A few years ago many people would never have heard of statins. Now more than five million Britons take the cholesterol-lowering drugs every day to prevent heart attacks and strokes.

But do they actually work for many of us? A new study has raised serious questions about whether they do - meanwhile, other new evidence has linked ­statins with severe depression and suicide.

Statins have been hailed as 'wonder pills' by doctors and drug companies. They are prescribed to anyone in Britain who is believed to have more than a 20 per cent chance of having a heart attack or stroke over the next ten years. It is hoped that, by lowering their cholesterol, the patients' death risk will drop significantly.

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© Daily Mail, UK
Extreme: Some patients are being prescribed statins even if their cholesterol levels come under the traditional category of 'normal'.
The trend for believing that any cholesterol at all is automatically bad has intensified to the point where growing numbers of patients are being prescribed statins even if their cholesterol levels come into the traditional categories of 'normal' or even 'low'.

A new study by a prestigious U.S. university calls all this into question. The research suggests a great many people may not get any benefit from taking statins - that's because it's our calcium levels, not cholesterol, that really matter, claim the researchers.

The study of 950 men and women found that statins may only help patients if they have a calcium build-up - calcification - in their blood vessels. Calcium makes arteries harden and increases the risk of high blood pressure, heart attack and stroke.

Scientists believe calcification is primarily caused by a combination of genes and ageing, along with poor lifestyle such as lack of exercise, bad diet and smoking. It's not clear why these cause a build-up of the mineral - though calcium in the diet is not to blame.

The researchers from Johns Hopkins University, Maryland, found that in the group of 950 healthy people, half had calcium build-up; they suffered 95 per cent of all the heart attacks, strokes or heart-related deaths seen in the five-year study.

The other half of the group did not have any calcium build-up and, tellingly, they suffered only 5 per cent of the heart problems that occurred. If calcium, not cholesterol, is the real issue, this might explain why 75 per cent of people who suffer heart attacks have normal cholesterol levels.

But the more immediate message, says Dr Michael Blaha, who led the study, is that patients with no calcium build-up would be very unlikely to get any benefit from swallowing preventative statins. 'Our results tell us that only those with calcium build-up in their arteries have a clear benefit from statin therapy,' he told a conference of the American Heart Association earlier this month.

He says instead of handing out statins to increasing numbers of patients, doctors should first measure patients' coronary artery ­calcium deposits using a CT scanner (a kind of X-ray machine) and give the drugs only to those with high levels.

There are compelling reasons why we should be wary of swallowing ever more statins - as many as 5 per cent of people develop serious side effects. Numerous studies have suggested we need a certain level of cholesterol in our bodies to remain healthy. People with low cholesterol levels have higher risk of suicide, Parkinson's disease and some forms of stroke.

Why suicide? A new Swedish study of 42 people who had attempted to kill themselves suggests that when our level of blood cholesterol drops, so, too, does our level of the 'feel good' brain chemical, serotonin.

There are other 'new' side-effects that have been added to the warning lists published with the packaging on statins. These include muscle problems, sleep disturbance, memory loss, sexual dysfunction, depression and a potentially lethal lung disease.

Overall, the rate of side-effects is low but, given the huge number of users, this adds up to many thousands of patients being affected.

Nevertheless, drug companies are intent on selling ever more statins, which are already the world's top-selling prescribed drugs. The drug makers would like statins to be prescribed more widely to people with normal and even low cholesterol.

Their case seems to be backed by results of a study called Jupiter, which involved more than 2,000 UK patients. The research, paid for by AstraZeneca, claimed that the statin rosuvastatin significantly cut deaths from heart attacks and strokes in men and women who had normal cholesterol levels.

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© Alamy
Expert view: Dr Mahendra Varma says statins should be put in the water supply.
The trial was scheduled to run for four years, but after nearly two years, the scientists running it declared that the early results were so strongly positive that they should stop testing and move on to publicising the good news so that everyone could benefit.

The study, published in 2008, is being seen as a good reason for giving statins to a wider group of people, not just those deemed at 20 per cent risk of heart attack.

Statins should even be put in the water supply, according to one of Britain's leading heart experts, Dr Mahendra Varma, who is vice-chairman of the Northern Ireland Chest, Heart and Stroke Association.

But a big scientific row has broken out this year over the Jupiter study. According to three expert articles in the journal, Archives of Internal Medicine, the Jupiter trial was deeply flawed.

Close analysis of the figures by French doctors found that statins did not actually achieve any real reduction in deaths, and the ­figures had been warped by commercial interference. Nine of the 14 Jupiter researchers had financial ties with AstraZeneca.

Cambridge University doctors who examined the study said the fact that it had been stopped early meant the results could be cherry-picked to make them look favourable before any longer-term problems emerged. The journal's experts added that, overall, the best evidence shows that statins do not, in fact, help people who have no evidence of heart disease.

Despite this, the British Heart Foundation says it continues to support the widespread use of statins. Judy O'Sullivan, Senior Cardiac Nurse at the BHF, says: 'It is unusual in this country for statins to be given preventatively to people with normal cholesterol levels. We think that statin drugs are useful for the vast majority of people taking them.'

And she adds: 'We don't think that screening patients for calcium build-up before prescribing them statins would be helpful, as the test would be expensive and expose people to radiation.'

But some doctors are sceptical of preventive statin treatment. Dr Matt Hughes, a GP and hospital practitioner in cardiology in Cardiff, said recently doctors should be very cautious about prescribing statins for people as 'treatment for a disease they don't have yet'.

Writing in the GPs' newspaper,Pulse, he said the best scientific evidence shows statins do not even benefit people who are considered at high risk of developing heart disease.

Dr Malcolm Kendrick, a Cheshire GP and outspoken critic of widespread statin use, says despite all the negative clinical evidence, prescription levels of statins are still rising considerably, so most people over 65 are taking them.

'Such widespread use is a tribute to the persuasiveness of the drug companies. It does not mean statins work preventively - they don't,' he adds.