剂量反应关系的各种因素进行调查，如受照年龄、剂量率的影响、风险随受照以来时间的增加而减少，以及吸烟等混杂因素的影响。
45. Studies of miners exposed to radon and its decay products provide a direct basis for assessing their lung cancer risk. The United States National Research Council’s Committee on Health Risks of Exposure to Radon in its sixth report in the study series Biological Effects of Ionizing Radiation (BEIR VI), entitled Health Effects of Exposure to Radon, reported an excess relative risk from exposure to radon that was equivalent7 to 1.8 per cent per megabecquerel hours per cubic metre (MBq h m-3) (95 per cent confidence interval: 0.3, 35) for miners with cumulative exposures below 30 MBq h m-3. There are various sources of error in the assessment of miners’ exposures, especially for the earliest years of mining when exposures were highest. Other factors that complicate the analyses of data on miners include the high percentage of miners who smoke; workplace exposure to dust contaminants, such as arsenic, diesel exhaust in the dust and other pollutants; and periods spent working in non-uranium mines. The power to detect any excess risks in miners nowadays is likely to be small, in part because the exposures are much smaller than in the early years of mining and in part because of improved monitoring and record-keeping. Because of the high exposures in the early days of mining, it is possible to detect trends in the risk of lung cancer and to investigate factors that affect the dose-response relationship, such as the age at exposure, the effect of dose rate and the reduction of risk with increasing time since exposure, as well as the effect of confounding factors such as smoking.