If you find out you’re at high risk of Alzheimer’s, what can you do?

A new blood test for Alzheimer’s which can detect signs of the disease up to 15 years before symptoms appear could be used to screen people over 50.

With cases of dementia, of which Alzheimer’s is the most common form, predicted to hit 1.6 million by 2040, the news has been hailed as a major step forward by experts around the UK. 

The test measures levels of a protein in the blood called p-tau217 which reflects the accumulation of toxic tau tangles in the brain, which ultimately lead to symptoms such as memory loss, confusion and personality change.

When the test was assessed by Swedish neuroscientists at the University of Gothenburg using data from 786 individuals, it was found to be just as predictive as far more expensive and invasive methods which are not routinely available.

“In current practice, the only way to prove that someone has a build-up of these proteins in the brain is to have a lumbar puncture or an amyloid PET scan, which are only available in about one in 20 NHS memory clinics,” says Charles Marshall, professor of clinical neurology at Queen Mary University of London. “The hope is that blood tests like this will improve access to a diagnosis and ultimately ensure that people can benefit from emerging treatments that can slow the progression of Alzheimer’s disease.”

Professor Jonathan Schott of the UCL Institute of Neurology described the findings as “hugely exciting”, although he cautioned that the test will need to be studied in real-life memory clinics and diverse populations across the UK. 

So how could this change the landscape of Alzheimer’s treatment in future?

New drug treatments

Schott suggests that the most immediate applications of such a test could be in screening participants for clinical trials of future drugs which aim to reduce the impact of Alzheimer’s. 

Right now, the main class of drugs available to Alzheimer’s patients on the NHS are called acetylcholinesterase (AChE) inhibitors which provide some mild symptom relief, but do nothing to stop the disease progressing. “These drugs do not address underlying pathologies within the brain that we think cause Alzheimer’s disease,” says Schott.

However, far better therapies are already within reach. UK regulators are currently assessing two antibody therapies, lecanemab and donanemab, which actively clear toxic proteins from the brain. Both drugs made headlines last summer after clinical trials which showed they could slow cognitive decline in patients presenting with early symptoms of the disease, and have already been green-lit by regulators in the US and Japan.    

In the coming years, the new test could be used to identify patients at high-risk of Alzheimer’s and conduct clinical trials to see whether either lecanemab or donanemab can actually prevent the onset of the disease.

Another area of interest is whether certain lifestyle changes can be shown to alter the disease process in people found to be at a high-risk of developing Alzheimer’s or other forms of dementia. 

What can increase a person’s chances of getting dementia?

In 2020, The Lancet estimated that about 40 per cent of all dementia cases are preventable through making appropriate lifestyle choices, such as avoiding excessive alcohol use in midlife, staying active and avoiding obesity or diabetes through following a healthy diet.

About 10 per cent of all early-onset dementia cases are linked to alcohol. Regularly consuming more than 21 units of alcohol per week can prove toxic to neurons and blood vessels within the brain, resulting in alcohol-related brain damage.  

A diet high in ultra-processed foods can also be a significant cause. According to a 2022 study in the Journal of the American Medical Association, obesity is now the leading modifiable risk factor for dementia in the US. One of the reasons for this is because it can lead to high blood pressure, damaging the fragile blood vessels in the brain.

Loneliness and social isolation are also thought to be damaging factors for brain health. In 2022, a study in the journal Neurology found that 60- to 79-year-olds who were lonely were three times more likely to develop dementia. This is thought to be because lack of social engagement leads the brain to shrink in size at a much greater rate than normal, affecting the ability to plan and remember instructions.  
“It’s incredibly important to stay socially connected,” says Barbara Sahakian, a professor of clinical neuropsychology at the University of Cambridge. “You have to drive the neural networks in the brain to keep them active through conversation and stimulation. That also reduces stress, which can damage the brain.”

The habits that can reduce your risk of Alzheimer’s and other dementias

Other lifestyle changes can protect us. Last year UCL researchers showed that short daytime naps could help preserve brain health in old age by slowing the rate at which our brains shrink. 

Published in the journal Sleep Health, the study gathered data from 378,932 people aged 40-69, and found that those genetically predisposed to napping had larger brain volumes, equivalent to reversing between two and six years of ageing. Previous research indicates that naps of 30 minutes or less are best, as they help replenish the brain without disrupting the normal sleep cycle. Victoria Garfield, a research associate in genetic epidemiology at UCL who led the study, says that the findings illustrate the importance of sleep when it comes to protecting the brain.

“Getting between seven and eight and a half hours a night is the sweet spot for adults in mid to late life,” says Garfield. “We showed in another study, several years ago, that there could be a causal relationship between sufficient sleep and things such as processing speed, reaction time and visual memory. This new research shows that regular naps might help halt the brain shrinking, which occurs with age, especially if the sleep at night isn’t of great quality or duration.”

But it isn’t just about power naps, Garfield says that one of the simplest things you can do to try to preserve your brain health is to focus on sleep regularity. This involves going to bed at roughly the same time each night. For while a lot of us stay up later on a weekend, before trying to slip back into a normal sleeping routine during the week, even these little disruptions are unsettling for the brain.

“What we like about this is that it’s an easier public-health message when it comes to dementia prevention than losing weight or going to the gym,” says Garfield. “It’s free, and you can do it by using a sleep diary or looking at your sleep on a wearable device.”

Exercise and purpose

Researchers studying groups of individuals who have lived unusually long lives, for example supercentenarians who live past 110, have found that age-related cognitive decline is far from inevitable, and, in fact, you can keep yourself mentally young by retaining a purpose in later life.

For example, people who keep working throughout their 50s and 60s are thought to be more resilient to cognitive decline than those who retire early. Continuing to work part-time or volunteering into your seventh, eighth and ninth decades can maintain what neuroscientists call your “cognitive reserve”. “Purpose is increasingly associated with maintaining brain function,” says Joyce Shaffer, a psychologist and behavioural scientist at the University of Washington, in Seattle. “The more you continue to do in your 50s, 60s and 70s, the more reserve you have for later on in life.”

Learning a new musical instrument, or returning to one you played as a child, is thought to be particularly stimulating for the brain. In June last year, a study of adults in their 60s and 70s who received six months of weekly piano lessons showed that there was an increase in the volume of the cerebellum, the part of the brain that helps with memory storage and decision-making.

“We’ve seen that music training can improve retention of words, verbal fluency in conversations and processing speed, which you need to make quick decisions, for example when you’re driving,” says Jennifer Bugos, associate professor of music education at the University of South Florida.

Any form of regular exercise is also another proven way of staving off cognitive decline. While brain size naturally decreases at a rate of about 5 per cent a decade after the age of 40, with the rate of decline increasing once you pass 70, research has shown that this shrinkage slows in those who do regular aerobic exercise. This includes any physical activity that gets the blood pumping, such as brisk walking, running, swimming and biking.

Working to increase your muscle mass in the gym is also more important as you get older, and not just because it prevents frailty and falls. Research from the University of California, San Francisco, has shown that having higher levels of lean muscle has a protective effect against Alzheimer’s, too. Using data from 450,243 people in a database called the UK Biobank, individuals with higher lean muscle mass were found to have a 12 per cent lower risk of Alzheimer’s disease.

“It’s thought that the reason the brain volume is maintained is because there’s an increased rate of production of new brain cells within moments of doing aerobic exercise,” says Shaffer. “But strength training, where you’re working your muscles, is also important for your brain, and that can lead to the production of new brain cells even days later. Both forms of exercise are important.”

What is the latest cutting-edge research or treatment for dementia?

As well as lecanemab and donanemab, research is ongoing into other medications for the disease, using information that has been found in genetic studies of Alzheimer’s and other types of dementia.

In April 2022, a study was published in the journal Nature Genetics that identified 75 genes associated with Alzheimer’s. Some were linked to how people process lipids in the brain to a part of the immune system called the complement system, which can start to malfunction and begin mistakenly killing off the synapses that connect cells in the brain.

Professor Julie Williams predicts that this information could lead to new Alzheimer’s drugs in the years to come. “Genetics has changed our view of this disease in the past five to six years, in terms of influencing new directions for targeting Alzheimer’s,” she says.

There is one form of dementia that is currently curable, known as autoimmune dementia. In this case, the memory loss and confusion are a result of inflammation caused by rogue antibodies binding to the brain, rather than an underlying neurodegenerative disease. Over the past 10 years, neurologists have started to become more adept at identifying cases of autoimmune dementia, which typically progresses much faster than other dementias, with symptoms developing within weeks or months.

Once identified, patients can be treated, and in some cases completely cured through immunotherapy or a treatment called plasma exchange, which attempts to wash the blood of the disease-causing antibodies. “I think this is underrecognised by doctors,” says Eoin Flanagan, who researches autoimmune dementia at the Mayo Clinic. “When they see an elderly patient, there’s often a high suspicion for Alzheimer’s, which we don’t have a treatment for. But some patients can have an autoimmune cause, and it’s particularly vital to spot those ones, because they can be cured.”

What is the connection between hearing loss and dementia?

Hearing has long been connected to brain health from midlife onwards for reasons we are still attempting to understand. Various population studies have shown that dementia risk increases in parallel with the degree of hearing impairment, doubling for mild hearing loss, tripling for moderate hearing loss, and being almost five times greater for severe hearing loss.

There are three main theories for why this might be the case. Julia Sarant, an associate audiology professor at the Melbourne School of Health Sciences, says some scientists have speculated that the very same factors damaging the brain could also be affecting the cochlea, the spiral-shaped cavity in the inner ear that enables hearing. It has also been suggested that lack of stimulation to the auditory cortex – the part of the brain that processes sounds – caused by hearing loss causes it to shrink and slowly degenerate over time.

“Some people also think that difficulty understanding speech increases cognitive load, or the amount of work the brain needs to do to perceive speech,” says Sarant. “This means that the brain must divert resources away from other functions, such as working memory, meaning they start to perform more poorly.”

Some research has suggested that treating hearing loss, for example through hearing aids, could help improve cognition, possibly by enabling people to receive more auditory and environmental stimulation, making them less socially isolated. The findings are not conclusive, but Sarant says it is a practical step that can potentially improve your brain health.

“Consider trialling hearing aids as soon as you are told you have hearing loss,” she says. “It is likely this will protect your cognitive function and, when you are younger, your brain will adapt more easily to the auditory information hearing aids provide. You will be able to make the most of the technology and your brain function will be less impacted by your hearing loss, particularly if it is mild.”