They have prevented countless heart attacks and strokes and probably saved the lives of millions in the process. And despite being heralded as game-changers when they were first rolled out to the masses in the 1980s, statins have got a bad rap in recent years.
On their way to becoming one of the most prescribed drugs in the world, a host of research began linking them to a wide range of debilitating side effects — from memory loss to muscle pain, migraines and even diabetes.
It is estimated that as many as half of users stop taking them entirely or don’t use them properly because of the supposed risks, which severely limits their cholesterol-lowering powers.
But a growing number of studies have started pushing back against claims statins are the true culprit behind all of the side effects, which many experts suspect are just as prevalent among people not on the drugs.
Yesterday, a landmark Oxford University study revealed muscle pains are no more common in people on statins, despite being listed as an official symptom by the NHS and health chiefs around the world.
That research, on more than 150,000 people, concluded that the drugs are in fact caused by the natural effects of ageing.
A similar theory might also explain why the drugs — taken by 8million Britons and 32million Americans — are constantly linked to memory and sight problems.
Professor Sir Nilesh, medical director at the British Heart Foundation, told MailOnline: ‘Statins are an important and proven treatment for preventing coronary heart disease.
‘But their use has been clouded by the perception that they cause significant side effects, like muscle aches but also memory loss, sleep disturbance and erectile dysfunction.
‘However, these complaints are not uncommon in the general population for a whole variety of reasons. Therefore when patients take a statin and develop such symptoms, they understandably attribute them to the statin when it may not be the cause.’
Statins are a group of pills that stop the liver producing ‘bad’ cholesterol, known as low-density lipoprotein (LDL) cholesterol. Over time, its build-up can lead to hardened and narrowed arteries and heart disease — one of the world’s leading causes of death.
People are currently prescribed statins if they have been diagnosed with the disease, or have a family history of it. The tablets, which cost just 20p a pill and are proven to be life-savers, are taken once a day.
Here, MailOnline breaks down the biggest myths around statins and their potential side effects:
Millions are able to live normal lives thanks to the cholesterol-busting effects of statins but the drugs have been linked to numerous side-effects that put some off the medication. However, many of these supposed symptoms — including memory loss, diabetes and headaches — may actually be a result of other lifestyle factors, experts have found
Statins are the most widely prescribed drugs in the world, with around 8million Britons and 32million Americans taking them every day to cut their risk of heart complications due to high blood pressure
The NHS lists muscle pain as one of the ‘common side effects’ of statins and also suggests weakness can be caused by the drugs.
But a review by Oxford University published in The Lancet on Monday suggests the aches and pains may actually be just the natural signs of old age.
Researchers looked at rates of the side effects in 155,000 patients who took statins or placebos in 23 randomised trials.
The history of statins
Japanese biochemist Akira Endo isolates mevastatin — the first statin drug — from a fungus.
Animal trials showed the drug lowered cholesterol in dogs, rabbits and monkeys.
However, the drug was never marketed after rat trials showed it could be toxic.
Alfred Alberts discovered lovastatin while working at Merck Research Laboratories.
It was also discovered independently by Dr Endo for the Sankyo company within a year.
Merck began clinical trials in 1980, but were paused after Sankyo tests of the chemically similar mevastatin found it was toxic in animals.
But trials on lovastatin found no similar issues and in 1983 clinical development was restarted by Merck.
Lovastatin becomes the first statin to be approved by the US Food and Drug Administration (FDA).
It reached sales of more than $1billion (£858million) in its first year.
Atorvastatin is approved. It is sold by Pfizer as Lipitor and is the most popular statin in use today.
It followed the approvals of pravastatin in 1991 and fluvastatin in 1994.
FDA introduces safety warnings on statins stating a small increased risk of higher blood sugar levels and type 2 diabetes diagnosis.
In total 27.1 per cent of patients on the drugs reported muscle pain or weakness, compared to 26.6 per cent of those who were given the placebo.
After the first year of treatment, there was no difference between those given statins and those given dummy tablets.
The researchers found stronger doses carried a slightly higher risk of muscle issues, but most cases are mild.
They said the results will help patients and doctors ‘make informed decisions’ when considering if they should stop taking their pills — and should continue taking them unless the drugs are proved to cause the pain.
Lead researcher Professor Colin Baigent, an epidemiologist at Oxford, said if a patient on statins suffers muscle pain, it is ‘most likely due to other causes’.
Statins have also been linked with an increased risk of developing cataracts.
Cataracts are when the lens, a small transparent disc inside the eye, develops cloudy patches. Over time these patches usually become bigger causing blurry, misty vision and eventually blindness.
Around 330,000 surgeries for the condition are performed every year in England alone, making it the most common operation in the country. They affect around 24.4million adults aged over 40 in the US.
A series of studies over the past two decades have suggested statins may significantly raise the risk of cataracts.
But research by cardiologists at Peking University First Hospital in Beijing, China, concluded ‘there is no clear evidence showing that statin use increases the risk of cataracts’ in humans after a major review in 2016.
The review, looked at 17 studies in the US, UK, Canada, Australia, Europe and Asia, with a total of more than 313,000 patients included.
Six of the papers compared cases in people given statins or placebos and all 17 investigated the risk of cataracts with statin use. Patients were aged from 30 to 85.
Overall, there was a 13 per cent increased risk of developing cataracts in six of the long-term studies that followed statins patients for at least five years.
Interestingly, the risk was actually 11 per cent lower in more rigorously controlled studies.
Writing in the journal, the authors said: ‘Based on the present meta‐analysis of these studies, we could only conclude that there is no clear evidence showing that statin use increases the risk of cataracts.
‘The most likely case is that there is no association between statin use and cataracts. Because of the considerable benefits of statins in cardiovascular patients, this issue should not deter their use.’
Sir Nilesh told MailOnline: ‘The most likely case is that there is no association between statin use and cataracts. Because of the considerable benefits of statins in cardiovascular patients, this issue should not deter their use.’
The NHS lists memory problems as an ‘uncommon’ side effect of statins, while the US Food and Drug Administration (FDA) warns ‘some people have developed memory loss or confusion’ on the drugs’ labels.
WHAT ARE STATINS?
Statins are a group of medicines that can help lower levels of ‘bad cholesterol’ in the blood.
Having too much of this type of cholesterol — called low-density lipoprotein (LDL) cholesterol — can lead to the thickening of the arteries and cardiovascular disease.
Statins work by stopping the liver from producing as much LDL.
Previous studies have found that the drug will prevent one heart attack or stroke for every 50 people taking it over five years.
The drug comes as a tablet that is taken once a day.
Most people have to take them for life, as stopping will cause their cholesterol to return to a high level within weeks.
Some people experience side effects from the medication, including diarrhoea, a headache or nausea.
People are usually told to make lifestyle changes in a bid to lower their cholesterol — such as improving diet and exercise habits, limiting alcohol consumption and stopping smoking — before being prescribed statins.
The medicines watchdog issued the warnings because some people on the drugs reported suffering with problems after starting the medication.
But researchers have found no evidence the drugs actually cause the issue, with studies in fact showing they can help reduce the chance of developing dementia in the long-term.
High cholesterol is one of the main risk factors for the memory-robbing condition.
Experts at John Hopkins University in Baltimore, Maryland, reviewed 16 studies of more than 23,000 patients that measured people who were and weren’t taking the drug’s memory, attention and problem-solving.
The review, published in Mayo Clinic Proceedings in 2013, only included patients with no history of cognitive decline.
Three studies found there was no association between using statins and dementia, while five found the drugs actually improved the chances of staving off the condition.
Overall, people given statins had a 29 per cent lower incidence of dementia.
Study author Dr Kristopher Swiger, a cardiologist at JHU, said: ‘All medications, including statins, may cause side effects, and many patients take multiple medicines that could theoretically interact with each other and cause cognitive problems.
‘However, our systematic review and meta-analysis of existing data found no connection between short-term statin use and memory loss or other types of cognitive dysfunction.
‘In fact, longer-term statin use was associated with protection from dementia.’
Researchers said it ‘makes sense that statins could be protective in the brain against dementia’ because reducing bad cholesterol improves blood flow to the brain.
This helps prevent vascular dementia particular, which is usually caused by blockages in small blood vessels in the brain.
Statins have been widely linked to headaches since they first exploded on the scene, but some researchers suggests the drugs should actually be prescribed to people who suffer a certain type of migraine.
Around one in five women and one in 15 men suffer migraines, with a severe headache preceded by an ‘aura’ affecting vision balance and coordination in about 30 per cent of cases.
People who experience this aura have a significantly greater chance of suffering from stroke and a possible greater risk of heart disease, according to Dr David Kernick, a GP at the Exeter Headache Clinic in St Thomas.
Writing in the British Journal of GPs in 2015, he argued statins should be prescribed to people who suffer the condition should be prescribed statins earlier than the rest of the population.
But other experts say more evidence is needed before a rule-change is needed.
Professor Peter Weissberg, consultant cardiologist at the Addenbrooke’s Hospital in Cambridge and medical director at the BHF, said it is possible heart attacks and strokes in people with migraines are caused by something different to the rest of the population.
He said: ‘We would need more evidence, from randomised clinical trials or case controlled studies, that prescribing statins for people with migraine would indeed bring about a reduction in heart attacks and strokes before changing guidelines.
‘This may be because the processes underlying heart attacks and strokes are different in migraine sufferers from the rest of the population, in which statins have been shown to be beneficial.’
Health chiefs began introducing safety warnings on statins stating they may cause a small increased risk of higher blood sugar levels and type 2 diabetes diagnosis.
Most research that has highlighted a potential link did not investigate the association specifically, focusing instead on heart problems more broadly.
A paper by the Albert Einstein College of Medicine in New York, published in the British Medical Journal in 2017, suggested people who are pre-diabetic — when blood sugar is higher than normal but not at diabetic levels — are 36 per cent more likely to develop the condition after taking statins.
It measured blood pressure, fats and glucose in more than 3,200 US adults over 10 years. At the start of the trial just 4 per cent were using statins, but this increased to more than a third by the end.
The study found those on statins were 32 to 37 per cent more likely to develop diabetes. But critics say the results do not show statins increase the risk of diabetes in people who are not prediabetic.
Sir Nilesh told MailOnline: ‘Several studies have established that statins can increase the risk of developing diabetes, especially in those who may be at risk for other reasons.
‘As diabetes is itself a risk factor for heart disease, this has raised a concern about whether developing diabetes would offset any benefits of statins.
‘However, the risk of developing diabetes is small, and for the vast majority of patients in whom statins are recommended, the benefits far outweigh the risks.
‘Existing guidelines on who should be recommended a statin reflect the risks of possible side-effects with the cardiovascular benefit to patients.’
Statins increase a patient’s blood sugar slightly but not enough to cause diabetes in people with normal levels in the first place.
Rather, the mild increase can lead to a diagnosis around five weeks earlier in people that are already borderline diabetic, according to Dr Seth Martin, a medic at John Hopkins University.
Finally, many statin users are warned not to eat grapefruit because of the fruit’s effect on how the body processes the drug.
Grapefruit contains chemicals called furanocoumarins which block an enzyme in the intestine that normally breaks down statins and some other drugs.
This means the statins build up in the bloodstream rather than being processed properly, which can increase the risk of other side effects.
But grapefruit only appears to have a large effect on certain statin medications, with others seeing little to no problems.
Atorvastatin, sold as Lipitor, lovastatin, sold as Mevacor, and simvastatin, sold as Zocor, are the only drugs known be particularly affected by the chemicals, according to Dr Jorge Plutzky, an associate professor of medicine at Harvard Medical School.
In contrast, there appears to be no interaction in people taking fluvastatin (Lescol), pitavastatin (Livalo) pravastatin (Pravachol) and rosuvastatin (Crestor).
Sir Nilesh said: ‘If you take simvastatin, you shouldn’t drink grapefruit juice as it increases the concentration of the drug in the blood stream, increasing the risk of side effects.
‘If you take another type of statin, limit your intake of grapefruit juice to very small quantities or you may want to avoid it altogether.’