Wednesday, November 25, 2009

Study that Reported a 27% Decline in Heart Attacks in Starkville Due to Smoking Ban Wasn't Actually a Study; Analysis Hasn't Yet Been Conducted

On November 10, I reported on a press release issued by Mississippi State University which claimed that a new study demonstrated that a local smoking ban in Starkville resulted in a 27% decline in heart attacks.

According to the press release: "A Mississippi State study released Monday [Nov. 9] shows a 27 percent decrease in heart attacks among Starkville residents since the city passed a smoking ban in 2006. Researchers associated with the university report also are recommending a statewide public ban on smoking. The study by Robert McMillen and Dr. Robert Collins shows fewer heart attacks being treated at the Oktibbeha County Hospital. It focused on Starkville residents in the three-year span after the ban became law, compared to three years prior."

The Starkville smoking ban went into effect in May 2006. The researchers found that the rate of heart attack admissions among Starkville residents at the Oktibbeha County Hospital decreased by 27% from the three -year period proceeding the ban (2003 through 2005) to the three-year period following the ban (2006 through 2008). They attribute this decline to the smoking ban.

The conclusions in the press release were widely disseminated through the media (example 1; example 2; example 3; example 4). Headlines boasted that: "Study Links Decline in Heart Attacks to Smoking Bans."

A summary of the study appeared on the internet, but the actual study itself did not (at least I could not find it).

One of the study authors was quoted in the Starkville Daily News as quantifying the precise effect of the smoking ban on reduced heart attacks: "We have saved $750,000." This calculation assumes that all of the 27% decline in heart attacks during the period 2006-2008 was attributable to the smoking ban.

The Rest of the Story

As it turns out, it appears that there was no study. These were simply preliminary data on hospital admissions in one community. There is a study ongoing in which acute myocardial infarction (heart attack) rates will be compared between communities with and without smoking bans, but those data have not yet been collected.

Jacob Grier over at Coffee, Cocktails, and Commentary has discovered, through a communication with one of the authors of the so-called study, that there is no study written up. There is only the 2-page summary, which explains why my attempt to locate the study on the internet was futile.

According to Grier, when he asked the "study" authors for a copy of the actual study, all he received was an email from one of the study authors which stated:

"The results that we released in our 2 page report are preliminary results from a larger study. The study examine[s] AMI admissions from several communities that have passed smoke-free ordinances, as well as communities that have not. The latter will serve as controls for the purpose of comparison. The hospital in Starkville was the first to provide us with AMI admission data. When we have received data from the other communities in our study we will prepare a manuscript that compares AMI admissions before and after the smoke-free laws were enacted in communities with and without smoke-free laws."

In other words, the study has not yet been conducted!

As the author admits, the study consists of the following methodology: compare trends in heart attack rates between communities with and without smoking bans. That is an appropriate methodology, as it will control for secular changes that are occurring in heart attack rates.

Well, if the study has not yet been conducted, then how can the "authors" issue a press release with the study's conclusion?

If ever there was an example of researchers coming to a pre-determined conclusion about their research hypothesis, this is it.

Anti-smoking researchers are apparently so eager to communicate favorable findings to the public that they can't even wait to conduct their studies any more. In this case, data from the intervention group was obtained and immediately released, before the data from the control communities could be examined for comparison purposes.

As Grier correctly points out, the 27% decline in heart attacks in Starkville doesn't mean anything in the absence of knowledge of what happened in communities without smoking bans. If there were also large declines in heart attacks in those localities, then the observed decline in Starkville was not attributable to the smoking ban.

Fortunately, the researchers appear to be aware that they cannot draw such a conclusion without having a comparison group. This is presumably why they are collecting data from a number of communities that did and did not implement smoking bans.

However, the researchers did draw such a causal conclusion and they disseminated it widely through a press release. Moreover, they attributed the entire 27% reduction in heart attacks to the smoking ban, and went as far as calculating the cost savings associated with the reduction in heart attacks, concluding that the smoking ban resulted in a $750,000 savings.

What exactly is the point of doing the study at this point? The conclusion has already been widely disseminated. If the study is done and the conclusion turns out to have been wrong, are the investigators going to frantically issue press releases urging newspapers to blast headlines on their front pages saying "Never Mind"?

It's too late. The conclusion has already been communicated to the public. Anti-smoking groups are already disseminated the results of this "study" themselves and touting it as evidence that smoking bans produce immediate reductions in heart attacks.

Although I am myself a strong anti-smoking advocate who supports smoking bans, I have to agree with Jacob Grier when he concludes that: "to go public with results now, before the data is even collected, is a corruption of science for the pursuit of political ends and unfortunately all too typical for today's anti-smoking movement."

There is a great deal of bias apparent in these smoking ban/heart attack studies. Perhaps that's why the objective data from all the large population-based analyses do not support the conclusions from the individual studies conducted in small communities. The Institute of Medicine committee wasn't even interested in examining the data from these population-based analyses.

The rest of the story is that the anti-smoking researchers down in Mississippi have already come to a pre-determined conclusion about the effects of smoking bans on heart attacks. The study itself is not needed. This is why it's apparently viewed as reasonable to disseminate the conclusions before the study has been conducted. This loss of scientific integrity is becoming all too common in the tobacco control movement these days.

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