Can statins lower dementia risk?

If dementia has affected your family, you might have noticed recent UK headlines suggesting that statins could lower the risk of developing the condition. But how reliable are these claims? 

Statins are medicines designed to lower cholesterol that helps cut the risk of having a heart attack or stroke. More than 5.3 million people in England are prescribed them.  

The drugs work by lowering ‘bad’ cholesterol – which includes LDL cholesterol – in your blood. According to clinical guidelines in the UK, these levels should be below 3.0mmol/L if you have not had a heart attack or stroke, and below 2.0 mmol/L if you have had a heart attack or stroke. 

So, when new research was released in early April that suggested low LDL cholesterol levels might also cut the chances of developing dementia, and that statins may have an added benefit for brain health, the UK newspapers jumped on the story.

The study, published in the Journal of Neurology, Neurosurgery and Psychiatry, compared levels of LDL cholesterol in 217,960 people from South Korea and assessed their risk of developing dementia (all causes) and dementia related to Alzheimer’s disease. And then, in a secondary study they looked at whether taking statins had an impact on their dementia risk. 

To begin with, they divided those taking part into 3 sets depending on their LDL levels as follows:

• High LDL cholesterol: levels above 3.4 mmol/L 
• Healthy LDL cholesterol: levels below 1.8 mmol/L 
• Low LDL cholesterol: levels below 1.4 mmol/L 

Each group contained statin users and non-statin users to give a balanced overall result.

The researchers paired people with similar characteristics across the groups to compare their risk of dementia based on their LDL levels. 

They found having a healthy LDL cholesterol was linked to a 26 per cent lower chance of all-cause dementia and a 28 per cent lower chance of Alzheimer’s related dementia, compared to those with high LDL cholesterol levels. 

Is lower better when it comes to cholesterol? 

Does this suggest the lower our cholesterol levels the better when it comes to reducing risk of developing dementia or Alzheimer’s related dementia? Not necessarily. 

The researchers found low LDL cholesterol levels did not further reduce the risk of dementia or Alzheimer’s related dementia, with just an 18 per cent reduced risk compared to those in the high cholesterol group. 

This suggests there is a ‘sweet spot’ for LDL cholesterol levels, say the researchers. 

How do statins affect dementia risk? 

So, where do statins come in? Once they’d established dementia and Alzheimer’s risk based on the three cholesterol levels, the researchers compared statins users with non-statin users within each group. 

They found those with healthy LDL cholesterol levels who took statins were 13 per cent less likely to have dementia and 12 per cent less likely to have Alzheimer's related dementia, compared to those with the same LDL levels who did not take them.  

Those with high LDL cholesterol levels who took statins had a 7 per cent lower risk of all-cause dementia and a 10 per cent reduced risk of Alzheimer’s related dementia compared to those who did not take them.

For those with low LDL cholesterol, statins did not significantly reduce the dementia risk. 

This shows that taking statins to help reach healthy cholesterol levels may be as important for brain health as it is for heart health, according to the researchers. 

What do the researchers say?

They stress the study is observational. This means it can reveal possible links but does not show cause and effect.  

So, while the findings look promising, they advise against jumping to conclusions at this stage. 

However, the researchers also state that statins might have benefits for our brains that stretch beyond lowering cholesterol. Specifically, they could: improve the health of blood vessels in the brain, reduce inflammation in the brain, and help manage the build-up of a protein that’s linked to Alzheimer’s related dementia. 

How good is the research? 

This study stands out for its impressive scale – drawing on data from more than 200,000 individuals and is published in a highly respected journal.

However, it has some limitations. The researchers also only looked at LDL cholesterol levels at one point in time, so fluctuations over time were not considered.

The study also used past data, which might have missed some factors affecting the results, and relied on electronic health records, which might not always have been accurate.

Despite these limitations, the study still provides valuable information on how cholesterol levels might impact brain health, and the importance of making sure they are within the healthy range. 

How good was the media coverage? 

So, how accurate were the media’s claims?

Overall, the media did a good job of reporting on the study. Newspapers like The Independent and The Mirror gave a balanced view of the research and spoke to a variety of medical experts about the results.

However, many overstated the potential benefits of statins without exploring the limitations of the research.

The Daily Mail and the Express sensationalised the study with claims that were misleading.

Their headlines were ‘Statins slash dementia risk, even if you don’t have high cholesterol’ and ‘UK’s most prescribed drug 'can reduce dementia risk by 13%’, which do not reflect the full story. 

The BHF verdict

We already know statins play a crucial role in lowering LDL cholesterol levels and reducing the risk of heart disease.

This research suggests that keeping LDL levels moderately low might help lower dementia risk too -and that statins can help with this.

But while these findings are exciting, the evidence is not yet conclusive.  

It’s also important to note that statins alone would never guarantee protection against dementia. This is because there are many more risk factors for developing dementia than high cholesterol.  

These include high blood pressure, atrial fibrillation, smoking, drinking alcohol, and having an unhealthy diet.

Lifestyle changes can help reduce all these risk factors. These include swapping foods high in saturated fats, like fatty meats and full-fat dairy, for unsaturated fats found in vegetable oils, nuts, seeds, avocados and oily fish.

Replacing carbohydrates like white bread and pastries with wholegrain options. Adding more fibre to your diet by eating at least 5 portions of fruit and vegetables daily, incorporating pulses like lentils and beans, and choosing wholegrain foods.

Staying active by introducing simple activities like taking the stairs, brisk walking, or yoga to help your body get rid of bad cholesterol.

If you are worried you might have high cholesterol, speak to your GP or nurse.  

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