A few weeks ago, I noted a study of 74 U.S. cities with smoking bans that contradicted the widely repeated claim that such laws lead to immediate, dramatic reductions in heart attacks. A study recently reported in the Journal of Community Health likewise finds no such changes in six states with smoking bans:

Target-year declines in AMI [acute myocardial infarction] mortality in California (2.0%), Utah (7.7%) and Delaware (8.1%) were not significantly different from the expected declines (P = 0.16, 0.43 and 0.89, respectively). In South Dakota AMI mortality increased 8.9% in the target year (P = 0.007). Both a 9% decline in Florida and a 12% decline in New York in the 2004 target year exceeded the expected declines (P = 0.04 and P < 0.0002, respectively) but were not significantly different (P = 0.55 and 0.08, respectively) from the 9.8% decline that year in the 44 states without bans. Smoke-free ordinances provide a healthy indoor environment, but their implementation in six states had little or no immediate measurable effect on AMI mortality.

Similarly, notes tobacco policy blogger Michael Siegel, data from Ohio, where a statewide smoking ban took effect in 2007, show the following declines in hospital discharges for myocardial infarction:

2005-2006 (baseline): -4.7% 

2006-2007 (first year of implementation): -2.7% 

2007-2008 (second year of implementation): -2.2% 

2008-2009 (third year of implementation): -6.3% 

Average annual decline post-implementation: -3.6%

In other words, Siegel writes, "the rate of decline in heart attack discharges in Ohio was greater prior to the smoking ban than it was in the first three years after the smoking ban," which "clearly does not support the conclusion that the smoking ban resulted in a large and immediate decline in heart attack discharges." The Ohio Department of Health nevertheless concludes (PDF) that there was "a sharp decline in heart attack rates immediately following implementation of the law." In fact, it says, there was "a significant change in age‐adjusted rates of AMI discharges within one month [!] after the enactment of the Smoke‐Free Workplace Act." Siegel (who supports smoking bans but opposes unscientific arguments in favor of them) analyzes the statistical trickery behind those conclusions here and here.

The data from these seven states fit the pattern Siegel has noted: While a few small jurisdictions, such as Helena, Montana, and Pueblo, Colorado, have seen big drops in AMI rates after implementing their smoking bans, studies that look at multiple jurisdictions and bigger populations (including analyses of nationwide data) find no such effect. Ban boosters focus on the few places that fit the story they want to tell, ignoring the broader picture. This blatant cherry picking has been blessed by the National Academy of Sciences, whose Institute of Medicine issued a 2009 report endorsing the biologically implausible notion that smoking bans have a noticeable impact on heart attack rates within a year or two. In light of the accumulating evidence to the contrary (much of which was available when the report was written), that embarrassing conclusion should be revisited.