New Study Purports to Show 10% Decline in Heart Attacks in England Due to Smoking Ban; However, It is Just Another Example of Science by Press Release

As reported widely by newspapers in the UK in the past few days, a new study has purportedly found that in the year following the smoking ban which was implemented in England in July 2007, heart attacks fell by 10%, an effect the researchers conclude is due to the smoking ban (Times Online story; Yahoo! story; Telegraph story; Mail Online story).

According to the Mail Online article: "The ban on smoking in public has led to a dramatic fall in heart attack rates, it was claimed today. Researchers say the number of heart attacks in England plummeted by 10 per cent in the year after the ban was imposed in July 2007. A similar drop was also recorded in Scotland where another study discovered a 14 per cent decrease in the year after the ban was introduced there. A third study is currently underway in Wales."

"The latest figures - compiled for the Department of Health - will inevitably increase the pressure on the government to widen the ban to other areas. Ministers have already commissioned a study into the possibility of banning smoking in all cars. And there are now calls from anti-smoking groups for parents to be banned from smoking in front of their children at home." ...

"Anna Gilmore, from Bath University, is leading the research into heart attack rates in England. She said: 'There is already overwhelming evidence that reducing people's exposure to cigarette smoke reduces hospital admissions due to heart attacks.' The final results for England, however, will not be published until next year."

The Rest of the Story

It turns out that there is no "study" to behold. The "study" appears to merely be a work in progress that has not yet been published or even submitted for publication, yet its results and conclusion were widely disseminated through the media. In other words, this is yet another example of what I call "science by press release."

It appears that the conclusions of the study have been released to the media, but that the actual research itself is not being made publicly available. The study itself is not available, from what I can tell, on the University of Bath web site or the web site of the UK Centre for Tobacco Control Studies.

Therefore, it is impossible to judge whether the conclusions of the study are valid or not. And if the conclusions turn out to be unwarranted, then it will be too late to reverse them. The media have already disseminated the conclusion widely. Any correction given down the road would have little effect.

In most cases, I believe the results of a scientific study should not be released to the media prior to publication. However, if the results of a study are going to be released to the media at this conference, then I believe it is imperative that the study itself be made available for public scrutiny. You can't just release the conclusions, but not the study itself.

Moreover, if the manuscript is going to be submitted for publication, then it may be inappropriate to release the findings to the media prior to publication. Many journals have explicit policies that preclude the authors of submitted manuscripts from releasing the results to the media until publication.

It is problematic that the study authors have apparently released their results and conclusions to the media but that they have not released the full results and methods of the study because without the full methods and results, it is not possible for others in the field to adequately review the work and assess its validity. I personally feel that researchers should not publicize study findings through the media prior to publication unless they are willing to make the full findings and methods available. Releasing results via press release to the media should not be done until publication, or if it needs to be done before publication, then it should only be done with concomitant release of the entire study.

When the study is finally released, it will be very interesting to see how the researchers came up with the finding of a 10% decline in heart attacks in England during the first year following the ban. According to Christopher Snowdon at Velvet Glove Iron Fist, National Health Service statistics show that there was only a 2% decline in heart attack admissions in England from 2006-07 to 2007-08, compared to a 2.8% decline in the preceding year and a 3.8% decline in the year preceding that. Thus, these data show no evidence that the smoking ban resulted in any significant, immediate decline in heart attacks.

Furthermore, if you graph the trends in heart attacks in England using the NHS data, you will see no apparent change in the small but steady decline in heart attack admissions that has been observed since 2002.

In 2007-2008, there were 54,759 emergency room heart attack admissions in England. During the preceding year (2006-2007), there were 56,889 admissions. This is a decline of 3.7%.

What was the decline in heart attack admissions in England during the prior year? Also 3.7%. And the year before that? 3.8%.

As one can see visually, there is absolutely no change in the trend of declining heart attack admissions in England during the first nine months during which the ban was in effect. There appears to be a relatively steady decline in heart attack admissions from 2002-2008, with no change associated with the smoking ban.

Thus, this analysis confirms that no matter how you look at it, there was no change in the rate of declines in heart attack admissions in England associated with the first nine months of the smoking ban.

Given these findings from the national data, it will be very interesting to see how the researchers have come up with the finding of a 10% decline in heart attacks during roughly the same time period.

Unfortunately, because this is science by press release, we have no idea of how the researchers came up with their 10% figure, what methods they used, what data this figure is based on, and whether there is any validity to their conclusion that the observed decline in heart attacks is attributable to the smoking ban, rather than to the established secular trend of declining heart attacks over the past seven years in England.

What strikes me as particularly odd is that so many of these examples of science by press release are coming in a single area of research: the effects of smoking bans on heart attacks. For some reason, anti-smoking researchers in this area of inquiry have largely abandoned the usual scientific approach and instead have adopted the science by press release tactic. Why is this?

Perhaps the clue comes in the second part of the Mail Online article I cited above, where it reports that these new data are going to be used to pressure government officials to ban smoking in private cars and homes where children are present. It appears that many anti-smoking groups and advocates believe that these conclusions are needed to put pressure on government officials to ban smoking in cars and homes, apparently the next item on the anti-smoking agenda. But rather than wait until rigorous, peer-reviewed studies have been conducted to determine the impact of smoking bans on heart attacks, advocates are using science by press release to disseminate premature conclusions that will most likely not be borne out by subsequent scientific scrutiny.

Of course, it will be too late once the truth comes out, because these policies will already have been enacted on the basis of the premature conclusions that were disseminated by press releases, rather than by scientific journals.

I guess that's exactly the point, but it's really sad for me to see. The scientific integrity of the tobacco control movement is imploding before my very eyes.