From social activity to blood pressure control, these 11 risk factors could prevent dementia. Photo / 123rf
A report has found that 14 factors are responsible for 45% of all dementia cases. Many are preventable with lifestyle changes.
We all know someone who has been struck with illness, such as a heart disorder, a joint problem or cancer, despite living a generally healthy lifestyle. But, as scientists unpick the factors that contribute to these conditions, we’re learning more about the specific tweaks we can make to help us dodge them.
A landmark report from some of the world’s top dementia experts found that 14 factors are responsible for 45% of all cases of the memory-robbing disease. If we could successfully tackle them, nearly half of cases would be prevented.
Not all of these factors are within an individual’s control – for example, quality of early life education, air pollution and traumatic brain injury are three of them – the other 11 contributors are and we can take action on.
“It’s never too early to start thinking about these things because factors in middle age have a big influence on what happens to our brains when we’re older,” says Terry Quinn, a professor of cardiovascular ageing at the University of Glasgow. “But it’s also never too late to begin thinking about them. Even if you wait until later in life, making some differences can change the risk you have of getting dementia.”
Seeing fewer people is a common problem with ageing, often a result of living alone or suffering illnesses that can put a limit on activities that were previously normal.
However, it can tip into social isolation – a dementia risk factor – if people see loved ones and friends very infrequently and aren’t in any groups or clubs.
“Social isolation can lead to cognitive decline due to reduced mental stimulation and a lack of social interactions that engage the brain,” explains Sandrine Thuret, a professor of neuroscience at King’s College London. “Isolation can also lead to depression and increased stress, which are risk factors for dementia.”
People who are socially isolated can reduce their risk through regular social activities, such as joining a club, volunteering, spending time with friends and family or adopting a pet, she suggests. Families and neighbours should make an effort to spend time with those who they think may be isolated, adds Quinn.
It’s worth noting that it hasn’t been proven that social isolation itself is a direct cause of dementia, though the research is pointing in that direction, Prof Quinn notes. Instead, it could be that the reasons a person became isolated – such as poor health – are to blame.
“I see so many people who think that hearing loss is a natural part of ageing and do nothing about it,” says Quinn. “As a result, they don’t engage with people or enjoy the things they did before – you can see why that would be bad for your brain health.”
While developing hearing loss doesn’t mean you’re doomed to develop dementia, leaving it untreated can increase the risk. This is because the reduction in hearing can decrease brain stimulation and contribute to social isolation and depression, explains Thuret. “Get regular hearing check-ups and use hearing aids if necessary. Protect your ears from loud noises and seek treatment for any hearing issues promptly.”
“There’s also a role for families and friends because if you notice that someone’s hearing is starting to go, you really need to encourage them to get the help that’s there,” Quinn adds.
Studies show that people who use hearing aids to manage their hearing loss reduce their risk of dementia to that of a person with normal hearing.
Depression – feeling persistently low for a long period of time to the point that it interferes with daily life – is a dementia risk factor, though the link is complicated.
“Depression can cause changes in the brain, including inflammation, reduced levels of certain neurotransmitters and a decrease in adult hippocampal neurogenesis,” which may provide a biological mechanism for how it harms the organ, says Thuret.
However, depression may also indirectly contribute to dementia by leading to a lack of motivation to engage in activities that benefit our brain, like spending time with others and exercising, she says.
Additionally, people with depression are more likely to smoke, drink excessive amounts of alcohol and take drugs, all of which raise their risk, notes Prof Quinn. So there’s not a single pathway linking depression to dementia.
Patients can reduce their dementia risk by seeking professional help for depression, such as therapy and medication, if needed, Thuret says.
“Engage in regular physical activity, practise mindfulness and meditation and maintain a healthy social life,” she adds.
We need pressure in our arteries to push blood around the body. However, if this pressure becomes too high, it can damage blood vessels, including those in the brain.
This raises the risk of vascular dementia and strokes, which damage brain cells, Thuret says. “It can also cause small vessel disease, contributing to cognitive decline,” she adds.
The only way to know if your blood pressure is high is to have a test.
“Monitor your blood pressure regularly and maintain a healthy diet low in salt and high in fruits and vegetables,” advises Thuret. “Exercise regularly, avoid smoking and limit alcohol intake. Take prescribed medications as directed.”
Both Type 1 and Type 2 diabetes patients can face a higher risk of dementia, though this does not mean that a person with diabetes will definitely develop the condition.
In Type 1 patients, it is because their blood sugar levels can drop too low (hypoglycemia), which can damage the hippocampus – the memory centre of the brain, says Quinn.
“Hypoglycemia is really bad for the brain, so people with Type 1 are walking this tightrope of trying to keep their blood sugars low to protect their blood vessels, heart, kidneys and eyes but not so low that it harms their brain,” he says.
In Type 2, hypoglycemia is “much less of an issue”, he says. Instead, these patients’ dementia risk is mainly driven by high blood sugar levels, which damage blood vessels that carry blood to the brain and the smaller blood vessels in the brain, Quinn explains.
“People who are able to get that happy medium of their blood sugar face a much lower risk than someone who has periods when their levels are really high or really low,” he adds.
Thuret advises that diabetes patients manage blood sugar levels through a healthy diet, exercise and medication. “Monitor blood sugar levels regularly and attend regular check-ups with your healthcare provider,” she adds.
We know obesity is bad for our health in many ways, raising the likelihood of developing Type 2 diabetes, heart attacks and strokes, as well as some cancers.
But being a dangerous weight is also a major risk factor for dementia.
“Obesity is linked to inflammation, insulin resistance and cardiovascular disease, all of which can affect brain health,” explains Prof Thuret. “Excess weight can also increase the risk of diabetes and high blood pressure, further contributing to dementia risk.”
People who are obese are also more likely to be physically inactive, which is another dementia risk factor. “If patients can combat that by just getting more active, they can tackle both their inactivity and weight in one go,” says Quinn.
Thuret also recommends that obese people eat a balanced diet, combine both aerobic exercise and strength training, and seek advice from a nutritionist if needed.
At least 150 minutes of moderate exercise (brisk walking, cycling, pushing a lawn mower) or 75 minutes of vigorous activity (running, swimming or football) a week is what we’re all told to do to benefit our overall health.
Failing to exercise enough increases our risk of dementia by up to 20%, research suggests. “Physical inactivity can lead to poor cardiovascular health, obesity and increased risk of diabetes and high blood pressure,” which are all dementia risk factors, explains Thuret.
She recommends 90 minutes a week of brisk walking, swimming, cycling or any other moderate-intensity aerobic exercise.
“For smoking, there’s no safe limit and even being in a household where there is a smoker is associated with an increased dementia risk,” says Quinn. Studies show that smoking increases the risk of dementia by 30 to 50%.
“Smoking causes oxidative stress, inflammation and damage to blood vessels, all of which can contribute to cognitive decline,” says Thuret. It also increases the risk of cardiovascular disease and stroke, which are linked to dementia, she notes.
To futureproof your brain health, give up smoking. Kicking the habit reduces the dementia risk to that of a non-smoker.
“Quit through cessation programmes, support groups, or medications,” Thuret recommends. “Avoid exposure to secondhand smoke and seek professional help if needed.”
“There used to be a school of thought that a low level of alcohol might be protective,” says Quinn. “More recent thinking has really challenged that.”
The Lancet report pointed to studies which have found that heavier drinking in midlife, classed as more than 21 units per week (nine standard glasses of wine or nine pints of beer), raises the risk of dementia by around a fifth compared to lighter drinking of less than 14 units per week – the upper limit recommended in the UK, which equates to six glasses of wine or six pints of beer.
However, Quinn notes research makes clear the more alcohol you drink, even at low levels, the bigger your risk of dementia. “Alcohol is toxic to the brain, it’s essentially a poison, albeit a lovely poison that I like to have on a Friday night,” he says.
Over time, excessive drinking causes areas of the brain required for memory and cognition to shrink and can lead to a vitamin B1 deficiency, which can also affect short-term memory, explains Prof Thuret. She recommends limiting intake to very moderate levels or forgoing it completely for brain health.
“I see lots of people who allow visual problems, whether from cataracts, macular degeneration or glaucoma, to get worse and worse because they think it’s just part of ageing and they don’t get treatment, which could completely change things,” says Quinn.
Research shows that failing to take action on sight loss can increase the risk of developing dementia by around 50%.
“Uncorrected vision loss can lead to reduced brain stimulation and social isolation, both of which increase the risk of cognitive decline,” explains Thuret. It can also make it harder to engage in physical and cognitive activities, which are also dementia risk factors, she adds.
“Have regular eye exams and wear corrective lenses as needed,” she recommends. “Address any vision problems promptly and use proper lighting to reduce eye strain.”
To function normally, the body needs some cholesterol – a substance made by the liver but also contained in fatty foods. There are two types: high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Too much LDL cholesterol causes a build-up of fatty plaques in blood vessels.
Studies show that for every 1mmol/L increases in LDL cholesterol, the risk of dementia jumps up by 8%, while having high LDL cholesterol (above 3mmol/L) raises the likelihood of the disease by 33%.
“The buildup of plaques in blood vessels leads to reduced blood flow and increased risk of stroke,” explains Thuret.
“Monitor cholesterol levels and maintain a healthy diet low in saturated fats and high in fibre,” she recommends. “Engage in regular physical activity, avoid smoking and take prescribed medications as directed.”
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