On Reason Magazine's Hit & Run blog, Jacob Sullum explains my opinion about the recently-released Massachusetts smoking ban/heart disease mortality study better than I have yet articulated it.
First, he notes that the study does not support a conclusion that smoking bans lead to an immediate (within one year) reduction in heart attacks, as was reported by studies in Helena, Pueblo, Bowling Green, and elsewhere.
The rate of heart attack deaths was declining prior to the statewide ban, and after the ban, continued to decline - even more sharply. But this acceleration of the decline took place both in communities that were and were not already subject to a smoking ban, which is not what one would have expected if the statewide ban were the explanation for the accelerated decline.
Moreover, the study provides no evidence that secondhand smoke exposure is a trigger for heart attacks and that any significant, immediate decline in heart attacks occurred as a result of reduced secondhand smoke exposure, as is claimed by many anti-smoking groups and advocates.
What Sullum does note is that smoking bans can be expected to reduce heart disease incidence over the long term because of reductions in smoking.
From his column: "Siegel adds that cities with smoking bans did see significant reductions in heart attack deaths compared to cities without such laws in the seven-year period from 1999 through 2006. They also had lower smoking rates, which suggests they may be seeing the results of improving health in former smokers who quit as a result of the ordinances."
"Case-control studies indicate that the heart disease rate among former smokers falls by about 50 percent within four years of quitting. In short, even if secondhand smoke has no measurable impact on death rates, over the long term smoking bans can be expected to reduce the incidence of heart disease (and other smoking-related illnesses) by pressuring smokers to quit. From a "public health" perspective, in fact, that is the main benefit of smoking bans. But whether we're talking about smokers or nonsmokers, immediate, sharp reductions (within the first six months to a year) are not biologically plausible, and they're not what the Massachusetts study found."
The Rest of the Story
I hope that my position on this study is now clear. While I believe that it does provide evidence that smoking bans - due to the associated decline in smoking prevalence caused by the pressure on smokers to quit - will have a long-term effect on reducing heart disease incidence, I do not believe that the study supports either the conclusion that smoking bans lead to an immediate reduction in heart attacks or the conclusion that brief secondhand smoke exposure is causing people to keel over from heart attacks who would not otherwise have these heart attacks.