Cholesterol-busting drugs have been linked to reducing the risk of dementia by up to 13% for some people, according to a new study. Statins are one of the most commonly prescribed drugs in the UK, with about seven to eight million people taking them to cut their chance of heart attack and stroke. New research suggests they may have more benefits.

Experts found people with low levels of "bad" cholesterol in their blood have a reduced risk of dementia, including Alzheimer's disease. Use of statins was found to have "additional protective effects", according to the study.

Statins are a group of medicines which can help lower the level of low-density lipoprotein (LDL) cholesterol in the blood. LDL cholesterol (LDL- C) is often referred to as "bad cholesterol". It can cause plaque to build in arteries, leading to cardiovascular disease, which can increase the chance of strokes, heart attacks and death.

Researchers in South Korea said their findings "underscore the crucial role of managing LDL- C in lowering dementia risk". The experts examined health data on more than 570,000 people in the Asian country.

The NHS says people should aim for "bad cholesterol" levels in the blood to be below 4mmol/L (millimoles per litre).

Study experts found people whose LDL cholesterol levels were below 1.8 mmol/L had a 26% reduced risk of dementia and a 28% reduced risk in Alzheimer's compared to those who have LDL cholesterol levels above 3.4 mmol/L.

Statin use appeared to provide extra protection against dementia in the presence of low LDL cholesterol levels.

Among people with LDL cholesterol levels below 1.8 mmol/L, statin use was linked to a 13% reduction in dementia risk and a 12% decrease in risk of Alzheimer's disease compared with non-users.

The study authors wrote in the Journal of Neurology Neurosurgery and Psychiatry: "These findings emphasise the importance of targeted LDL- C management as part of dementia prevention strategies, with potential integration into clinical guidelines.

"The results support the use of statin therapy within specific LDL-C ranges for both cardiovascular and cognitive health benefits."

They added: "This insightful understanding of how statin use interacts with LDL- C levels emphasises the need for personalised statin prescriptions, focusing on achieving LDL- C levels that offer the maximum cognitive benefits."

Dr Julia Dudley, Head of Research at Alzheimer's Research UK, said: "This large study looked at patient records for levels of LDL cholesterol and the risk of dementia, it also examined those patients who were on statins.

"It found that those people with lower LDL levels had a reduced risk of dementia. The use of statins seemed to offer a protective effect - even in those who already had cholesterol levels within a lower range.

"However, dementia risk is complex and influenced by many factors. 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. Clinical trials will be key to understand what effects statins might be having on disease processes in the brain.

"In the meantime, keeping our hearts healthy remains one of the most effective ways we can protect our brain health. If you have any concerns about your cholesterol levels, you should speak to your GP."

Dr Richard Oakley from the Alzheimer's Society, added: "Dementia risk is complicated and determined by several factors including genetics, lifestyle, and the environment.

"This study adds to our understanding by showing the strong connection between heart and brain health. Simply put, what is good for the heart is good for the head."

He added: "This is an ever-evolving topic, and more targeted research and trials are needed to understand whether statins can help protect the brain. However, it is crucial to talk to your GP before making any changes to your medication."