Goldsmith J R
Faculty of Health, Ben Gurion University of the Negev, Beer Sheva, Israel.
Health Phys. 1999 May;76(5):553-7. doi: 10.1097/00004032-199905000-00014.
There is little doubt that underground miners exposed to radon and its progeny have increased rates of lung cancer. Residential radon exposures should carry a possibly smaller risk of increased cancer. When it became possible to collect radon data in a large number of U.S. homes and the data were aggregated by counties, the apparent association with lung cancer was a negative one, even when many other variables were taken into account. Residential radon levels are higher in suburban residences leading to a negative association with population density. Population density is strongly positively associated with lung cancer. It follows that aggregate residential radon and lung cancer rates should be negatively associated for reasons having nothing to do with the possibility of radon being carcinogenic to the lung. A second problem presented by the data is the one of sampling bias since the county lung cancer data are from the whole county population, but only a few residences are tested. Examples of other inherent associations in environmental epidemiology are cited. One strategy is to study areas of the same population density but with radon exposure gradients. This is approximated by choice of rural high radon states. Counties in such states have weak and inconsistent associations between radon and lung cancer, some of which are positive. I conclude that counties are generally inappropriate units for study of radon and lung cancer associations.
毫无疑问，接触氡及其子体的地下矿工患肺癌的几率会增加。居住环境中的氡暴露可能会使患癌风险略有增加。当能够收集美国大量家庭的氡数据并按县进行汇总时，即便考虑了许多其他变量，氡与肺癌之间的明显关联仍是负相关。郊区住宅的室内氡水平较高，这导致与人口密度呈负相关。而人口密度与肺癌呈强烈正相关。由此可见，总体住宅氡水平与肺癌发病率应呈负相关，其原因与氡对肺部致癌的可能性毫无关系。这些数据呈现出的第二个问题是抽样偏差，因为县肺癌数据来自全县人口，但仅检测了少数住宅。文中列举了环境流行病学中其他内在关联的例子。一种策略是研究相同人口密度但存在氡暴露梯度的区域。选择农村高氡州可大致实现这一点。这些州的县中，氡与肺癌之间的关联微弱且不一致，其中一些呈正相关。我的结论是，县通常不是研究氡与肺癌关联的合适单位。
