Simple cholesterol checks can help predict dementia up to six years before diagnosis, promising research suggests today.
Previous studies have long linked having high cholesterol in middle age to a higher risk of developing the memory-robbing disorder.
But now scientists in Australia, who followed almost 10,000 adults in their 70s, found that people with stable levels had a ‘significantly’ lower chance of being diagnosed or showing cognitive decline.
Experts hope that routine cholesterol checks can now be used to flag people with fluctuating cholesterol levels, so patients can be treated earlier.
But the researchers, who labeled the findings as ‘important’, did acknowledge that the paper was only observational and could not prove why fluctuating numbers might increase the risk of the condition.
Lead author of the study and expert in chronic disease and aging at Monash University in Melbourne, Dr Zhen Zhou, said: ‘Older people with fluctuating cholesterol levels unrelated to the use of lipid-lowering drugs may benefit from better monitoring and justify proactive preventive interventions.”
Professor Fernando Testai, an expert in neurology and rehabilitation at the University of Illinois at Chicago, added: ‘This study adds an important piece to the puzzle of maintaining brain health by providing evidence that increasing variability in cholesterol levels is associated with cognitive decline.
‘The study did not include people who started or stopped taking lipid-lowering medications during the study period.
But now scientists in Australia, who followed almost 10,000 adults in their 70s, found that people with stable levels had a ‘significantly’ lower chance of being diagnosed or showing cognitive decline.
Experts hope that routine cholesterol checks can now be used to flag people with fluctuating cholesterol levels, so patients can be treated earlier. Pictured: a cholesterol plaque in the artery
‘The results cannot therefore be explained by the effect of statins.
‘From a practical point of view, failure to adhere to strategies that improve the lipid profile, such as following a healthy diet and exercise, may worsen the negative impact of harmful lipids on the brain.’
In the study, researchers followed nearly 10,000 adults in their 70s who made no changes in taking cholesterol-lowering medications.
Over a six-year follow-up, they found that 509 participants developed dementia and another 1,760 developed cognitive decline without dementia.
Those with the highest fluctuations in cholesterol – who were in the top 25 percent – were 60 percent more likely to be diagnosed with dementia, the scientists said.
They also had a 23 percent higher risk of cognitive decline.
Volunteers with higher levels of low-density lipoprotein cholesterol – LDL cholesterol or “bad” cholesterol – were most likely to see significantly faster declines in scores on cognitive health tests and tests involving memory and reaction speed.
High-density lipoprotein cholesterol (HDL), meanwhile, has long been considered beneficial due to the abundance of evidence showing that it protects the heart.
Around 900,000 Britons are currently thought to suffer from memory theft disorder. But scientists at University College London estimate that this number will rise to 1.7 million within 20 years as people live longer. It represents an increase of 40 percent compared to the previous forecast in 2017
Alzheimer’s disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss
It removes cholesterol from the blood vessels and transports it to the liver where it is broken down and removed from the body, reducing the risk of heart attacks and strokes.
But since then, research has begun to challenge the traditional view that more is better when it comes to HDL levels.
Yet the scientists found that high fluctuations in HDL were not associated with dementia or cognitive decline.
However, the scientists acknowledged that the study had “some limitations,” including predominantly white adults (96 percent), meaning the results may not apply to other populations.
The findings will be presented in full at the American Heart Association’s 2024 Scientific Sessions in Chicago.
Cholesterol is a fatty, waxy substance found in the blood that is vital for body functions including digestion, making vitamin D and hormones.
However, too much can build up in the blood due to eating fatty foods, insufficient exercise, being overweight, smoking and drinking alcohol.
High LDL cholesterol does not cause any symptoms, but it can lead to clogged arteries and increase the risk of heart problems and stroke.
Meanwhile, HDL cholesterol has been shown to protect against heart disease, with the NHS stating that levels above 18 mg/dl for men and 21.6 mg/dl for women are healthy.
Recent analysis by the Alzheimer’s Society estimates that the total annual cost of dementia to Britain is £42 billion per year, with families bearing the brunt.
An aging population means these costs – including the lost income of unpaid caregivers – are expected to rise to £90 billion over the next fifteen years.
It is thought that around 944,000 people in Britain are living with dementia, while in the US the figure is around 7 million.
Alzheimer’s disease affects about six in ten people with dementia.
It is thought to be caused by a buildup of amyloid and tau in the brain, which clump together, and by plaques and tangles that make it harder for the brain to work properly.
Eventually, the brain struggles to cope with this damage and dementia symptoms develop.
Memory problems, thinking and reasoning problems, and language problems are common early symptoms of the condition, which then worsen over time.
An analysis by Alzheimer’s Research UK found that 74,261 people died from dementia in 2022, up from 69,178 a year earlier, making it the country’s biggest killer.