Bone scan reveals late-life dementia risk

An international research team has shown a simple and common scan can reveal if people are at increased risk of developing late-life dementia, which is becoming increasingly common after 80 years of age and develops when brain cells are damaged from several diseases — some of which cause narrowing of the blood vessels to the brain.

The researchers discovered an important link between vascular health and late-life dementia: the calcification of the plaques that can build up within the abdominal aorta, which is the largest artery in the body and supplies oxygenated blood from the heart to the abdominal organs and lower limbs. This calcium build-up — known as “abdominal aortic calcification”, or AAC — can be used to predict cardiovascular disease risk such as heart attack and stroke, but was also found to be a reliable marker for late-life dementia.

Led by Edith Cowan University (ECU), the research team examined the AAC results in 968 women from the late 1990s, and then followed their health status for over 15 years. Their results, published in The Lancet Regional Health – Western Pacific, found one in two older women had medium to high levels of AAC, and these women were twice as likely to be hospitalised or die from a late-life dementia, independent of other cardiovascular factors or genetic factors.

Professor Simon Laws, the Director of ECU’s Centre for Precision Health, said AAC could identify dementia risk earlier in life. He said, “AAC is important as it was able to identify dementia risk in people who don’t have the major genetic risk factor present in 50% of people who develop Alzheimer’s disease, which is the most common form of dementia.”

Conveniently, AAC can be easily detected using lateral spine scans from bone density machines. These machines are common, with some 600,000 bone density tests performed each year in Australia to screen for osteoporosis, so it should be feasible for an additional scan capturing lateral spine images to be performed when people undergo their usual tests.

“It’s generally very quick and easy to capture these scans, and they are less invasive, cheaper and miniscule in radiation exposure compared to X-rays or CT scans,” said ECU Associate Professor Joshua Lewis.

“We know the causes of AAC go beyond traditional cardiovascular risk factors and many of these causes overlap with late-life dementia risk factors.

“At ECU we’re also working with the computer science team automating the AAC assessments, which will make the process a lot quicker and easier rather than needing a trained imaging expert to read the scans.

“It means these scans may be a cheap, rapid and safe way to screen a large number of susceptible older Australians for higher late-life dementia risk.”

Lewis said incorporating dementia risk into discussions surrounding cardiovascular health could see people make necessary lifestyle changes, stating, “I think the next step is telling people about their AAC and late-life dementia risk to see if this can motivate healthy diet and lifestyle behaviour changes.”

“What’s come to light is the importance of modifying risk factors such as diet and physical activity in preventing dementia,” Laws concluded. “You need to intervene early, and hopefully this study allows for the earliest possible change and the greatest impact.”

Image credit: ©stock.adobe.com/au/Sidekick

Please follow us and share on Twitter and Facebook. You can also subscribe for FREE to our weekly newsletters and bimonthly magazine.