Strides have been made in the world of dementia research compared with even just a few years ago. There’s now a blood test that can diagnose Alzheimer’s accurately 90% of the time, and more is understood about the factors (many of which are lifestyle habits) that can put you at higher risk for the condition.
In a 2024 dementia report published in The Lancet journal by researchers who are part of The Lancet Commission, two new modifiable risk factors have been identified: high cholesterol after 40 and untreated vision loss.
In 2020, these same researchers determined 12 modifiable risk factors that are known to put folks at higher risk of developing dementia. These are:
Physical inactivity Smoking Alcohol consumption Air pollution Head injury Infrequent social contact Less education Obesity Hypertension Diabetes Depression Hearing impairment
According to the report, these 12 factors, along with the two new ones, account for 49% of dementia cases across the world. Researchers determined these two new risk factors by looking at recent meta-analyses and studies on the topics; they looked at 14 papers on vision loss and 27 on high cholesterol.
“It makes a lot of mechanistic sense,” said Dr. Arman Fesharaki-Zadeh, a behavioral neurologist and neuropsychiatrist at Yale Medicine in Connecticut. “A lot of these factors are very much interrelated.” (Fesharaki-Zadeh is not affiliated with the report.)
“There are many sources of vision loss, of course, but it tends to be a lot more common in folks who have metabolic risk factors such as high blood pressure, such as poorly controlled diabetes, such as high cholesterol, which is the other risk factor [identified in the report],” he said.
Vision loss
Moreover, vision is our primary sensory organ — it’s how we process the world around us — and when you can’t see clearly, you’re less likely to spend time doing brain-boosting activities like puzzles, reading or even spending time with other people, said Fesharaki-Zadeh. And these activities are known to help prevent dementia.
Bad Cholesterol
When it comes to high LDL cholesterol (the so-called bad cholesterol), it can lead to the hardening of the blood vessels in the heart and brain, Fesharaki-Zadeh said, adding that high blood pressure and uncontrolled diabetes also affect the blood vessels.
This can make it more difficult for oxygen to get to the brain, which over time can lead to neuron damage — “and dementia is essentially an end product of the neuron’s dying out, so it’s a neurodegenerative process,” Fesharaki-Zadeh explained.
“I can’t tell you how often I see in our patient populations, especially folks above the age of 60, there are certain parts of the brain that are more vulnerable to damage … and these are the areas that are especially vulnerable to hardening of blood vessels. Someone who has … high cholesterol, the correlation between that and hardening of blood vessels is quite high, and we see it in our clinical setting very frequently as well.”
“The saying that I like to use with patients quite often is what affects your heart will affect your brain, and we see that time and time again,” the doctor said.
If you suffer from vision loss, it’s important to manage it for the sake of your future health.
How you can lower your risk
“I cannot highlight the importance of a collaborative model between primary care physicians and specialties,” said Fesharaki-Zadeh. Having a primary care doctor who understands your health and is willing to share pertinent information with specialists, like cardiologists and neurologists, will help you stay on top of any issues putting your well-being at stake.
Your primary care doctor should also be proactively working to help you control the risk factors — like high cholesterol and high blood pressure — whether that’s through medication, diet or exercise.
Fesharaki-Zadeh said you and your doctor should focus on these lifestyle changes as early as possible, at least in midlife, not when you’re at the point when dementia starts to show up.
“The front line of medical care are primary care physicians. These are the folks that, by having early discussions … can go a long distance to prevent the onset of dementia,” he explained.
There are also tests that can detect early signs of neurodegeneration and genetic markers of the disease. A primary care doctor can help you learn about these options.
“Up to 40% of dementias are potentially preventable,” he added, but it’s worth noting that dementia can also be genetic, which makes prevention trickier. But someone who is diagnosed with dementia or mild cognitive impairment can benefit from managing these risk factors, too.
“The research is also showing that if you have two groups of individuals, someone who has comorbid metabolic diseases such as hypertension, high cholesterol, diabetes, versus somebody who doesn’t, and both of these individuals have dementia, the rates of progression of dementia in somebody who doesn’t have metabolic risk factors tend to be slower,” explained Fesharaki-Zadeh.
It’s never too late
It’s never too late to make changes and corrections, he noted, whether you’re a young, seemingly healthy person, in your 80s or 90s, or someone who has already been diagnosed with dementia.
Our brains are highly malleable, Fesharaki-Zadeh said. So if you decide to make healthy lifestyle changes at any point, your brain will respond and be healthier for it.