Statins could reduce dementia risk even if you have low cholesterol

Telegraph

01-04-2025

Statins can reduce the risk of dementia among those who already have low cholesterol, a study has suggested.
People taking the cholesterol-busting drugs were less likely to develop dementia, including Alzheimer's disease, even if they already had their cholesterol under control, experts found.
The research, published in the BMJ's Journal of Neurology, Neurosurgery and Psychiatry, found that people with healthy levels of 'bad' cholesterol in their blood were at reduced risk of the neurological condition compared to those with high levels.
But they also found that the risk of dementia reduced further among people who already had low cholesterol and were taking statins compared to those who were not, suggesting the drugs provide 'additional protective effects'.
While statins are usually prescribed to people in their 60s or 70s, the findings raise the prospect they could be given to younger people with normal levels of cholesterol as a way of protecting the health of both their heart and brain.
The researchers said the drugs were providing a 'synergistic effect' and could have a much bigger role to play in brain and cognitive health than previously thought.
Statins are one of the most commonly prescribed drugs in the UK, with around seven to eight million people taking the cheap, daily pills to cut their chance of heart attack and stroke.
'More to Alzheimer's than we first thought'
The medicine can help lower the level of low-density lipoprotein (LDL) cholesterol in the blood, often referred to as the 'bad cholesterol' because it can lead to plaque build-up in arteries and increase the chance of strokes, heart attacks and heart disease.
Researchers from South Korea, led by Hallym University and Kangdong Sacred Heart Hospital in Seoul, said their findings 'underscore the crucial role of managing LDL- C in lowering dementia risk'.
They examined health data on more than 570,000 people aged 18 and older in South Korea.
The NHS says that people should aim for bad cholesterol levels in the blood to be below 4mmol/L (millimoles per litre).
Researchers found that people with low LDL cholesterol levels below 1.8 mmol/L were 26 per cent less likely to develop dementia and 28 per cent less likely to develop Alzheimer's. This was compared to those with levels above 3.4 mmol/L - the higher end of a healthy range.
Taking statins saw those with LDL cholesterol levels below 1.8 mmol/L reduce their dementia risk by a further 13 per cent and 12 per cent for Alzheimer's compared with people who do not take them.
'These findings emphasise the importance of targeted LDL- C management as part of dementia prevention strategies, with potential integration into clinical guidelines,' the authors wrote in the Journal of Neurology Neurosurgery and Psychiatry.
'The results support the use of statin therapy within specific LDL- C ranges for both cardiovascular and cognitive health benefits.'
The study found the benefits of statins tailed off among people whose LDL cholesterol levels were 'very low' and had fallen below 0.8 mmol/L, suggesting a threshold with 'optimal benefit' that should be targeted and personalised to individuals.
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 Francesco Tamagnini, neurophysiologist at the University of Reading, said there was 'clearly more to the story of Alzheimer's than we first thought.'
'The results give a convincing argument for researchers to consider LDL cholesterol in addition to the classic approaches,' he said, hypothesising 'that damage to the blood-brain barrier can lead to accumulation of LDL cholesterol in the brain and potentially alter the electrical activity of neurons.'
He said proteins, amyloid and tau, had been widely considered as the 'main cause of Alzheimer's but that is an opinion that is now likely to fade.'
He added: 'Alzheimer's disease may be a complication caused by the accumulation of LDL in the brain. What we now need to find out is exactly how the high levels of lipids in the blood are causing Alzheimer's and other types of dementia.'
Dr Julia Dudley, head of research at Alzheimer's Research UK, said the results suggested '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,' she said.
She added that trials would be 'key to understand what effects statins might be having on disease processes in the brain.'
Almost one million people in the UK are living with dementia – a figure which is expected to rise by about 50 per cent over the next 15 years.