It was with some incredulity that I read the following in The Sunday Times.
THE ban on public smoking has caused a fall in heart attack rates of about 10%, a study has found.
Researchers commissioned by the Department of Health have found a far sharper fall than they had expected in the number of heart attacks in England in the year after the ban was imposed in July 2007.
In Scotland, where the ban was introduced a year earlier, heart attack rates have fallen by about 14% because of the ban, separate research has shown. Similar results are expected in Wales where a third study is still under way.
It is quite astonishing to see the 'Scottish heart miracle' make its way into the pages of The Times again, since they are well aware that the study did not reflect the true rate of hospital admissions.
Having reported the Dr Jill Pell's Scottish study in 2007 under the headline 'Non-smokers suffer fewer heart attacks after ban', the newspaper later included it as one of the Worst Junk Stats of 2007:
“Smoking ban cut heart attacks in Scotland by 17 per cent”, researchers and politicians trumpeted to the world in September through press releases, a conference and interviews, all faithfully reported.
It was the ban what done it, they said... until six weeks later when official data halved the drop — to 8 per cent — against a trend immediately before the ban of a 5 or 6 per cent drop, and a fall a few years ago of 11. All of which makes it hard to be sure what, if any, effect the ban really had. The researchers went strangely silent.
Harsh reality made things worse for Dr Pell and her Scottish miracle the following year when the full hospital data was published by the NHS. Anyone who has followed this story will be aware that the heart attack rate did not fall by anywhere near 14% (this is a new figure, by the way, previously it was always 17%) and that the rate rose in year 2 of the ban. This seemed to be the final nail in the coffin of the theory that smoking bans immediately slashed the heart attack rate, as I wrote in Sp!ked earlier this year:
The Scottish ‘miracle’ has ceased to be. It is no more. It has gone up to join the choir invisible. If Pell hadn’t nailed it to its perch, it would be pushing up the daisies.
It is extraordinary - truly extraordinary - that a newspaper that has already had its fingers burnt with these silly heart attack stories is so willing to do so again. This is all the more so since the study will not be published until next year and is, in the researchers' own words, "incomplete".
This is yet more - to use Michael Siegel's words - 'science by press release'. Dr Siegel has shown time and again that these heart attack studies are deeply flawed. The tricks used change from study to study but tricks they are. Not one of them can be considered to be serious science.
Will the English study be flawed? We can be sure of it if, as is claimed, it is going to make out that heart attacks fell by 10%. We know this because routine hospital data has (again) long-since been available. It shows no discernible difference in the heart attack rate before and after the smoking ban. This data was made available in February and I discussed it then. Dr Siegel showed English heart attack admissions in a graph (reproduced below), and wrote:
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.
The decline in heart attack admissions from 2006-2007 to 2007-2008 was 3.7%, compared to declines of 3.7% in the preceding year and 3.8% in the year before that.
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.
It will be fascinating to see how the authors of this new study manage to turn 2% into 10%, but we shall have to wait several months. When it is finally published, I suspect that The Times will have a strong contender for its Worst Junk Stats of 2010 list.
