Simple cholesterol checks could help predict dementia up to six years before a diagnosis, promising research suggests today.
Previous studies have long linked high cholesterol in midlife to an increased risk of developing this memory-robbing disease.
But now scientists in Australia, who tracked nearly 10,000 adults aged 70, found that those with stable levels were “significantly” less likely to be diagnosed or show cognitive decline.
Experts hope that routine cholesterol checks can now be used to detect people with fluctuating levels and speed up detection rates, allowing patients to receive treatment sooner.
But the researchers, who called the findings “important,” acknowledged that the paper was purely observational and could not prove why fluctuating rates may increase the risk of the condition.
Lead author of the study and public health expert at Monash University in Melbourne, Zhen Zhou, said: “Older people with fluctuating cholesterol levels unrelated to whether they were taking lipid-lowering drugs may need closer monitoring and 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 preserving 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.
«Therefore, the results cannot be explained by the effect of statins.
“From a practical point of view, not following strategies that improve the lipid profile, such as following a healthy diet and exercising, can worsen the negative impact of harmful lipids on the brain.”
In the study, researchers followed nearly 10,000 adults aged 70 or older, none of whom made any changes in taking cholesterol-lowering medications.
During a six-year follow-up, they found that 509 participants developed dementia and another 1,760 developed cognitive impairment without dementia.
Those with the biggest fluctuations in cholesterol (ranking in the top 25 percent) were 60 percent more likely to have a dementia diagnosis, the scientists said.
They were also 23 percent more likely to suffer cognitive decline.
Volunteers with higher levels of low-density lipoprotein cholesterol (LDL cholesterol, or “bad” cholesterol) were more likely to see significantly faster declines in scores on cognitive health tests and on tests involving memory and the reaction speed.
Meanwhile, high-density lipoprotein (HDL) cholesterol has long been considered good because of the wealth of evidence showing it protects the heart.
It is currently believed that around 900,000 Britons suffer from this memory-robbing disorder. But scientists at University College London estimate this figure will rise to 1.7 million within two decades as people live longer. It marks a 40 percent increase from 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 arteries and carries it to the liver to be broken down and removed from the body, reducing the risk of heart attacks and strokes.
But since then some research has begun to challenge the traditional view that more is better when it comes to HDL levels.
However, the scientists found that high fluctuations in HDL were not associated with dementia or cognitive decline.
The scientists, however, acknowledged that the research had “some limitations,” including the participation of predominantly white adults (96 percent), meaning the results may not apply to other population groups.
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 bodily functions, including digestion, the production of vitamin D and hormones.
However, too much can accumulate in the blood due to the consumption of fatty foods, lack of exercise, being overweight, smoking and alcohol consumption.
Having high LDL cholesterol does not trigger any symptoms, but it can cause clogged blood vessels 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.
A recent analysis by the Alzheimer’s Society estimates that the total annual cost of dementia in the UK is £42 billion a year, with families hardest hit.
An aging population means these costs – which include lost income from unpaid carers – will soar to £90 billion over the next 15 years.
Around 944,000 people in the UK are thought to be living with dementia, while in the US the figure is around 7 million.
Alzheimer’s affects approximately six in 10 people with dementia.
It is believed to be caused by a buildup of amyloid and tau in the brain, which build up and build up of plaques and tangles that make it difficult for the brain to function properly.
Over time, the brain struggles to cope with this damage and symptoms of dementia develop.
Memory problems, thinking and reasoning difficulties, and language problems are common early symptoms of the condition, which then worsen over time.
Analysis by Alzheimer’s Research UK found that 74,261 people died from dementia in 2022, compared to 69,178 the previous year, making it the leading cause of death in the country.