Lowering levels of bad cholesterol could cut your risk of dementia by 26%, new study claims

Lowering your levels of bad cholesterol could significantly curb your risk of dementia, new research suggests.

Last year, an international panel of dementia experts said that high levels of low-density lipoprotein (LDL) cholesterol – commonly referred to as “bad” cholesterol – are a risk factor for dementia. 

But the new study, which included nearly 109,000 people, offers a clearer picture of exactly how strong that link is.

People with lower LDL cholesterol levels had a 26 per cent lower risk of dementia, and a 28 per cent lower risk of Alzheimer’s disease specifically, according to the study, which was published on Tuesday in the Journal of Neurology Neurosurgery & Psychiatry.

Taking statins, which help lower cholesterol and reduce the risk of heart attack and stroke, provided “additional protective effects,” the study found. 

People with low LDL cholesterol levels who took statins had a 13 per cent lower risk of dementia compared with those who did not take them.

There are two types of cholesterol: LDL cholesterol contributes to buildups of fatty deposits in the arteries, raising the risk of heart problems. Meanwhile high-density lipoprotein (HDL), which is often called “good” cholesterol, clears LDL cholesterol from the arteries and brings it back to the liver, where it can be broken down.

In the study, the reduction in dementia risk was most apparent for people with LDL cholesterol levels below 70 mg/dL. People with very low levels – below 30 mg/dL – did not see an added risk reduction.

The findings suggest that helping people manage their cholesterol could be an effective way to slow down or prevent dementia, according to the researchers from several universities in South Korea.

“The results give a convincing argument for researchers to consider LDL cholesterol in addition to the classic approaches,” Dr Francesco Tamagnini, a neurophysiologist at the University of Reading in the UK who was not involved with the study, said in a statement.

Search for answers on dementia continues

Dementia affects an estimated 57 million people worldwide, a number that is expected to triple by 2050. However, experts believe that about half of dementia cases could be delayed or prevented altogether.

To date, much dementia research has focused on abnormal amyloid beta plaques, which are build-ups of protein in the brain and characteristic of Alzheimer’s, the most common form of dementia.

“There is clearly more to the story of Alzheimer’s than we first thought,” Tamagnini said.

It’s too soon to say that LDL cholesterol actually causes dementia. The study has some limitations, including the fact that it tracked people’s health data retroactively, meaning other factors may have played a role in the link between lower LDL cholesterol levels and dementia risk.

“Dementia risk is complex and influenced by many factors,” Dr Julia Dudley, who leads research at Alzheimer’s Research UK, said in a statement.

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“Without a detailed picture of what’s going on in the brain we do not know if there is a direct link between lower cholesterol and reduced dementia risk,” she added.

The next step is for researchers to do clinical trials that test whether statins to lower LDL cholesterol could help slow the disease progression.

“In the meantime, keeping our hearts healthy remains one of the most effective ways we can protect our brain health,” Dudley said.