Scientists at the Heart Research Institute (HRI) have made a world-first breakthrough discovery, linking high cholesterol with an increased risk of dementia for the first time.
The research could see doctors soon be able to calculate a person’s risk of dementia by testing their cholesterol levels through an inexpensive and easy blood test.
The research led by HRI’s Dr Ashish Misra, Unit Leader of the Atherosclerosis and Vascular Remodelling team, analysed the data of 17 global studies, involving more than a million patients under the age of 65.
Dr Misra said the findings could be a game changer in reducing our risk of cognitive decline as well as improving our overall health.
“This is a really exciting discovery because we’ve found the association between cholesterol and dementia. Until now we haven’t known high cholesterol was a risk factor for dementia, but we’ve found a link: “bad” cholesterol aggregates a protein called tau between neurons, which cross the blood-brain barrier and can lead to dementia,”
Dr Misra said.
“This is the first time we’ve been able to say categorically that there’s a direct link between what we eat and our cognitive decline,” he said.
Cholesterol
is a type of fat (or lipid) that plays an important role in the body, helping
to make hormones, vitamin D, and substances that aid in digestion. However, too
much “bad” cholesterol from a high fat diet or dyslipidaemia, where there’s an
imbalance of lipid levels in the blood, can be deadly.
If there’s
too much cholesterol in the blood, the cholesterol can form plaques that collect
on the artery walls, causing them to become narrow and even blocking them,
reducing blood flow and increasing the risk of a stroke.
Experts say
once plaque develops on the arteries it is near impossible to dissolve
completely.
“Unfortunately,
there’s no magic drug to get rid of the plaque on your arteries. We need to
learn to live with it and help it dissolve over time through improved diet and
a healthy lifestyle.”
Dr Misra
said this discovery is not only about extending a person’s life but giving them
a better quality of life.
“Living longer is not important if you are not living healthy,” he said.
Up to 40 per
cent of a person’s dementia risk can be attributed to modifiable risk factors,
with evidence that the effects of dementia begin 10 to 20 years before clinical
symptoms emerge.
“Mild cognitive
impairment (MCI) is considered to be an ‘at-risk’ stage for dementia, with the
decline in cognitive function beyond what is expected for normal aging. More
than 50 per cent of MCI patients progress to dementia within five years.
“It’s
very exciting to know that if we can classify someone as high risk by checking
their blood work for high cholesterol in their 50s, then we can look at their
diet as a way of managing and even reducing their risk of dementia.
“Better
still, it’s a low-cost intervention. It’s checked with a blood test so it’s
easy to detect,” Dr
Misra said.
Dementia is
a neurodegenerative disease that causes the gradual impairment of brain
function, which could impact a person’s memory, speech, cognition (thought),
personality, behaviour and mobility.
The
Australian Institute of Health and Welfare estimates there were between
401,300 and 487,500 Australians living with dementia in 2022. That equates
to 15 Australians in every 1,000, and increases to 84 people with dementia per
1,000 for Australians aged 65 and over.
With an
ageing and growing population, that figure is projected to more than double by
2058 to 849,300 people.
“There is
substantial interest in identifying early to midlife interventions that may
prevent lifetime occurrence of dementia,” he said.
Dr Misra
said the next step is to find out how to reduce and treat the cholesterol
(lipids) and compare the results with a drop in cognitive decline.
Header image: Dr Ashish Misra
Media coverage
The Australian, 16 March 2023
