A Facebook post makes a number of claims about cholesterol and statins (medications which can help lower cholesterol).
The post lays out a number of theories and mechanisms for cholesterol function in the body, and argues these mean that medical treatments wouldn’t work. We have not gone into these theories in detail.
We have however fact checked claims about the efficacy of medical interventions mentioned in the post and found it makes false and misleading claims about the benefits of procedures used to treat heart disease and statins.
Honesty in public debate matters
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Cholesterol is essential and is used to make cells and produce hormones among other tasks. We can produce cholesterol from other fats, or consume it directly in our diet.
Cholesterol is measured in the blood in a number of ways–total cholesterol, LDL-cholesterol and HDL-cholesterol. LDL is generally thought to be “bad cholesterol” and HDL as “good”. LDL deposits cholesterol into artery linings, whereas HDL can carry cholesterol to the liver for metabolism and clearance from the body.
The main risk of high cholesterol is from plaques–a buildup of cholesterol and other substances in the lining of blood vessels. These can make the vessels narrower causing problems with blood flow. If these plaques burst, they can cause clots in the vessel which lead to heart attacks or strokes (when the blood flow to the heart and brain respectively are cut off or severely restricted).
People who are obese or eat fatty diets generally have increased cholesterol levels.
Consensus opinion has been for decades that high cholesterol, especially LDL, increases the risk of heart disease and strokes.
Stents and angioplasties
The post claims that stents and angioplasty “have not been shown to reduce heart attack risks or save lives”. This is false.
Angioplasty refers to using a balloon to widen a narrowed artery. Stents are small plastic tubes placed into arteries to hold them open. Use of these methods together to treat patients with blocked coronary arteries is usually called percutaneous coronary intervention (PCI).
The evidence shows that angioplasty with stents reduces the risk of death and future heart attacks in patients with specific forms of heart disease. Angioplasty for patients having STEMIs (heart attacks involving total blockage of the arteries) has particularly significant benefits.
There is some evidence newer drug-releasing stents can improve the benefits of stents for patients with acute coronary syndromes (a general term for when blood to the heart muscle is blocked causing damage). It is standard practice to offer PCI as a first treatment for these patients.
In 2020/21 68% of PCI procedures performed in the UK were for acute coronary syndromes . In 2016, 92% of PCIs used stents.
Patients with ‘stable’ heart disease (where a patient has transient episodes of chest pain as a result of not getting enough blood and oxygen to the heart muscle) may be offered PCI, but evidence trends seem to show that this doesn’t improve rates of heart attack or death compared to medication and lifestyle modification alone (although PCI can provide relief of symptoms and improve quality of life).
However, given the evidence of the benefit of PCI for people having STEMI heart attacks, it is misleading to claim “angioplasty, and [...] stents, have not been shown to reduce heart attack risks or save lives”.
The post then goes on to claim that “statin drugs for high cholesterol can not reduce heart attack risks […] they do not unblock arteries, nor stop blocked arteries from forming”. It also references “the mental and cognitive decline in statin users” and claims that “the lower your cholesterol the shorter your life span and the higher your risk for dementia and Alzheimer's”.
For decades, statins have been used to reduce the risks of high cholesterol. Statins reduce LDL-cholesterol levels chiefly by reducing its production in the liver.
A Cochrane Review, often considered the highest quality form of evidence in medicine, analysed the data from 18 randomised controlled trials.
It found that all-cause mortality, fatal and non-fatal cardiovascular disease (CVD) events and need for artery bypass grafting or PCI (indicators of newly blocked arteries) were all significantly reduced among people without, but at risk of, cardiovascular disease, by using statins.
For every 1,000 people placed on statins for five years, 18 major CVD events (including heart attacks and strokes) were prevented.
Another meta-analysis of studies including patients who underwent ultrasound scans of their arteries before and after taking statins found significant reduction in the size of plaques.
As for the link between statins, cholesterol and cognitive function, the evidence is mixed, with some studies showing improvements and others showing decline.
A large observational study found that younger statin users saw reductions in cognitive ability while older statin users saw improvements. Another study found no evidence that statins affect Alzheimer's risk.
Another found an association between higher LDL-cholesterol in mid-life and a higher risk of dementia. This might suggest statins, which reduce the production of LDL-cholesterol, may be associated with a lower risk of dementia.
The picture is not completely clear and is complicated by the fact that people who are given statins often have other conditions increasing their risk of cognitive decline or dementia like high blood pressure or diabetes.
A Cochrane Review using looking at two clinical trials (which in theory shouldn’t be affected by these sorts of biases) rather than observational data found no difference in dementia risk between groups taking statins and those not.
Dr Emma Anderson, Associate Professor at Division of Psychiatry, UCL, told Full Fact there is no “definitive answer” for the overall effect of cholesterol on Alzheimer’s risk, but that “evidence to date points to there being an adverse effect of higher total or LDL cholesterol on dementia risk. [...] A smaller number of studies have found no evidence of any effect. I am not aware of any robust peer reviewed research showing [Alzheimer’s] is increased by lower cholesterol.”
Image courtesy of www.scientificanimations.com