Lubin J H, Boice J D, Edling C, Hornung R W, Howe G R, Kunz E, Kusiak R A, Morrison H I, Radford E P, Samet J M
Epidemiology and Biostatistics Program, Division of Cancer Etiology, National Cancer Institute, Bethesda, Md 20892-7368, USA.
J Natl Cancer Inst. 1995 Jun 7;87(11):817-27. doi: 10.1093/jnci/87.11.817.
Radioactive radon is an inert gas that can migrate from soils and rocks and accumulate in enclosed areas, such as homes and underground mines. Studies of miners show that exposure to radon decay products causes lung cancer. Consequently, it is of public health interest to estimate accurately the consequences of daily, low-level exposure in homes to this known carcinogen. Epidemiologic studies of residential radon exposure are burdened by an inability to estimate exposure accurately, low total exposure, and subsequent small excess risks. As a result, the studies have been inconclusive to date. Estimates of the hazard posed by residential radon have been based on analyses of data on miners, with recent estimates based on a pooling of four occupational cohort studies of miners, including 360 lung cancer deaths.
To more fully describe the lung cancer risk in radon-exposed miners, we pooled original data from 11 studies of radon-exposed underground miners, conducted a comprehensive analysis, and developed models for estimating radon-associated lung cancer risk.
We pooled original data from 11 cohort studies of radon-exposed underground miners, including 65,000 men and more than 2700 lung cancer deaths, and fit various relative risk (RR) regression models.
The RR relationship for cumulative radon progeny exposure was consistently linear in the range of miner exposures, suggesting that exposures at lower levels, such as in homes, would carry some risk. The exposure-response trend for never-smokers was threefold the trend for smokers, indicating a greater RR for exposure in never-smokers. The RR from exposure diminished with time since the exposure occurred. For equal total exposure, exposures of long duration (and low rate) were more harmful than exposures of short duration (and high rate).
In the miners, about 40% of all lung cancer deaths may be due to radon progeny exposure, 70% of lung cancer deaths in never-smokers, and 39% of lung cancer deaths in smokers. In the United States, 10% of all lung cancer deaths might be due to indoor radon exposure, 11% of lung cancer deaths in smokers, and 30% of lung cancer deaths in never-smokers. This risk model estimates that reducing radon in all homes exceeding the U. S. Environmental Protection Agency's recommended action level may reduce lung cancer deaths about 2%-4%. These estimates should be interpreted with caution, because concomitant exposures of miners to agents such as arsenic or diesel exhaust may modify the radon effect and, when considered together with other differences between homes and mines, might reduce the generalizability of findings in miners.
放射性氡是一种惰性气体，可从土壤和岩石中逸出并积聚在封闭区域，如家庭和地下矿井。对矿工的研究表明，接触氡衰变产物会导致肺癌。因此，准确估计家庭中日常低水平接触这种已知致癌物的后果具有公共卫生意义。住宅氡暴露的流行病学研究因无法准确估计暴露量、总暴露量低以及随后的额外风险小而受到困扰。因此，迄今为止这些研究尚无定论。对住宅氡危害的估计一直基于对矿工数据的分析，最近的估计基于对四项矿工职业队列研究数据的汇总，其中包括360例肺癌死亡病例。
为了更全面地描述接触氡的矿工患肺癌的风险，我们汇总了11项接触氡的地下矿工研究的原始数据，进行了综合分析，并开发了估计与氡相关的肺癌风险的模型。
我们汇总了11项接触氡的地下矿工队列研究的原始数据，包括65000名男性和2700多例肺癌死亡病例，并拟合了各种相对风险（RR）回归模型。
在矿工接触氡的范围内，累积氡子体暴露的RR关系始终呈线性，这表明较低水平的暴露，如家庭中的暴露也会带来一定风险。从不吸烟者的暴露-反应趋势是吸烟者的三倍，这表明从不吸烟者接触氡的RR更高。暴露后的RR随时间推移而降低。对于总暴露量相同的情况，长时间（低暴露率）暴露比短时间（高暴露率）暴露危害更大。
在矿工中，所有肺癌死亡病例中约40%可能归因于氡子体暴露，从不吸烟者肺癌死亡病例的70%以及吸烟者肺癌死亡病例的39%归因于此。在美国，所有肺癌死亡病例中10%可能归因于室内氡暴露，吸烟者肺癌死亡病例的11%以及从不吸烟者肺癌死亡病例的30%归因于此。该风险模型估计，将所有超过美国环境保护局建议行动水平的家庭中的氡含量降低，可能会使肺癌死亡病例减少约2%-4%。这些估计应谨慎解读，因为矿工同时接触砷或柴油废气等物质可能会改变氡的影响，而且考虑到家庭和矿井之间的其他差异，矿工研究结果的普遍性可能会降低。
