Writing in the Washington Post, Gio Batta Gori, a former deputy director of the National Cancer Institute's Division of Cancer Cause and Prevention, addresses the Surgeon General report that has helped fuel many a smoking ban:
- Last July, introducing his office's latest report on secondhand smoke, then-U.S. Surgeon General Richard Carmona asserted that "there is no risk-free level of secondhand smoke exposure," that "breathing secondhand smoke for even a short time can damage cells and set the cancer process in motion," and that children exposed to secondhand smoke will "eventually . . . develop cardiovascular disease and cancers over time."
The report was a meta-analysis, and here's how the studies from which it draws were conducted:
- Typically, the studies asked 60--70 year-old self-declared nonsmokers to recall how many cigarettes, cigars or pipes might have been smoked in their presence during their lifetimes, how thick the smoke might have been in the rooms, whether the windows were open, and similar vagaries. Obtained mostly during brief phone interviews, answers were then recorded as precise measures of lifetime individual exposures.
In reality, it is impossible to summarize accurately from momentary and vague recalls, and with an absurd expectation of precision, the total exposure to secondhand smoke over more than a half-century of a person's lifetime. No measure of cumulative lifetime secondhand smoke exposure was ever possible, so the epidemiologic studies estimated risk based not only on an improper marker of exposure, but also on exposure data that are illusory.
In addition, results are not consistently reproducible. The majority of studies do not report a statistically significant change in risk from secondhand smoke exposure, some studies show an increase in risk, and–astoundingly--some show a reduction of risk.
Some prominent anti-smokers have been quietly forthcoming on what "the science" does and does not show. Asked to quantify secondhand smoke risks at a 2006 hearing at the UK House of Lords, Oxford epidemiologist Sir Richard Peto--a leader of the secondhand smoke crusade--replied, "I am sorry not to be more helpful; you want numbers and I could give you numbers..., but what does one make of them? ...These hazards cannot be directly measured."
This Regulation piece by Thomas Lambert also delves into the SG's report, pointing out some discrepancies between the press release (which claims "even brief expose to secondhand smoke has immediate adverse effects") and the report itself (which considers only long-term exposure).
The SG's report also omits a 2003 study published in the British Journal of Medicine which used 39-years-worth of data collected on 35,000 never-smokers married to smokers. The conclusion: there was "no causal relationship between exposure to [Environmental Tobacco Smoke] and tobacco-related mortality."
Now let's step up the crackdown on dihydrogen monoxide!