Friday, 23 October 2009

No heart miracle in any Australian state


Yesterday I discussed Australia's hospital admissions data which show that a series of smoking bans have done nothing to reduce that nation's heart attack rate. Far from resulting in a 40% fall - as claimed by the infamous Helena study - rates of acute myocardial infarction have continued to rise. 

Since each Australian state acted independently, it is useful to look at them individually. The graphs below show rates of heart attack admissions in Australian public hospitals between 2000 and 2008. The date of the smoking ban is shown with an arrow in each case.

Of most interest is the data from Western Australia, Tasmania and Queensland. These three states were the first to introduce comprehensive smoking bans (in January 2005, January 2006 and July 2006 respectively) and so have the longest follow-up time in which a fall in heart attack incidence could manifest itself. As you can see from the graphs below, that did not happen.


Western Australia



Tasmania



Queensland


In every case, heart attack admissions rose over time and there was no positive effect from each state's smoking ban. If one adopted the post hoc ergo proptor hoc rationale of Stanton Glantz and the other "smoking bans slash heart attacks" advocates, one might even say that the smoking bans of Western Australia and Queensland resulted in even more lives being lost. This would be abject nonsense, but no more so than the conclusions of studies from out-of-the-way places like Helena, Pueblo and Bowling Green (which, incidentally, have far fewer people living in them).

Hospital admissions statistics from the other Australian regions follow much the same pattern. Again, there is a long-term rise and, again, the introduction of smoking bans had no discernible effect on the year-on-year fluctuations that are inevitable in such data. In fact, if one were feeling uncharitable, it would (again) be technically true to say that 3 of these 4 regions saw the heart attack rate rise more sharply after the ban than before it. Of all the Australian states, only South Australia saw a fall in the rate, albeit by only 1.5%.


Australian Capital Territory



New South Wales



Victoria




South Australia




These figures, I think, speak for themselves. The arrows might as well have been placed there in a game of pin the tail on the donkey for all the relevance they have to the number of people suffering heart attacks. There is no correlation whatsoever. In this respect they are entirely in keeping with the data from England, Scotland and Wales

It is not inconceivable that in the next few months we shall see some researcher come forth clutching a study showing that heart attacks fell by 30 or 40 per cent in Eucla or Katoomba or God knows where after the smoking ban. It is even conceivable that news of this miracle would sweep around the world like the notorious Helena and Scotland studies did. 

It would, however, be nice to think that journalists might ask themselves whether data collected by professional tobacco control advocates from obscure towns really trumps genuine hospital admissions data collected by professional statisticians from entire nations.

But that, I fear, may be too much to hope for.

[All figures come from the Australian government's 'Australian hospital statistics' series]



12 comments:

helend498 said...

Brilliantly explained as always Chris!

I too fear that journalists will ignore this and continue to pluck the figures from obscure towns that suit their agenda.

Blueblackjack said...

*Applaud*

The witch from Essex said...

These heart attack rises are probably the result of stress at not being able to smoke comfortably in a relaxing bar.

Frank Davis said...

It's been my general understanding that heart attacks have been on the decline for several decades, and that this is is main reason why heart attacks in the UK and USA show declines after smoking bans. They are just continuations of existing trends.

So I'm a bit surprised that Australian heart attacks are increasing rather than decreasing - although not surprised that smoking bans have no effect on this trend.

I'm now wondering that my vague notion that heart attacks peaked sometime in the late 20th century and have been declining ever since is either mistaken or only partly true. What is your general understanding?

Fredrik Eich said...

Nice one Mr Snowdon!
Looking at these graphs upside down and side by side, one could be forgiven for thinking that staggered post ban trend breaks do start to appear. In fact I would think that they would be in the media every where - IF they were the other way round(phantom trend breaks or not!).
I am most likely in a world wide minority of one with my take on the subject but it will be interesting to look at these numbers as time goes on.
Frank, is it this chart your thinking of?

Snowdon said...

Good question Frank. Part of the reason is a change in diagnosis, I think. The vast majority of the rise comes from acute subendocardial myocardial infarction (I21.4), which rose from 5,813 to 35,123 between 1999 and 2008. Such a massive rise must be at least partly down to diagnosis methods (perhaps some of these would have been previously diagnosed as angina, I'm not sure.)

If you want to see what the heart attack rate looks like when that particular diagnosis is excluded click here. Again the various smoking bans do not seem to affect that overall trend.

CJS

Angry Exile said...

Out of interest did you find figures for the Northern Territory? I think they've either recently caved in and brought in a ban or are just about to, so for the period up to 08 wouldn't they be a rough control? Sure, pretty small population but then so has the ACT.

Snowdon said...

I've got the figures for NT but, as you say, it's a very small control group to use (still much bigger than Helena, of course...)

Probably better to consider South Australia as the control group as they had no smoking ban until the last 6 months.

CJS

Anonymous said...

James Le Fanu has dug up some interesting figures on the decline of heart attacks. He takes the view that the 20th century rise and fall was caused by an infectious agent (in his book he suggests Chlamydia):
http://www.jameslefanu.com/research/the-case-of-the-missing-data
Tony

Frank Davis said...

I think that the chart that I saw was the one suggested by Fredrik Eich and also shown in the rather delightful James le Fanu piece, from which I will quote:

The picture that emerges is so dramatic it is hard to imagine how it could have been overlooked. Starting with the United States, Canada, Australia, and New Zealand (fig 1a), the rate climbs steeply throughout the 1950s to a peak of around 600 per 100,000 in the mid-1960s before falling equally precipitously year by year over the subsequent 30 years to around 200 per 100,000. This is an extraordinarily striking picture of a disease that has risen and fallen in parallel in these countries over a period of 50 years. When we turn to fig 1b we see that, after a 10 year lag, the same pattern becomes apparent in western Europe...

If I put together this with Chris' graphs above, it suggests that in Australia, heart attacks (myocardial infarctions) peaked in the 1960s, and then fell for the rest of the century, and are now rising again. I'm a bit puzzled at Chris' suggestion that the recent rise might be due to changing diagnosis methods. On the face of it, it would seem that heart disease is increasing. Is this true elsewhere also? Or is it just Australia?

Snowdon said...

Frank,

In Europe and the US the general trend is downward and has been since the 60s (as Le Fanu says). This is why I'm intrigued at the rise in Australia. There may be good medical reasons why the rate is going up there but I find it unlikely that acute subendocardial myocardial infarction has really increased seven-fold in the space of ten years. I'm in no position to speculate as to quite what's happened. Someone like Michael Siegel or Brian Bond would have more of an idea.

From my point of view, I'm interested in whether the smoking bans had any discernible effect on the rate, regardless of which direction the rate is heading. They didn't.

Le Fanu makes an interesting case in The Rise and Fall of Modern Medicine, which I heartily recommend.

TheBigYin said...

Chris, I see that your post gets a mention on Siegel's blog.

http://tobaccoanalysis.blogspot.com/2009/10/data-from-australia-show-no-effect-of.html