Alex Massie Alex Massie

Smoking Bans = Fewer Heart Attacks? Up To A Point, Lord Copper

Oh my, what a credulous press corps we have. Selectively credulous that is. Put it this way: if a report compiled by a Philip Morris board member suggested smoking was good for you it wouldn’t be taken terribly seriously. But let an ASH board member – in this case Dr Anna Gilmore – put together a report that says the smoking ban in England & Wales “caused” a “dramatic” fall in heart attacks and the newspapers will be happy to be spoon-fed their reporting.

Now, you may say that the existence of the report is itself news. Perhaps so. But, again, the provenance of the report matters too and should be borne in mind. But no: the BBC, the Times, the Telegraph, the Independent and the Daily Mail all swallow the party line with only the BBC daring to even include a solitary dissenting voice tacked on to the end of their article.

So has there been a fall in heart attacks? Yes. Does this have anything to do with the smoking ban? That’s harder to say. Let’s have a look at a chart:

The actual numbers:

2002/03: 61,498, 2003/04: 60,680 (a fall of 1.33%), 2004/05: 58,803 (a fall of 3.1%), 2005/06: 55,752 (a fall of 5.19%), 2006/07: 53,964 (a fall of 3.21%), 2007/08: 51,664 (a fall of 4.26%)

So the trend was already downwards and has not, in fact, been accelerated by the smoking ban. That’s what the report’s own numbers seem to say. I pinched this chart from Chris Snowden and here’s what he has to say:

From this almost incomprehensible mass of heavily adjusted data, she [Gilmore] arrives at the figure of 2.4% mentioned above. This 2.4% is the supposed decline in AMI admissions that she directly attributes to the smoking ban. Since the total decline was only 4.26%, this means that the smoking ban was responsible for more than half of the drop; hence the newsworthy but entirely spurious ‘smoking ban prevents 1,200 heart attacks’ claim.    Although the AMI rate had fallen by 3.21% and 5.19% in 2005/06 and 2006/07, we are expected to believe the decline would only have been 1.86% in 2007/08 if the smoking ban had never happened.    In short, we are expected to believe that there was going to be a smaller than average decline in AMI in 2007/08, and that the smoking ban saved the day. The fact that the decline in AMI was unexceptional in 2007/08 is therefore used as proof that the smoking ban had an exceptional effect!    This is fairy-tale science. It is sheer statistical manipulation and it is breath-taking in it scope and ambition. But then, as I have said before, it always had to be.

This seems persuasive to me but then I am open to being persuaded by it.

Even so, you might think that the rest of the national press might pause to wonder if the stuff they’re fed by ASH – or the Department of Health for that matter – is any less impartial or flawed as anything that they might be handed by British American Tobacco. That doesn’t mean it is wrong since, presumably, the data may be interpreted in different ways, not that there’s anything improper about the report. Merely that there would seem to be legitimate grounds upon which to question it. Then again, I’m no kind of statistician so may be completely wrong.

As always I recommend Snowden’s  blog for all your smoking-related needs. Ditto his excellent history of anti-smoking, Velvet Glove, Iron Fist.

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