Tuesday 22 June 2010

Preventable deaths

Today—if you're in Britain—you may well hear the latest opinions from NICE. In a nutshell, they've come up with some more nanny state policies to control what you eat, which vary from the predictable to the surreal. According the the Telegraph, their schemes include...

• Low-salt and low-fat foods should be sold more cheaply than their unhealthy counterparts, through the use of subsidies if necessary

Thereby forcing people who don't eat in a government-approved way to subsidise those who do. No thanks.

• Advertising of unhealthy foods should be banned until after 9pm and planning laws should be used to restrict the number of fast food outlets, especially near schools

Preventing businesses from opening near schools is a horrendous idea from the point of liberty, not that NICE would be interested in that. And the advertising ban won't make any difference—it didn't with alcohol—and it's impossible to define 'unhealthy' anyway, because what counts is the overall diet, not specific items in the diet. (On the other hand, if it gets the current McDonalds advert off the screens, I could be persuaded to change my mind.)

• The Common Agricultural Policy should focus more on public health, ensuring farmers are paid to produce healthier foods

What? Farmers produce fresh fruit, vegetables and meat. How are these supposed to be made healthier? It's the processing and cooking that may (or may not) make them less healthy, not the growing of them. Unless, of course, NICE want them to be grown organically, in which case they're haven't been paying attention.

• Action should also be taken to introduce a “traffic light” food labelling system, even though the European Parliament recently voted against this

Well, quite. So forget it. What is with public health campaigners thinking they can override the EU? (See minimum pricing.)

There's more of this at the Telegraph and it all follows the anti-smoking blueprint, natch. My main reason for mentioning it is not to talk about the policies themselves, but the obligatory death toll NICE have conjured up to generate the column inches.

40,000 deaths a year due to junk food, says health watchdog Nice

I've wondered for some time what would happen if you added up all the 'preventable' deaths claimed in reports like this. I've never got round to doing a proper estimate but as a very rough, back-of-the-envelope calculation, here's what I've come up with...

As a starting pointing, there are about 490,000 deaths a year in England and Wales (ONS, 2008). Of these, 175,000 involve people aged 85 or over. It's surely pushing it to describe these deaths as 'preventable', so lets exclude them, leaving a total of 315,000.

Of those 315,000, there are some that even the most eager public healthist has yet to blame on lifestyle. For example:

Intentional self-harm: 8,000

Flu/pneumonia: 11,000

Accidents (including traffic accidents): 13,00

Alzheimers/Parkinson's/motor neuron disease: 7,000

There are many, many others but let's be ultra-conservative and just exclude these 39,000 deaths. That leaves us with a total of 276,000.

Now let's look at how many deaths are attributed to specific causes in the newspapers:

Junk food: 40,000 

Smoking: 106,000

Alcohol: 40,000

Obesity: 30,000

= 306,000 deaths

In other words, we seem to have more deaths from the estimates than we have bodies in the graveyard. Even with the implicit, if ridiculous, assumption that every cancer and every heart attack is preventable, the figures don't add up (and we still haven't taken into account things like fires, assaults, drownings, murders and contagious diseases).

This, of course, is a very crude way of working it out—most of these estimates include Scotland, for one thing, and there will be some overlap between 'junk food' and 'obesity'. Nevertheless, I suspect that if a fuller analysis was carried out, we would still find that not only is every single death 'preventable', but there are not actually enough deaths to go round.


Paul said...

Absolutely agree with you Chris,

Been wanting to add up those figures like that for a while. The flip side of that is adding up how much various conditions cost the economy. I am pretty sure those figures too would outstrip the capacity.

Angry Exile said...

Agreed. I've also been wondering for a while if we added up all the things that are supposed to kill people if we'd find that anyone actually died from natural causes at all. Currently it would seem some do since you've left wiggle room with your over 85 section, though taking the health-nazi position surely some of them would have lived longer. I think it was right here on VGIF that I saw a nicely sarcastic remark about long term cigar smoker Winston Churchill having his life cut tragically short at the age of 90. Presumably the zealots would think he might still be sitting in the Lords dispensing sage advice had he been, like his most infamous opponent ;-), a non-smoker.

PT Barnum said...

Air pollution: 50,000
Medical accidents and errors: 40,000

Obvious ways of reducing unnecessary deaths: ban cars, lorries, factories, power stations and doctors. Easy. 90,000 people will survive who would otherwise have snuffed it.

Fredrik Eich said...

A representative of NICE used the pretended post smoking ban reduction in heart attacks as an example of interventions that work on breakfast TV this morning. It rather diminishes confidence that NICE know what they are taking about.

Unknown said...

Yes and I bet a large proportion of the rest of these statistical deaths are in the over 70's bracket as well.
Ah ! the health lobbies myth of eternal life for carrot munchers.

Anonymous said...

You can read the expert testimony relevant to salt here.
Most of the evidence doesn't stand up to scrutiny. The only randomised controlled intervention study referred to is [28] from 2007, which seems to be the first randomised controlled study carried out. The link is here.
The rapid responses are interesting. Much is made of what proportion of each group were smokers. I'm not a medical doctor, but the reductions in bp seem very small. The intervention groups received a lot of tutoring about nutrition, which could have influenced their later behaviour. One of the reponses points this out. There was no significant difference in toatl mortality, which is what should be tested for. Lowering salt may decrease CHD but cause death in other ways. I'm interested to know others think.

Leg-iron said...

People are just not dying fast enough to keep up with the data.

I expect the NHS will find a way to sort that out.

Christopher Snowdon said...


Yes, 325,000 of the deaths involve people 75 or older. 165,000 are under 75, including 79,000 who are 65-74.

Anon 14:30,

In Jan 2008, it was reported that 70,000 deaths were due to 'poor diet', including 42,000 from not eating their 5-a-day and 20,000 from too much salt. Not sure if this was based on the 2007 BMJ study you mention?

Carl V Phillips said...
This comment has been removed by the author.
Carl V Phillips said...

While I certainly agree with you that some or all of the "blame the victim" body count estimates are high, be careful about this criticism -- it is not legitimate. Diseases and deaths always have multiple component causes, all of which can legitimately be called the cause (which is to say a necessary -- not sufficient -- cause of that death or disease at the particular time). So an individual may well die from smoking AND obesity AND eating junk food, and it is perfectly legitimate to say that had any one of these conditions been eliminated the death would not have occurred so soon. Someone who was killed by a drunk driver because a medical error prevented him from being saved in the hospital is a death due to alcohol use, motorized transport, and medical errors, so the causes add up to 3 for the one death. Thus, there is no reason to expect they would add up to the total. Indeed, they should add up to well more than the total if you have a rich enough list of causes.
--Carl V Phillips

Angry Exile said...

Carl V Phillips, wouldn't the word "factor" be more appropriate than "cause"?

Anonymous said...

What Carl says would not be how the man in the street interprets these statements; nor myself. Doesn't the technique of attributing deaths, about which much has been written, allow, in effect, for something causing a fraction of a death, and hence that the deaths due to different causes then sum to the total? Maybe you are saying that bringing death forward, even by a day, is causing a death? If so, this is misleading.

Carl V Phillips said...

Responding to Anonymous:
I agree that this may not be how the man on the street interprets it, though I suspect if pushed that man would not actually be able to clearly state what he thinks it means. That is one of the problems with reciting raw scientific information to people who do not understand the science. Most people do not understand a relative risk statistic, but are barraged with them. But even descriptive statistics -- which most people probably think they understand at first blush -- are subtle. Nothing causes a fraction of a death -- it either causes it or not (see below). There is no obvious way to assign fractions.

As for bringing a death forward by merely one day, that is a fundamentally different question. And, yes, you could argue that a death that is accelerated by just one day by a particular cause should not be attributed to that cause for purposes of assessing public health statistics.

Angry Exile said...
Carl V Phillips, wouldn't the word "factor" be more appropriate than "cause"?

Continuing on from the above... No. Cause is exactly the right word. It is the right word in the science of epidemiology (which is the source of this information) and is also the right word based on the usual intuitive definition. The latter, which is technically translated in epidemiology and most other sciences, is that in the absence of the particular influence, the particular outcome would not have occurred.

The word "factor" is one of those that often gets used because someone does not want to admit that they are making causal claims, even though that is exactly what they are doing. It doe not really mean anything. E.g., the phrase "risk factor", as used, has at least three or four different very distinct meanings, and therefore is worse than useless.

Following the above, it is easy to see why everything has multiple causes. Every death was caused by not only some disease, but also by birth of the individual in question, the evolution of humanity, the big bang, etc. This is part of why assigning fractions would not make sense, as noted above.

So (re Angry's other post) if the individual would not have gone outside absent his smoking habit, then, yes, smoking caused his death, as did the alcohol that caused him to pass out, the weather that caused those to result in hypothermia, as well as, perhaps, his failure to put on a coat, his companion's failure to look for him after he disappeared, cutbacks on foot patrols by the police, and any number of other things.

The summary point is very simple: Everything has an infinite multitude of causes. For a particular outcome (e.g., death) we typically identify a particular set of them as the causes we are interested in intervening on (e.g., drug use, diet, medical tech), but there is nothing magical about that list. There is no reason to expect that those causes will not overlap in many cases, and once that list is made rich enough, overlap is inevitable.

Note that I am able to spontaneously write an essay on this point because it is a very common misconception that has to be explained to first-semester students and many others.

Christopher Snowdon said...

Thanks Carl for the clarification. I knew there would be some overlap but I didn't realise there was quite that much. Well worth knowing.

Fredrik Eich said...

The way I see it is that although one can only die once, one can have one's life saved many times. But is there not a case to say that certain causes make it into
the public consciousness partly out of fashion? For example, no one I hope would say "gay sex causes AIDS" in the way people are happy to say "smoking causes lung cancer".
Virgins are not promoted as the gold standard of behavior for sexually transmitted diseases in the same way that never smokers are the gold standard for smoking related diseases. One would have thought that banning recreational sex would prevent many sex caused deaths and it would then only be a small step to insist on artificial insemination.

Anonymous said...

I am anon. Thanks for clarifying that Carl. So if "90% of lung cancer deaths are due to smoking", getting rid of smoking wouldn't result in one tenth the number of deaths. That makes sense mathematically but is very unsatisfactory otherwise.

Carl V Phillips said...

Unfortunately, it is a bit more complicated than that. It is actually the case that if you had a population that had 1000 lung cancers and smoking caused 90% then if you eliminated smoking then you would eliminate 900 of them. However, it might also be that 100 occur because people are exposed to both smoking and radon, in which case smoking is still the cause but so is radon. If you eliminated the radon exposure then there would be 900 total cases. (Let's assume that radon is not causing any cases by itself, apart from smoking.)

Here is where it gets complicated. If you eliminated radon, then smoking would be causing only 800 cases. That is, by changing other causal co-factors, smoking would not be causing as many cases. (Even more complicated, it would now be causing only 88.9% of the cases. To avoid the confusion of the percentages, I will just stick to counts.) This would mean that eliminating smoking would now only eliminate 800 cases in this population.

Taking this further, a death from lung cancer among the 900 is caused by both smoking and the failure to have a good cure for lung cancer. Thus, if a good cure for lung cancer were invented, the number of deaths caused by smoking would be reduced. Nothing changed about the nature of smoking or what it did to the body, but what it caused did change.


Anonymous said...

Thanks Carl. I had in mind smoking and radon but with the model that that smoking and radon were in a race with each other to give certain susceptible people LC (so that radon would here be causing cases on its own). In this case, removing smoking would not save a LC individual who gets LC caused at a later date by radon, even though this individual's LC was originally due to smoking.