WE used to think that dementia was a cruel twist of fate. The condition was largely associated with malfunctioning genetics causing people’s brains to deteriorate drastically as they aged, leading to problems with memory, thinking, language, and the ability to carry out everyday tasks.
Science is now telling us otherwise. While genetics and other uncontrollable factors are still recognised as significant factors in why some people develop dementia, two major new research reviews show that lifestyle also has an important role to play.
A Lancet Medical Journal review identified key factors that contribute to dementia risk. Also, a review published in the Journal of Neurology, Neurosurgery, and Psychiatry analysed 395 studies on Alzheimer’s, the most common cause of dementia, and concluded that certain strategies could fend off the disease.
In 2018, an estimated 55,000 people were living with dementia in Ireland, and an extra 11,000 are diagnosed with the disease every year.
There is no cure for dementia nor drugs available to stall its progress. As a result, dementia is now the second-highest cause of death in Ireland.
“There is no disease-modifying treatment available for dementia, so it is reassuring that the authors of the Lancet review state that the potential for prevention is high,” says Dr Carol Rogan, scientific project manager for Dementia Research Network Ireland. “It is never too early or too late to make changes to our lifestyles and behaviours in order to prevent dementia.”
Brian Lawlor, professor of old age psychiatry in Trinity College Dublin, believes that the evidence in both reviews is robust. “Their recommendations are based on observation and epidemiological data,” he says. “There is the potential to delay onset and to prevent dementia.”
So what are the recommended strategies and what power do we have to determine our fate as we age?
The Lancet review found that having a body mass index (BMI) higher than 30 increased an individual’s risk of dementia by 60%. This could be because body fat releases chemicals that cause a build-up of amyloid-beta proteins in the brain. This protein is associated with Alzheimer’s and other chronic diseases such as hypertension and cardiovascular disease that increase the risk of Alzheimer’s.
“A high BMI is also linked with lower levels of exercise, which may contribute to the risk,” says Prof Lawlor.
Being underweight is another risk factor. According to the review published in the Journal of Neurology, Neurosurgery, and Psychiatry, muscle loss in later life can lead to elevated levels of inflammation in the body and accelerate age-related cell damage in the brain. It can also reduce energy metabolism, which means there is less fuel for the brain.
Maintaining a BMI between 18.5 and 24.9 is the best way to avoid either of these outcomes.
If you needed yet another reason to move your body, the Lancet review found that inactive people were 40% more likely to develop dementia.
According to the Lancet review, people with type-2 diabetes have a 50% higher risk of dementia. Considering that the HSE estimates there are at least 160,000 people in Ireland with type-2 diabetes, that puts a lot of people at risk.
Eating a balanced diet and exercising regularly has been proven to minimise your chances of developing diabetes.
The Lancet researchers found that a blood pressure reading over 140mgHH increased an individual’s risk of dementia by 60%. “Over time, high blood pressure narrows the blood vessels and lowers the blood supply to the brain, increasing the risk of dementia,” says Prof Lawlor.
Diet and exercise can help with this, especially if you cut back on salt, caffeine, and alcohol.
Do you often feel dizzy when you stand up? This could be due to low blood pressure, which means the body is unable to maintain sufficient blood supply to the brain. “This decreased blood supply can lead to cognitive decline over time,” says Prof Lawlor.
Discuss this with your GP as there is medication that can help.
Numerous studies show that people with Alzheimer’s have high levels of homocysteine in their brains. This is an amino acid produced by the breakdown of protein and too much of it reduces the number of antioxidants in the brain. These antioxidants protect brain cells and the brain will deteriorate if there are too few of them.
The solution may be simple. A study in the American Journal of Clinical Nutrition in 2003 proved that supplements of folate and vitamin B12 can lower homocysteine levels.
A study carried out by researchers at Rush University in Chicago in 2007 found that people who keep their brains active had a lower risk of developing dementia.
“Mental stimulation increases nerve cell connectivity, which is what is broken in dementia,” says Prof Lawlor. “Stimulation may therefore protect you from cognitive decline.”
The Lancet review concluded that brain injury increased an individual’s risk of dementia by 80%. This is why we should all wear helmets when we cycle or play contact sports.
It’s not known if depression is a cause or symptom of dementia, but according to the Lancet review, depression increases the risk of dementia by 90%. “This shows how important it is to monitor older people with depression from a cognitive point of view,” says Prof Lawlor.
“The Lancet review suggests 4% of dementia cases could be attributed to social isolation in later life,” says Dr Rogan. “It recommends that national policies should encourage social activity throughout life for everyone.”
In 2010, researchers at Cambridge University found that the more education you had, the heavier your brain. Seeing as people with dementia lose as much as a third of their brain weight, education may make you more resilient to the disease.
Hearing loss in midlife accounts for 8% of dementia cases, according to the Lancet review. “This is based on a review of evidence that includes an Irish study by Loughrey in 2018 that found age-related hearing loss was associated with cognitive impairment and dementia,” says Dr Rogan.
Hearing aids can help minimise this risk.
Studies such as the CAIDE 30-Year Study, which was published in 2017, have shown that middle-aged people with high levels of stress have an increased incidence of dementia.
“While it is impossible to avoid stress completely, stress management and meditation can be helpful,” says Prof Lawlor.
Drinking more than 21 units of alcohol a week was found to increase the risk of dementia by 20%. As a guideline, a small glass of wine contains about 1.5 units, while a bottle of wine contains 10 units. A can of lager, beer, or cider is two units.
If you need yet another reason to quit, here is one: Smoking increases the risk of dementia by 60%.
The Lancet review found that people who live near main roads were 10% more vulnerable to neurological decline and dementia.
The study reviews from the Lancet and the Journal of Neurology, Neurosurgery, and Psychiatry “summarise the best available evidence from many scientific sources worldwide,” says Dr Rogan. By following these 15 steps, we could improve the health of our brain for the long term.