Dementia has long been thought of as an inevitable part of aging, but researchers are increasingly learning that’s not quite true.
About a third of dementia cases might actually be avoided by living a lifestyle that better protects your brain.
Dementia is how we describe symptoms that impact memory and lead to a decline in cognitive performance, often in ways that disrupt daily living. There are different brain disorders that cause dementia, but Alzheimer's is the most common, followed by cerebrovascular disease and Lewy bodies disease.
Around the world, some 47 million people are currently living with dementia — including more than 5 million Americans. The burden of Alzheimer’s alone on families and the health system is difficult to overstate: It’s the most expensive disease in America, costing up to $215 billion per year (more than double that of cancer or heart disease), and it can take a terrible toll on patient’s loved ones.
The number of people with dementia is also expected to triple worldwide by 2050 as populations age.
But there’s some good news: You might be able to modify some of your risk of developing dementia.
A major Lancet report, by 24 leading dementia researchers from around the world, zeroed in on nine of the best-known lifestyle factors that contribute to the illness and account for more than a third of dementia cases. The takeaway: Addressing these factors might be able to cut our dementia risk by up to 35 percent.
Another bit of good news is that the prevalence rate of dementia has declined in some countries, including in the US. And researchers think it may in part be due to increases in levels of education, which seems to protect people from getting dementia. For a disease many of us fear, the message is hopeful: Dementia is not necessarily an inevitability.
9 ways to cut your dementia risk
Dementia symptoms typically show up in old age, but the brain changes that cause it are thought to develop years earlier. These are things that might help stave off those changes:
1) Check your hearing and get a hearing aid if you need one
It’s not yet clear why, but there’s a strong correlation between even mild hearing loss and an increased risk in cognitive decline and dementia (and the dementia risk goes up with more severe hearing loss). Hearing may be important to dementia because of what study lead author, University College London professor Gill Livingston, called “the use it or lose it model.”
“We get a lot of intellectual stimulation through hearing,” she told Vox after the study was published in 2017. So when a person can’t hear as well their brain may begin to shrink. Researchers think hearing aids could help reduce that risk, but they need better evidence to know that for sure.
2) Keep learning
Less education is also associated with an increased risk of dementia because of something researchers call “cognitive reserve,” or a person’s resistance to assaults on the brain. “Low educational level is thought to result in vulnerability to cognitive decline because it results in less cognitive reserve,” they wrote, “which enables people to maintain function despite brain pathology.”
3) Stop smoking
Smoking is bad for the brain because it degrades cardiovascular health (and interferes the body’s ability to deliver oxygen to the brain). Tobacco also contains neurotoxins, which damage the brain.
4) Seek out treatment for depression
It’s still not entirely clear whether depression contributes to dementia, or whether dementia puts people at an increased risk of depression. But the researchers concluded that it’s “biologically plausible” depression boosts a person’s dementia risk because it “affects stress hormones, neuronal growth factors, and hippocampal [brain] volume.” Making sure people are treated for depression could mitigate a person’s dementia risk, and the researchers said antidepressants might also help, but called for better evidence to understand the effects of the medications.
Exercise is believed to protect the brain by reducing cortisol levels in the body, cutting vascular risk, and increasing the growth of nerve cells that are related to memory. So people who are inactive are at a greater risk of dementia because they don’t get the extra protection exercise confers.
6) Manage high blood pressure
Stress on the circulatory system increases the risk of neurodegeneration, which also contributes to dementia.
7) Be social
Like depression, it’s unclear whether social isolation is a symptom or cause of dementia. “However, evidence is growing that social isolation is a risk factor for dementia and it increases the risk of hypertension, coronary heart disease, and depression,” the researchers wrote.
The theory is that social isolation is similar to not being able to hear, Livingston explained. “You need a cognitively enriched environment to keep the brain in good health, and if don’t see people or can’t hear them, you get less of that stimulation.”
8) Maintain a healthy body weight
Researchers believe obesity causes brain damage because it’s linked with reduced blood flow to the brain and it increases oxidative stress, which is also bad for the brain.
9) Keep your blood sugar in check
People with diabetes are more likely to have dementia. One reason why: Having diabetes means you can no longer control your blood sugars. And having more sugar in your blood stream means more sugar in your organs, including the brain. So just as diabetes can damage other organs in the body, it also damages the brain.
By 2050, an estimated 140 million are expected to be living with dementia
This list of nine contributors is only the beginning. The scientific community is already learning about other potential contributors to dementia, such as exposure to pollution and lack of sleep.
“So we don’t think this [list of nine things] is everything but this is what we have evidence on now,” said Livingston in 2017.
There are other caveats to note about this research. Some of the factors — such as hearing loss, or social isolation — are again associated with dementia, but whether they cause dementia isn’t yet clear, and researchers are working to better understand dementia’s causes.
What’s more, not all cases of dementia are preventable; about 7 percent are linked with genetics and can’t be modified with lifestyle changes. And, the researchers wrote, “age, the greatest risk factor for dementia overall, is unmodifiable.”
Even so, Livingston added, people should think about finding ways to cut their dementia risk, and policymakers should think about creating environments that promote health. For example, some communities aren’t walkable, or lack strong tobacco control policies. Making exercise more accessible, and helping people quit their smoking habit, could reduce the dementia burden. Considering what a costly and devastating problem dementia is, we can’t wait for better evidence. And, it seems, even small steps toward living a healthier and more active lifestyle not only boost your overall health, but the health of your brain, too.