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Michael Siegel takes note of a new study [pdf] examining the effects of smoking bans on heart attacks. Published by RAND, the CBO, the University of Wisconsin, and Stanford, the study examines much larger data sets than previous research. I can’t access the full paper so I’m going off of Siegel’s summary. (If anyone has it, please send. Update: I have it now, thanks.) Here is what the authors find:

1. “In contrast with smaller regional studies, we find that workplace bans are not associated with statistically significant short-term declines in mortality or hospital admissions for myocardial infarction or other diseases.”

2. “An analysis simulating smaller studies using subsamples reveals that large short-term increases in myocardial infarction incidence following a workplace ban are as common as the large decreases reported in the published literature.”

Siegel puts this study’s methodological superiority into perspective:

To give you an idea of the scope of this study compared to previous ones, the Helena study involved a total of 304 heart attack admissions in one community over a period of six months. This study examined a total of 217,023 heart attack admissions and 2.0 million heart attack deaths in 468 counties in all 50 states over an eight-year period.

The authors on how publication bias favors pro-ban results:

We also show that there is wide year‐to‐year variation in myocardial infarction death and admission rates even in large regions such as counties and hospital catchment areas. Comparisons of small samples (which represent subsamples of our data and are similar to the samples used in the previous published literature) might have led to atypical findings. It is also possible that comparisons showing increases in cardiovascular events after a smoking ban were not submitted for publication because the results were considered implausible. Hence, the true distribution from single regions would include both increases and decreases in events and a mean close to zero, while the published record would show only decreases in events. Thus, publication bias could plausibly explain why dramatic short‐term public health improvements were seen in prior studies of smoking bans.

In January uncritical reporters breathlessly spread the news of a study in the small town of Pueblo, CO, that found a 40% reduction in heart attacks over three years following the imposition of a smoking ban. We can expect equally fervent coverage of this new study debunking that claim, right? Right?

I explained the myriad flaws in the Pueblo study in this post. So simple, even a New York Times reporter could understand it!

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