Wednesday, April 11, 2007

Busting modern medical myths

In the early days of medicine, physicians might diagnose patients using bumps on their head, or dispense a couple of leeches to draw off "ill humours". Yet a medieval doctor might give a more confident response than his modern equivalent if a patient asked for the evidence to support their treatment. These days, it seems many of our "tried and tested" approaches to disease are nothing of the kind.

Researchers writing recently in the British Journal of Surgery concluded the practice of daubing patients with a disinfectant skin gel prior to operations made little or no difference to the rate of infections they suffered afterwards. Simple soap and water was just as effective. However, despite this, it's more than likely that, in future, waking up after your operation in many British hospitals, you'll have that tell-tale orange stain around your wound. You'll have been given a treatment that doesn't work.

This isn't a single example. Many techniques in common use today don't have cast-iron evidence that they do any good. In some cases, firm evidence suggests the opposite is true. Andrew Booth, from the School of Health and Related Research (ScHARR) in Sheffield, is assessing the proportion of modern treatments that are "evidence-based" - supported by "randomised controlled trials", which, if run correctly, give the best view on the value of a drug or device.

In the UK, researchers have assessed this in a variety of different parts of the health service, from busy GP surgeries to specialist hospital haematology units. In many units, between 15% and 20% of the treatments offered did not have a shred of worthwhile evidence to support their use. Andrew Booth said the medical establishment was well aware of this. "The public might be surprised at the low number of treatments which have evidence that they work - but doctors might be surprised that it is so high," he said. He added that frequently, even when new research suggested clearly that doctors should stop using a particular treatment, nothing changed.

Michael Summers, chairman of The Patients Association, said patients would be "really surprised" to learn how little of what doctors did had been proven to work. "We need to improve medical training, to make sure that doctors do know more about the effectiveness of the drugs they are prescribing," he said.

One of those doing this is Professor Paul Glasziou, director of the Centre for Evidence Based Medicine at Oxford University. "I try to change the way individual doctors work," he says, "but really, the main thing we can hope to do is change the next generation of medical practitioners." He can list dozens of examples where treatments are still widely used despite it being clear that all they give patients is side-effects. "An example is PSA [prostate specific antigen] screening for prostate cancer. What the best studies tell us is that patients who have the test are equally likely to die from prostate cancer compared with those who don't," he says. "This actually does harm, because patients who test positive may undergo unnecessary prostate surgery. But the test is still being carried out."

Even a simple antibiotic eye-drop prescription for a child's minor infection is likely to make no difference, and may help make the bacteria involved more resistant to treatment, he says.

Part of the problem for doctors is the sheer quantity of research emerging from hospitals, universities and laboratories across the globe. "There are 90 new randomised controlled trials published every single day - this flood of information makes it very difficult for any doctor to stay up to date." And when the evidence is disregarded, Prof Glasziou says, patients can be harmed. When doctors measure blood pressure for the first time in a patient they should check both arms, as the readings may differ significantly. But Prof Glasziou says this guideline isn't followed everywhere. "I know of one case where a patient was being taken on and off his medication every couple of months simply because every time he visited the doctor, the reading was taken from a different arm. "There are a lot of good things out there, but an awful lot of myths as well."


Australia: "Healthy" school menus help Maccas most of all

Pity about the parents trying to raise funds via heavily regulated tuckshops

HEALTHY canteen menus forced on to NSW schools to fight obesity are being openly snubbed as students order in pizzas, sell bootlegged Coke and leave school grounds to eat at fast-food outlets. A Daily Telegraph investigation has revealed students are resisting the low-fat menus - and private canteen operators are battling to survive with higher labour and ingredient costs. Canteen bosses estimate their revenue is dropping by up to a third as students take their business elsewhere.

Pizza, Chinese takeaway and other fast-food deliveries to school playgrounds are becoming commonplace as students tire of salads, wraps and low-fat pies and diet soft drinks to order in lunch on their mobile phones.

Last Wednesday at Granville South High School at 1pm a pizza delivery man was photographed in action outside the front footpath preparing to make a delivery of two family-sized pizzas. Nearby Villawood Domino's Pizza manager Mohammed Ahsan said his business did make deliveries to Granville South and other schools in the area. "We have a policy not to refuse a delivery to anyone," Mr Ahsan said.

Government and most private schools began phasing in the NSW Healthy School Canteen Strategy in 2003 following a childhood obesity summit. Last year alone more than $600,000 was spent implementing and promoting the scheme to convince schools to speed up compliance. This year all sugar soft drinks were banned. Under the dietary guidelines, "red" foods such as salty snacks and fatty foods are limited to two days per school term. Canteens are supposed to fill the menu with "green" foods such as wraps. "Amber" foods like low-fat pies should be used sparingly.

Also at 1pm last Wednesday, Engadine High students in uniform were dining out at Engadine McDonald's. The senior students, who were happy to be photographed, were not breaking school rules by being there. They said canteen food was "expensive" and not always appetising.

Duncan's Catering boss Duncan Irvine, operator of 38 public high school canteens, said the healthy foods policy was "naive". "The most profitable business to own now is a corner store near a school - they are now getting all our business," he said.



Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.