By Dr Malcolm Kendrick
Most of us find public health advice very confusing and contradictory. Sunshine: need more or less? Butter: artery blocker or weight dropper? Statins: heart protector or muscle ache recipe? And mammograms: odds on a good or bad outcome are worse than you think.
That is why we need Dr Malcolm Kendrick. Known as a fierce and persistent critic of statins he has now turned his sceptical eye on the advice given about various other lifestyle choices. You may be slightly less confused after you’ve read his revelations of ways advocates can spin their advice as vigorously as any politician. Here Malcolm summarises his latest fascinating and hugely informative book Data Doctoring: How to Sort out Medical Advice from Medical Nonsense (Columbus Publishing, £14.99) and explains why none of it can save a life.
We are being doctored to death. GPs’ surgeries and public health bodies routinely warn of hazards lurking all around us. They tell us sunshine is bad. Drinking alcohol is bad. Cholesterol is bad. Saturated fat is bad. Being overweight is bad.
But these warnings only ever tell one side of the story. Actually we need the sun, modest drinkers are healthier than teetotallers, and overweight people can live longer. But the medical profession has a terrible fear that it may not have the answer, so doubt and conflicting evidence is simply swept aside.
As a result, most people don’t even know there is another side to the story. So they take on faith that they need regular testing for signs of cancer, for high cholesterol, for raised blood pressure. But these simple messages can have very damaging results.
People end up on pills for the rest of their lives, believing that this will give them a better chance of avoiding disease. And your chances of being put on a pill to prevent something have been growing, because the threshold of what doctors consider ‘healthy’ has been lowered.
How cholesterol’s safe level has been dropping
When I graduated in medicine in the 1980s your cholesterol was considered high if it was 7.5. Then, about ten years ago, it dropped to 6.5. Then it went down to 5.5. It’s now 5, or 4.5 if you’ve had a heart attack or stroke. The same fall has happened with the healthy level for blood pressure.
And because of rising pill consumption, you could be taking eight or more drugs a day in your sixties.
But this isn’t science; it’s faith and belief. Medicine should be constantly moving forward, improving, accepting that there may be other ways of looking at things. Faith and belief hinder that.
Of course, some people are much happier taking every precaution — I have friends who cover themselves with suntan lotion and fear that every lump is skin cancer. But I don’t need to feel the artificial safety net of tests and medication designed to reduce risk — I don’t know what my blood pressure is.
It may be that I’m more of a risk-taker generally: I don’t care if I get a suntan, I used to ride motorbikes and I’ve set off an avalanche after ignoring the warning signs.
How vested interests confuse the picture
But whether you are anxious or blithe like me, I believe everyone has the right to know the real risks and benefits of tests and treatments so they can make up their own minds. Currently, that’s almost impossible because there are too many vested interests telling and promoting just one side of the story.
We often get fooled because talking about risks involves maths and most of us are more scared of maths than cholesterol and saturated fat combined. But the basic principles are easy to understand.
Take the question of whether it’s worth having a mammogram or being screened for prostate cancer. Official websites make these measures seem like a safe and sensible precaution.
There is no mention of the risks, apart from a tiny one from a small amount of X-rays from a mammogram. The section of the NHS website on breast cancer screening says you’d get about the same amount from flying to Australia and back. The possibility that you’ll have invasive treatment you don’t need as a result isn’t mentioned.
What’s stressed is the benefit: it reduces your chance of dying from the disease by between 20 and 30 per cent. Sounds good.
The realistic view of mammograms is less glowing
But there is another way of describing the benefit that is just as accurate but a lot less glowing. You would have to scan 1,000 people every year for ten years to save one life. Some might decide that’s not worth it, especially as your chances of having false positive results — which could result in invasive tests and possible surgery — are potentially greater than the chances of benefiting.
Drugs such as statins also look good when percentages are used. It’s often claimed that statins can cut your risk of a heart attack by 25 per cent. But the figures don’t look so good when actual numbers are used, as I shall explain in a minute.
I first became sceptical about statins and the supposed benefits of lowering cholesterol at a medical conference in Scotland 25 years ago. Scotland had the highest rate of heart disease in the world.
We were told that we were putting our hearts at risk by eating too much fat, which raised our cholesterol, which in turn created blocks in our arteries.
But when I started investigating, I first discovered what was later known as the ‘French paradox’. Even though they ate much more fat than us Scots and took less exercise, their rate of heart disease was six times lower.
Statins and the significant diabetes risk
Long hours in the library dug up more ‘paradoxes’, such as the Swiss and the Masai tribe. They both also ate lots of fat and had low cholesterol. When I became a GP, I realised that I was seeing far more people with serious side-effects from statins than the clinical trials predicted.
The official line is that one patient in 500 would get significant side-effects. So, with around 600 patients on statins, I should only ever see one with serious side-effects.
But I have seen around 200 patients with serious side-effects. New research supports the idea that side-effects are much more common than originally claimed. As a major U.S. study published a few weeks ago found that if you take statins for ten years, you have a greater chance of developing diabetes than you do of avoiding a heart attack as a result.
The older you get, the more you’re going to have to make judgments about drugs because you’re going to be offered more and more of them. The elderly patients in the rehabilitation unit where I work are typically on ten drugs. Could it possibly be that if you stick ten different drugs into an elderly person, the adverse effects and inevitable drug interactions may possibly, just possibly, overwhelm any possible benefits?
What we do know is that taking people off drugs can make them live longer and be dramatically less likely to need emergency care. Being able to discuss the benefits of cutting your drug intake would almost certainly make your final years more pleasant.
Here, I present my guide to reading behind some typical headlines, to help you make informed decisions about taking that pill you’re being prescribed.
Putting ten million on statins saves 50,000 lives a year, or does it?
Nearly 15 years ago, the press release from Oxford University announcing the results of the ‘world’s largest randomised trial’ of statins claimed that putting ten million people on them would ‘save 50,000 lives a year’. This is a common claim for prevention that should set alarm bells ringing.
In fact, no treatment can ever ‘save lives’ because we are all going to die.
Prevention can only let you live longer. So what you want to know is: how much longer? That’s what these sort of studies almost never tell you. Yet this study is still used today to prove the benefit of statins. So how much extra time would people get? A few years?
Actually it’s about three months, the figure calculated for me by a professor of statistics from the Medical Research Council. A more useful way of presenting the results of this trial would be this. If you gave statins to 200 people for a year, just one more would be alive at the year’s end.
The other 199 would die at the same time they would have done and at least 20 would suffer serious side-effects.
Red meat raises risk of dying from heart disease
Stories reporting healthy eating research often have headline such as this. Reading it you might think: Sounds like I should eat less meat. In fact, the original study said that meat was associated with an increase in heart disease and death. Confusing an association with a cause can make lots of things seem risky when they aren’t.
The meat study is what’s called an observational study, it monitors people to see what happens when their habits or behaviour changes. But when two things happen together — less meat, fewer deaths — there is a natural tendency to assume one caused the other.
But to show a cause you’d have to feed one group a lot of meat and another not so much and then see which had fewer heart attacks. People would be put in the more meat or less meat group at random.
And in an observational study there would be many things that could raise or lower death rates. In the meat study those who ate the most meat also smoked the most, exercised the least, ate more and were more likely to have diabetes.
Cancer drug increases survival by four months
There is a fascinating and little known difference in the way the benefits of statins and cancer drugs are calculated. No one ever tells you how much longer you might live from taking a statin but the benefits of all cancer drugs are calculated in terms of ‘increased life expectancy’.
The result is that cancer drugs don’t seem very effective — an extra three to four months is not uncommon. But that is actually far more impressive than the benefit from a statin.
This is because those few months make up the average increased survival time for everyone on the drug. Some will do much better, some much worse but almost everyone on a cancer drug will live a bit longer.
But that is not true for a statin. After years of treatment only one extra person out of 200 will live a bit longer — probably a few months — the rest will die at the same time as they would without it.
Cancer drugs are seen as being very expensive for every extra month of life they give, but looked at this way they might actually be better value than the far cheaper statins which are many times less effective.
Two glasses of wine triple cancer risk
We are all very bad at estimating risk. We are often terrified of things that are extremely unlikely to happen, for instance a shark attack. Yet we happily drive, which is much more likely to kill us — in the UK car crashes kill eight people a day.
None of this is helped by the fact that the true risk of something happening is often hidden behind horribly misleading statistics, and this is no less true for drug treatments and preventative programs, where it is used to magnify the risks of behaviour health authorities disapprove of such as alcohol.
One press release reported that regularly drinking two glasses of wine tripled your risk of mouth cancer. Scary.
What wasn’t made clear was that in the UK out of 100,000 people just 2.5 will develop mouth cancer. A risk of 0.0025. Tripling it is still less than 0.02 per cent. Not so scary.