LeVois M E, Layard M W
Environmental Health Resources, Tiburon, California 94920.
Regul Toxicol Pharmacol. 1994 Jun;19(3):309-16. doi: 10.1006/rtph.1994.1026.
In a risk assessment released at the end of 1992, the U.S. Environmental Protection Agency (EPA) concluded that environmental tobacco smoke (ETS) is a known human lung carcinogen. The Agency reached that conclusion primarily on the basis of epidemiologic studies of self-reported never-smoking women, in which the exposure index was marriage to a smoker. However, the use of the spousal smoking exposure surrogate introduces many potential confounding factors. Such confounding and bias due to denial of active smoking are likely explanations for weak and inconsistent reported ETS-lung cancer associations. This contention is supported by the results of 14 worldwide studies of lung cancer and ETS exposure in the workplace, which in combination indicated no risk elevation. Workplace ETS-lung cancer studies are not subject to the bias and confounding introduced by the spousal smoking exposure surrogate. The EPA ignored the workplace studies in its risk assessment and extrapolated the results of spousal smoking studies to workplace and other sources of ETS exposure. In its estimate of ETS-attributable lung cancer deaths in the United States, the EPA ascribed over 70% of the deaths to nonspousal ETS exposure, primarily workplace exposure. Considered in their entirety, the ETS-lung cancer epidemiologic data do not support a causal inference or provide a scientific basis for government regulation of smoking in the workplace.
在1992年末发布的一份风险评估报告中，美国环境保护局（EPA）得出结论，环境烟草烟雾（ETS）是一种已知的人类肺癌致癌物。该机构得出这一结论主要基于对自我报告从不吸烟女性的流行病学研究，其中暴露指数是与吸烟者结婚。然而，使用配偶吸烟暴露替代指标引入了许多潜在的混杂因素。这种因否认主动吸烟导致的混杂和偏差很可能是所报告的ETS与肺癌之间关联微弱且不一致的原因。这一观点得到了14项全球范围内关于工作场所肺癌与ETS暴露研究结果的支持，这些研究综合起来表明不存在风险升高。工作场所ETS与肺癌的研究不存在因配偶吸烟暴露替代指标所引入的偏差和混杂。EPA在其风险评估中忽略了工作场所研究，并将配偶吸烟研究的结果外推至工作场所及其他ETS暴露源。在对美国ETS导致的肺癌死亡人数估计中，EPA将超过70%的死亡归因于非配偶ETS暴露，主要是工作场所暴露。从整体来看，ETS与肺癌的流行病学数据不支持因果推断，也未为政府对工作场所吸烟进行监管提供科学依据。
