As early as 2004, various medical journals published articles claiming that small-community smoking bans resulted in nearly immediate reductions in heart disease. For example, the high-profile BMJ reported that hospital admissions for acute myocardial infarction (AMI) declined 40%, from 40 to 24, in Helena, Montana, after implementation of a smoke-free ordinance (here). Circulation, the journal of the American Heart Association, reported that AMI admissions dropped 27% “within months” in Pueblo, Colorado (here). Similar reports came from Bowling Green, Ohio (here), Monroe County, Indiana (here) and beyond.
The striking implication was: Eliminating second-hand smoke saves lives by reducing heart disease.
There were two problems with these claims. First, the declines, based on small numbers of observations, were actually consistent with random variation (here). Second, none of the reports accounted for the long-term downward trend in heart disease in the U.S.; they credited no-smoking intervention with the lower number of AMIs at a time when rates were declining nationwide.
In 2011, I documented that state-wide smoking bans in California, Utah, Delaware, South Dakota, New York and Florida had little or no immediate measurable effect on AMI deaths. The study, published in the Journal of Community Health (here), eliminated the “tiny-number” problem and factored in the national downward trend in AMI deaths.
I discussed these findings in my blog (here), but the work was largely ignored, until now.
Recently, researchers from three Colorado institutions reported AMI rates before and after a statewide smoking ban there; their work appears in the American Journal of Medicine (here). (Thanks to Chris Snowdon, who also blogged about it here).
Paul Basel and colleagues found that “No signiﬁcant reduction in [AMI] rates was observed” after the Colorado ban was implemented. They also referred to our study:
“[The Rodu et al.] study compared the decline in [AMI] mortality in 6 states with smoke-free ordinances, with the average decline among 44 states unaffected by smoke-free policy. No state with a smoke-free ordinance had a signiﬁcantly lower observed [AMI] mortality compared with that expected by the nationwide secular decrease in states without the ordinance. This emerging evidence highlights the importance of accounting for secular trends in [AMI] incidence before deﬁnitive attribution to smoke-free ordinances can be made.”
It is comforting to see unfounded second-hand smoke claims corrected, particularly in the pages of a prestigious journal.