- Hit & Run : Reason Magazine
Jump to full article: Reason Magazine, 2009-10-16
Author: Jacob Sullum
Intro: Just kidding. The report, which an Institute of Medicine committee issued yesterday, concludes, per the press release, that "smoking bans reduce the risk of heart attacks associated with secondhand smoke." The committee's chairwoman, Lynn Goldman, a professor of environmental health sciences at Johns Hopkins, sums up the report's findings this way:
It's clear that smoking bans work. . . .
As with the 2006 surgeon general's report on secondhand smoke, the press release goes farther than the report itself, which in turn draws conclusions that are not justified by the evidence it presents. The judgment about the effectiveness of smoking bans is based on 11 studies that looked at heart attack rates in eight jurisdictions after smoking bans took effect. "None was designed to test the hypothesis that secondhand-smoke exposure causes cardiovascular disease or acute coronary events," the report concedes. Furthermore, "only two of the studies distinguished between reductions in heart attacks suffered by smokers versus nonsmokers." Even so, the report concludes that smoking bans reduce heart attacks, at least partly by reducing nonsmokers' exposure to secondhand smoke.
To accomplish that impressive feat, the report underplays two major problems with attempts to measure the impact of smoking bans through observational studies. First, in recent decades there has been a general decline in heart attack rates, driven mainly by improvements in preventive medication and treatment. A decrease in heart attacks seen after a smoking ban takes effect could be part of this pre-existing trend. . . .
Second, random variation means that some jurisdictions with smoking bans are bound to see significant drops in heart attacks purely by chance, while others will see no real change or significant increases. . . .
That study, published by the National Bureau of Economic Research in March, suggests that publication bias can explain what the IOM panel describes as the "consistent" results of the studies it considered . . .
The NBER paper was mysteriously excluded from the IOM report, even though the authors say they bent over backward to compensate for publication bias by looking for relevant data that did not appear in medical journals. They also ignored analyses that found no declines in heart attacks following smoking bans in California, Florida, New York, Oregon, England, Wales, and Scotland. . . .
The report is slippery in addressing the biological plausibility of attributing immediate, dramatic reductions in heart attacks to smoking bans. . . .
Although the authors work hard to make patently ridiculous claims seem plausible, they never settle on an explanation of how, exactly, these reductions in heart attacks are accomplished. . . .
Assuming that smoking bans do reduce heart attacks, that result could be due to declines in smoking, declines in secondhand smoke exposure, or some combination of the two. The report settles on that last explanation, even though only two of the 11 studies bothered to distinguish between smokers and nonsmokers. . . .
The main goal of this project, which was commissioned by the CDC, seems to have been producing a document that could be waved around at city council meetings and state legislative hearings. If so, the authors have succeeded. . . .
My own view is that the scientific findings are not relevant to the policy question, which is a matter of property rights. . . .
Yet the people conducting these reviews are not neutral observers either; as reflected by Benowitz's comments, they are committed partisans in the push to extend strict smoking bans across the country.
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