INCONSISTENCY BETWEEN WORKPLACE AND SPOUSAL STUDIES OF ENVIRONMENTAL TOBACCO-SMOKE AND LUNG-CANCER

In a risk assessment released at the end of 1992, the U.S. Environment al Protection Agency (EPA) concluded that environmental tobacco smoke (ETS) is a known human lung carcinogen. The Agency reached that conclu sion primarily on the basis of epidemiologic studies of self-reported never-smoking women, in which the exposure index was marriage to a smo ker. However, the use of the spousal smoking exposure surrogate introd uces many potential confounding factors. Such confounding and bias due to denial of active smoking are likely explanations for weak and inco nsistent reported ETS-lung cancer associations. This contention is sup ported by the results of 14 worldwide studies of lung cancer and ETS e xposure in the workplace, which in combination indicated no risk eleva tion. Workplace ETS-lung cancer studies are not subject to the bias an d confounding introduced by the spousal smoking exposure surrogate. Th e EPA ignored the workplace studies in its risk assessment and extrapo lated the results of spousal smoking studies to workplace and other so urces 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 i n their entirety, the ETS-lung cancer epidemiologic data do not suppor t a causal inference or provide a scientific basis for government regu lation of smoking in the workplace. (C) 1994 Academic Press, Inc.