One of the more enjoyable (and sometimes inflammatory) habits adopted by the excellent Dr Crippen is his posting of what he calls ‘Quacktitioner Alerts‘, which, in common with Ben Goldacre’s ‘Bad Science‘ provide a valuable public service by highlighting all manner of crap science, piss-poor practice, misinformation and general snake-oilery.

I’m happy to say that I’m very much a fan when it comes to a good debunking, whether its Crippen’s quacktitioners, Goldacre’s bad science, Penn and Teller’s glorious ‘Bullshit‘ or the daddy of the all, and the man who should be regarded as the intellectual father of fisking, James Randi.  And if one wishes to find good quality source material for a good debunking, then I can heartily recommend that you open any newspaper and scour the news sections for the words ‘health correspondent’.

Which bring me to this patronising effort from today’s Indy:

Obese people twice as likely to get Alzheimer’s

By Jeremy Laurance, Health Editor- Published: 29 June 2007

Britain’s obesity explosion could trigger a second even more serious epidemic – of dementia. Experts warned yesterday that our fondness for fast food and resistance to exercise was not only causing waistlines to bulge – it is also damaging our brains.

Obesity is bad for you. This is well established.
It increases your risk on winding up with all manner of nasty shit, like cardiovascular disease, diabetes, sleep apnea, gallstones, hernias, fatty liver disease, renal failure, osteoarthritis, stokes, that most people would much rather not have to deal with.

But clearly none of shit is scary enough to stop people pigging out at Maccy D’s, so now the ‘experts’ are wanting to tack going doolally-tap on to the list to make the whole business ever scarier.

An estimated 700,000 people have dementia in the UK and the number is forecast to rise to as many as 1.5 million over the next 50 years, according to the Alzheimer’s Society.

Yes, very nice. But how does that relate to population demographics?

Look, this is not difficult. If 700,000 people have dementia in the UK now, on its present population, and – hypothetically – the population of the UK doubles in the next 50 years, then we are likely to see double the number of dementia cases, but the risk of being one of them will have remained the same.

Let’s make that a bit easier to understand. If two out of every five cats are black, and you own five cats, you likely end up with two black cats, and if you then buy five more, you’ll get another two black cats, giving you four black cats, which is twice the number you started with – but, you’ll also have ten cats (and a serious cat food bill), which is also twice the number you started with.

That’s the basics, let’s look at the numbers.

Well, the main incidence of dementia, which means not just Alzheimer’s but other forms, tends to be in over 60s, so let’s stick just that population to begin with (to get a general picture of thing), which is currently estimated at just over 12 million people. Track on fifty years, using the National Statistical Office’s population pyramid doodad, and the estimate for the age group is 17.7 million, so it looks as if population change isn’t going to account for the full projected increase.

But, hang on – we can actually be a bit more specific than just ‘over sixties’.

The primary risk factor for the most common form of dementia – late onset Alzheimer’s -is aging. At age 65, 2-3% of people show signs of Alzheimer’s, with the probability doubling every 5 years. As for the second most common form, vascular dementia, there are a number of contributory factors that come into play, but aging is certainly one of them, so its reasonable to take another look at the figures but using a higher age group, where the risk factors and incident are greater – Say the over 70’s

That gives us 5.8 million currently, and an estimate of 9.5 million by 2057. Still not the full doubling effect but the extent to which an increased incidence of dementia in 50 years time may stem purely from population demographics is creeping up as the primary risk factor – age, increases.

Let’s take it up again – to over 80. This give a current population of 1.45 million and a projected 2057 population of 2.62 million, and the gap narrows again, leaving only 10% or so of the doubling effect unaccounted for by ageing and population change – and that’s about as far as we can take as the population doodad tops out at 84 years of age.

The point in all this is that if you want people to make informed decisions about their health, then you have to explain things to them properly, not just lob a couple of big scary numbers at them and hope their shit themselves at the thought that they might one day end up as a statistic. As Stalin correctly noted; ‘one death is a tragedy, one million deaths is a statistic’ – people don’t engage with big scary numbers at a personal level. They can’t form a mental picture of wat 1.5 million people drooling insensately in their hospital beds looks like, let alone picture themselves as being one of them. To get you message across, you have to stop patronising people and explain the risks properly, so they get the message at a personal level and can imagine themselves having that kind of future ahead of them.

As this stand, just on the base stats, population changes look unlikely to account for all the increase in numbers over 50 years, so it does look very much as if other factor are also upping the probability of dementia.

But if the population goes on getting fatter, the total could rise to 2.5 million, said Clive Ballard, director of research at the society. “Obesity is a huge risk factor,” he said. “People who are overweight at 60 are twice as likely to get dementia at 75. We have a public health epidemic of dementia given the ageing of the population, and it is essential to reduce the risks. If these factors are not controlled, it may not be 1.5 million but 2 or 2.5 million people affected.”

Currently one in 20 people aged over 65 has signs of dementia, rising to one in five over 80. Increasing obesity could double the incidence among over-65s to one in 10, said Mr Ballard.

Again, Ballard is lobbing yet more big number into the pot without giving any explanation as to why obesity is such a big deal and unless people understand the causal links between obesity and dementia, the message isn’t really going to sink in.

The mechanism of how obesity affects the brain was unclear but it encompassed diet, exercise and physiological effects. Research has shown that people who eat a diet rich in fruit and vegetables have an up to 40 per cent reduced risk of developing dementia. Exercise has a similar effect.

Studies also suggested that amyloid protein which can build up in the brain, causing damage to nerve cells, is cleared from the blood more efficiently when cholesterol levels are low. High cholesterol could increase build-up of the protein and hasten the onset of Alzheimer’s. Neil Hunt, chief executive of the Alzheimer’s Society, said: “I remain genuinely mystified why this is still such a low priority. The cost of dementia to individuals, families and the state is £17bn a year. Now there is research suggesting dementia is not as inevitable as we thought. There is no cure but evidence is building that lifestyle choices make a difference to risk.”

Let’s stop there.

Having started out by lobbing numbers at people without explanation, we’ve now gone to the opposite extreme of trying to freak people out with indecipherable gobbledygook.

This section starts out by admitting that they don’t know exactly what the link is between obesity and the brain, drifts of into the usual ‘research has shown…’ stuff which tells us that they think that exercise and eating fruit and veg is good for us – no shit, Sherlock – and then heads off into medical country with all the talk of amyloid proteins, which are ‘suggested’ could be building up in the brain and causing nerve damage.

In science, if something is ‘suggested’ then that could mean anything from ‘we’ve got some promising initial data but not enough to be sure’ to ‘we’ve got a hunch it might be this and would like some cash and a good stock of monkeys to dissect, please’.

We’re still, even at this stage and despite the headline, not entirely sure whether what this all about is dementia in general, of which there are several kinds with different causal factors, or specifically about Alzheimer’s – which is what it looks like from the comments at the end of waffle about cholesterol and amyloid proteins – largely because throughout the article has used ‘dementia’ and ‘Alzehimer’s’ as interchangeable references rather be clear and precise about what they’re referring to.

We’re also told that the Chief Executive of the Alzheimer’s Society is ‘mystified’ as to why it is ‘such a low priority’ when ‘dementia’ (type unspecified) costs individuals, families and the state £17 billion a year – that last statement is perhaps best understood if you adopt an Irish accent and a grizzled and slightly aggressive tone of voice and then repeat after me: Give us your fucking money!!!

Call me a tad pedantic, but I can’t help wondering if at least part of the explanation for the ‘low priority’ thing might have something to do with the observation that rather a lot of those trying  to ‘educate’ the public about the risks and consequences of dementia appear incapable of expressing themselves in clear and simple terms that everyone can fucking well understand.

Launching a booklet, Be Headstrong, he said that five steps were necessary to reduce the risks – do not smoke, eat less saturated fat, exercise regularly, lead an active social life and have blood pressure and cholesterol checked regularly. “If we could delay the incidence of dementia by five years we could reduce its incidence by 50 per cent,” he said.

That last statement; “If we could delay the incidence of dementia by five years we could reduce its incidence by 50 per cent” is a staggering piece of logic.

You cannot ‘delay the incidence of dementia’ because incidence is a measurement of quantity and proportion, not time. The incidence of a condition is the number of people with the condition divided by the size of the total population and usually expressed in terms there being n cases per 1,000 to make comparisons between different populations easier.

You can delay the onset, the point in time at which the condition begins to develop, which will push back the increasing probability of developing dementia to a later stage in life, but that, in itself, will not alter the incidence of the condition.

What will alter the incidence of a condition or disease is:

a) prevention, say by vaccination (which is inapplicable in this case),

b) effective treatment of, or cures for diseases/conditions that may cause dementia as a secondary effect, such as syphilis, tumours, hyperthyroidism and vitamin B1, B12 and A deficiencies (which is where some element of the eating fruit and veg comes into play) . These account for only about 5% of all dementias, or

c) a reduction in risk factors/behaviours that does result in a lower incidence because limiting exposure to risk results in fewer people developing the condition. This is particularly applicable to vascular dementias arising as a consequence of cerebrovascular disease resulting in neurological damage by way of strokes, ischemia, aneurysms and embolisms.

If we’re talking about dementia in general, then any of the above could reduce the incidence of the condition overall, but only to a limited extent as time (and ageing) is a also a factor in dementia due to vascular degeneration.

If Hunt is referring specifically to Alzheimer’s, for which the three main causal hypotheses, at the present time, all rely on biochemistry and genetics,  then delaying onset will have no impact on incidence other than in terms of it being linked directly to ageing. In other words, if delaying the onset of Alzheimer’s by five years ‘reduces’ the incidence of the condition by 50% that can only because the 50% who don’t develop the condition have died as a result of other conditions and diseases before Alzheimer’s has had chance to set in.

Its like comparing statistics for cancers and heart disease between now and the 1840’s – the incidence of both will be much lower in the 1840s, not because Victorian England was a healthier place to live but because life expectancy has increased massively since then as public health initiatives and developments in medicine and healthcare have taken out of play most of the nasty shit that used to kill people long before stuff like cancer and heart disease had a chance to kick in.

Great message, eh? If you don’t fancy ending your days covered in dribble and with a vivid memory of the 1979 cup final and next to fuck all else besides then the secret is to die of something else before it all kicks in.

Professor Jeremy Pearson, associate medical director of the British Heart Foundation, said risk factors for heart disease were also risk factors for dementia. “We now know that protecting the heart will also protect the brain,” he said. “Treatments that reduce heart disease also reduce dementia. There are very similar pathological processes underlying both.”

Well, yes. But that information is nothing particularly new, novel or innovative – its not as if medics have only just figured out that fucking up your vascular system by living your life as a Maccy D chomping couch potato is bad for you, whether in the context of cardiovascular (heart) disease or cerebrovascular (brain) disease.

The only plus point to this article is that, for once, they’re not making a meal of blaming smoking for all the ills of old age, even though that’s just as good at fucking up your vascular system as a diet of burgers, Big Brother and deep-fried Mars bars. I guess that what this means is that they figure that lung cancer is plenty scary enough to cover the bases when it comes to scaring the shit out of smokers already, so there’s no need to try and dump Alzheimer’s on top, while when it comes to scaring the shit out of fat boy, heart attacks just don’t have the same kind of scare factor because if it nails you it tends to get the job over and done with pretty quickly and it it doesn’t you can always change things round afterward or get things fixed up with a bypass or transplant, which is why you need to rope in something that offers up the prospect of a long, lingering and fucking undignified exit to nail home the point.

It’s the fucking Freddie Kruger school of public health medicine – scare ’em, scare ’em good and keep right on scaring the dumb fuckers until they get the message. Never mind that you could just try treating people like fucking adults, explaining the facts, and lets us figure this shit out for ourselves.

Professor Pearson is not wrong is his remarks, merely stating the bleeding obvious – which I’ve no doubt he is perfectly aware of and could happily explain in much more illuminative fashion were his remarks not simply being used as filler by a ‘health correspondent’.

Similarly…

Tony Rudd, consultant stroke physician at Guy’s and St Thomas NHS Trust, said up to one-third of the over-65s who had a stroke would develop dementia within three months. “Public health initiatives to prevent stroke and related risks are essential,” he said.

Absolutely spot-on, as you would expect from a consultant stroke physician at a well known and high profile hospital, but again he’s talking specifically about vascular dementia arising as a direct consequence of a stroke, and the headline on the article states: “Obese people twice as likely to get Alzheimer’s”

Vascular dementia is NOT fucking Alzheimer’s Disease, and unless groups like the Alzheimer’s Society are operating from a broad remit which incorporates and supports research into all areas of dementia, then they and the meejah should steer clear of conflating their specific field of expertise with other fields simply to inflate the numbers and contrive a slightly bigger scare factor.

If anyone is seriously concerned by the obesity connection to dementia then they’re currently much better served by talking, and making the bulk of any donations to, the Stroke Associations that deal specifically with vascular dementia, which accounts for 20-40% of all dementias in Western Europe – because we know damn well how lifestyle impacts on that and what you can do to limit your risks.

As for Alzheimer’s, more research is certainly needed to narrow down its main causes and any causal links to obesity, so a bit of cash in that direction is certainly not wasted, and the general advice on eating the right things, not smoking (and I am a smoker, btw) and getting your lazy asses off the couch and doing a bit of exercise is sound, if much more likely to do you a power of good in terms of stuff like heart disease and the like, where the causal links are already well established and understood.

So its not a complete washout here, the article is just badly written and rather patronising in its attitude to readers, which may well be a function of the journalism applied to the story and not the sales pitch made by the Alzheimer’s Society, who otherwise do a considerable amount of good work and are deserving of public support.

And the best advice of all – if you need more information or are worried about your health then FFS, go make an appointment with your GP for a check-up and a chat. They can explain all this far better than the health correspondent in the newspaper and may well even treat you like an intelligent human being and not an idiot.