Further Information

Epidemiological Evidence on Environmental Tobacco Smoke and Breast Cancer. A Review with Meta-Analyses | P N Lee and J S Hamling
Article Published: 2008

Type: Meta-Analysis
Significance: Statistically Significant Positive

Published By: P.N. Lee

Further Information

If you believe that 2+2 does not make 4, if the truthful statement is made by a study financed by the tobacco industry, then do not examine this document.

On the other hand, if you think that mathematics are the same regardless of who pays the bills, you may be in for a voyage of discovery. The antismoking propaganda has associated passive smoking with over 100 “diseases.” The implication is that, by eliminating exposure to ETS, the incidence of those diseases would decrease. How dramatically? Given the flimsiness of the methodology used to gather the data in the first place – which defines quintessential junk science – that is only a function of your faith and beliefs.

Be that as it may, the conclusions of this meta-analysis are no surprise to those who put aside the ideology and look at the “science” as it is. In the citation below we have emphasized the critical words and provide links to other instrumental evidence in this portal.

“Results of 27 studies relating breast cancer in women to ETS exposure in nonsmokers have been published. This document presents a comprehensive review of the evidence, with meta-analysis.”


“Evidence of a dose-response relationship was similarly heterogeneous, with significant trends reported in a few studies contrasting with a complete lack of relationship reported in other studies.”

“There was no evidence of an association at all for childhood ETS exposure, and the increased relative risk estimate was not significant using indices based specifically on exposure from the spouse, in the workplace or from the spouse or other cohabitant. However it was notable that from those seven studies that provided estimates relating to total exposure, based on a detailed questionnaire that asked (at least) about at-home exposure in childhood and in adulthood and about workplace exposure, the relative risk estimate was quite high (1.41, 1.06-1.88).”

“Detailed examination of the evidence suggested that where associations were seen, the elevated risk estimate derived mainly from those case-control studies that asked very detailed questions about ETS exposure and depend heavily on the accuracy of the reported answers. Expressing estimates relative to a totally unexposed baseline produces estimates that are highly dependent on which subjects happen to get classified in the baseline group and may well be unusually subject to recall bias. Results from large prospective studies involving very detailed ETS exposure indices would aid interpretation, but to date are lacking.”

“Also relevant to interpretation of the data are weaknesses inherent in a number of studies and the possibilities of publication bias and uncontrolled confounding. Overall, in view of the inherent implausibility that ETS exposure might cause breast cancer, given the virtually identical risks in smokers and nonsmokers, and the doubts about the reliability of estimates from case-control studies involving extremely detailed questionnaires on ETS exposure, one cannot conclude that ETS exposure has actually been shown to increase the risk of breast cancer in nonsmokers.”

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