A combined analysis of North American case-control studies of residential radon and lung cancer
A combined analysis of North American case-control studies of residential radon and lung cancer
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DOI：
10.1080/15287390500260945
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发表时间：
2006-04-01
影响因子：
2.6
通讯作者：
Wilcox, HB
中科院分区：
文献类型：
--
作者：
Krewski, D;Lubin, JH;Wilcox, HB
队列研究一致表明，暴露于高水平氡的地下矿工患肺癌的风险过高，基于这些结果的推断表明，住宅氡可能是美国每年所有肺癌死亡人数的近10-75%。然而，住宅氡和肺癌的病例对照研究提供了氡肺癌风险的模糊证据。无论如何，来自短寿命放射性氡衰变产物的α粒子排放会破坏细胞DNA。一种已证实的肺癌致癌物可能存在于大量家庭中，这一可能性引起了严重的公共卫生问题。因此，对所有北美住宅氡研究的汇总数据进行了系统分析，以更直接地描述长期氡暴露造成的公共健康风险。为了评估与长期住宅氡气暴露相关的风险，对住宅氡气和肺癌风险的七项大规模病例对照研究的主要数据进行了综合分析。合并后的数据集共包括4081例病例和5281例对照，代表了迄今为止对住宅氡和肺癌数据的最大汇总。住宅氡浓度主要是由放置在生活区的研究对象的家，以获得一个综合的1年平均氡浓度在室内空气中的a-跟踪探测器。条件似然回归被用来估计由于住宅氡暴露的肺癌的超额风险，调整达到的年龄，性别，研究，吸烟因素，住宅的流动性，氡测量的完整性。虽然主要的分析是基于作为一个整体的组合数据集，我们也认为有更准确的氡剂量测定数据的子集。这包括一个数据子集，涉及3662例病例和4966例对照，在Krewski等人（2005年）之前考虑的索引日期之前5-30年的暴露时间窗（ETW）内进行a-轨道氡测量。额外的限制集中在受试者的ETW的更大比例所涵盖的测量，而不是估算的氡浓度，并在受试者谁占据了最多两个住宅。肺癌的估计比值比（OR）一般随氡浓度增加而增加。OR趋势与线性一致（p = 0.10），超额OR（EOR）为0.10/Bq/m（3），95%置信限（-0.01，0.26）。对于Krewski等人（2005）之前考虑的数据子集，EOR为0.11（0.00，0.28）。根据我们的标准（住宅稳定性和氡监测的完整性）进一步限制受试者，预计将改善氡剂量测定，导致EOR的估计增加。例如，对于在5-30 ETW中仅居住在一个或两个房屋中的受试者，并且在这25年期间至少有20年进行了α跟踪氡测量，EOR为0.18（0.02，0.43）每100 Bq/m（3）。这两个估计值都与通过向下外推矿工数据预测的每100 Bq/m（3）0.12（0.02，0.25）的EOR一致。总的来说，这些结果提供了直接的证据，住宅氡和肺癌的风险之间的关联，预测的结果从职业研究的氡暴露的地下矿工外推的结果。
Cohort studies have consistently shown underground miners exposed to high levels of radon to be at excess risk of lung cancer, and extrapolations based on those results indicate that residential radon may be responsible for nearly 10-75% of all lung cancer deaths per year in the United States. However, case-control studies of residential radon and lung cancer have provided ambiguous evidence of radon lung cancer risks. Regardless, alpha-particle emissions from the short-lived radioactive radon decay products can damage cellular DNA. The possibility that a demonstrated lung carcinogen may be present in large numbers of homes raises a serious public health concern. Thus, a systematic analysis of pooled data from all North American residential radon studies was undertaken to provide a more direct characterization of the public health risk posed by prolonged radon exposure. To evaluate the risk associated with prolonged residential radon exposure, a combined analysis of the primary data from seven large scale case-control studies of residential radon and lung cancer risk was conducted. The combined data set included a total of 4081 cases and 5281 controls, representing the largest aggregation of data on residential radon and lung cancer conducted to date. Residential radon concentrations were determined primarily by a-track detectors placed in the living areas of homes of the study subjects in order to obtain an integrated 1-yr average radon concentration in indoor air. Conditional likelihood regression was used to estimate the excess risk of lung cancer due to residential radon exposure, with adjustment for attained age, sex, study, smoking factors, residential mobility, and completeness of radon measurements. Although the main analyses were based on the combined data set as a whole, we also considered subsets of the data considered to have more accurate radon dosimetry. This included a subset of the data involving 3662 cases and 4966 controls with a-track radon measurements within the exposure time window (ETW) 5-30 yr prior to the index date considered previously by Krewski et al. (2005). Additional restrictions focused on subjects for which a greater proportion of the ETW was covered by measured rather than imputed radon concentrations, and on subjects who occupied at most two residences. The estimated odds ratio (OR) of lung cancer generally increased with radon concentration. The OR trend was consistent with linearity (p =.10), and the excess OR (EOR) was 0.10 per Bq/m(3) with 95% confidence limits (-0.01, 0.26). For the subset of the data considered previously by Krewski et al. (2005), the EOR was 0.11 (0.00, 0.28). Further limiting subjects based on our criteria (residential stability and completeness of radon monitoring) expected to improve radon dosimetry led to increased estimates of the EOR. For example, for subjects who had resided in only one or two houses in the 5-30 ETW and who had alpha-track radon measurements for at least 20 yr of this 25-yr period, the EOR was 0.18 (0.02, 0.43) per 100 Bq/m(3). Both estimates are compatible with the EOR of 0.12 (0.02, 0.25) per 100 Bq/m(3) predicted by downward extrapolation of the miner data. Collectively, these results provide direct evidence of an association between residential radon and lung cancer risk, a finding predicted by extrapolation of results from occupational studies of radon-exposed underground miners.