Cholesterol and the risk of dementia
Research suggests that high cholesterol is linked to increased risks of dementia. Statins may help reduce the risk.
Can high cholesterol increase the risk of dementia?
There is a relationship between a person having high cholesterol levels and going on to develop dementia.
People with high cholesterol levels also often have other health conditions like high blood pressure, diabetes or obesity, which are themselves risk factors for dementia. Separating these factors in terms of dementia risk is complex.
How to reduce the risk of dementia
A lifelong approach to good health is the best way to lower your risk of dementia.
There are some lifestyle behaviours with enough evidence to show that changing them will reduce your risk of dementia.
About cholesterol
Cholesterol is a fatty substance that is found in every cell in your body and has many roles. It forms part of the outer layer of every cell, helps keeps bones, muscle, skin and teeth healthy, and also helps nerves work properly.
Cholesterol is transported in the bloodstream. Its levels can be measured by a doctor. Our bodies make cholesterol naturally and we can also get it from certain foods.
There are good and bad types of cholesterol. The bad cholesterol (known as low density lipoprotein) leads to a build up of cholesterol in your arteries. This can increase the risk of stroke and cause more proteins to build up in the brain. Studies found that increases in bad cholesterol increases dementia risk.
Can statins reduce dementia risk?
Statins are drugs that are used to reduce the levels of cholesterol in the blood. Many people also take statins to reduce their risk of heart attacks and strokes. There have been many studies that have looked to see if this appears to alter the risk of dementia compared to people with untreated high cholesterol. Analysis combining 36 studies showed that statins reduced the risk of developing dementia by about 20%.
Looking at specific diseases, statins reduced the risk of Alzheimer’s disease by about 30% and reduced the risk of vascular dementia by about 7%.
The relationship between statins and dementia is complex.
Studies testing whether taking statins in later life to reduce dementia risk or improve memory and thinking skills have found no effect. However, it is through that sustained statin use, and the benefits for the heart and blood vessels, that satins can help.
In the past, there have been concerns that short-term use of statins caused memory loss and confusion in a small number of people. For these people, symptoms stopped after stopping the medication. This would suggest that the memory loss is not related to dementia, which would continue to get worse.
Cholesterol in the brain is important for the health of brain cells, and this may be affected in dementia. The gene that most affects the risk of late-onset Alzheimer's disease, ApoE4, plays a role in the processing and use of cholesterol.
Understanding this may lead to clues about the changes in the brain that cause dementia. Especially as changes in cholesterol processing in the brain may not be related to the levels of cholesterol in the blood.
However, cholesterol from the blood cannot enter the brain. The brain does use cholesterol, but it makes it ‘in-house’. So how blood cholesterol influences cholesterol in the brain and how this relates to dementia risk is yet to be understood.
Further reading
Alzheimer's Society dementia support line
Call 0333 150 3456.
If you are affected by dementia, worried about a diagnosis or a carer, trained staff are ready to give you the support you need. Opening hours (excluding bank holidays): Mon to Weds: 9am – 8pm, Thurs and Fri: 9am – 5pm, Sat and Sun: 10am – 4pm.
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