Any kind of diabetes diagnosis brings worries about long-term health of the eyes. The kidneys. The feet. The heart.
But experts now say that potential damage to the brain needs to be a focus in diabetes care, too. It’s a scary thought, and not something often top of mind (no pun intended).
“When we think of the kidney, we picture dialysis. When we think of the eyes, we picture blindness,”Marjorie Madikoto, diabetes care and education specialist (DCES) and founder of the Diabetes Management Institute in Maryland, told DiabetesMine.
“But the brain is hidden away, tucked inside us. So, it’s the last thing around diabetes we think about. It’s just not a visible organ,” she said.
That often leads patients, and healthcare providers alike, to pay little attention to the impact of diabetes on the brain.
That is changing. New technology is allowing scientists to better track what’s going on in the brain in people with diabetes (PWDs), and emerging studies are finding evidence of how extreme high and low blood sugars may impact brain function.
What are the risks to know about? This field is learning as we go. But links to Alzheimer’s and other forms of dementia seem clear.
Here’s what we understand so far about how diabetes can affect your brain, and what you can do to ward off damage.
A new and comprehensive study published in January of 2021 by Diabetes Care pointed to some surprising outcomes.
This research included children ages 6-12 who had been diagnosed with type 1 diabetes (T1D) for just a few years. The findings? Hyperglycemia (extreme high blood sugar) may begin the process of brain deterioration nearly immediately in a child with diabetes.
The study followed 144 children with diabetes and 72 without diabetes to assess brain function using total brain, gray, and white matter volumes and full-scale and verbal intelligence quotients (IQs) as their measure.
Their main objective was to assess brain and cognitive differences between children with T1D and control subjects. Researchers also gauged whether the condition persists, worsens, or improves as children grow into puberty, and what differences are associated with hyperglycemia.
Findings indicate that total brain, gray, and white matter volumes and full-scale and verbal intelligence quotients (IQs) were lower in the diabetes group at 6, 8, 10, and 12 years. The differences at baseline persisted or increased over time.
Further, the study showed, those impacts negatively correlated with a life-long elevated A1C and higher daily glucose values in diabetes.
That tie to hyperglycemia came as a surprise to the study team, study author Dr. Nelly Mauras, chief of the division of pediatric endocrinology at the University of Florida, told DiabetesMine.
“We had previous data, dating back 8 years, so we already knew there were differences (in the brains of children with diabetes),” she said. “But we were expecting to see a strong correlation to hypoglycemia (extreme low blood sugar). What we found was the strongest association is with hyperglycemia.”
Another important takeaway from this research is that impacts to the brain begin to set in quickly after diagnosis, according to study co-author Dr. Allan Reiss, professor of psychiatry, behavioral sciences and radiology at Stanford University.
“The dogma of ’10 years before complications set in’ is falling apart,” he said.
But the study leaders caution parents: Don’t panic.
“This is not meant to scare anyone,” Mauras said. Rather, it’s important to have tangible evidence of this previously unknown connection, she said, because “you use your brain every day.”
Reiss said that the early impact could be seen on the frontal lobe, “the seat of reason or the ‘executive processing’ part of the brain, that part that allows us to plan.”
He said other parts of the brain saw impact too. This, he believes, should help guide clinicians and parents going forward.
Still, he said, panic is not the answer.
“The changes are very real, but don’t be paranoid. Be aspirational… this is one more reason why blood sugars need to be controlled,” he said.
The team will dig into a follow-up study looking at what may may happen next, and whether these brain changes might be reversible.
Mauras wonders, too, if the findings tie into another struggle many adolescents with diabetes have: burnout and daily care struggles.
She notes that only 17 percent of children reach the ADA target A1C range of 7.5 percent or lower.
“You wonder if the reason kids have A1Cs in the 9, 10, and 11 range is that they are having trouble (with their daily care tasks),” she said. “It would be nice to do a study on that.”
Technology is a game-changer in this regard, she added.
“The good news is that this information is coming at a time when you can see blood sugars in near real-time.”
It’s also a time when the field is learning more about how Time in Range is as important (and some say more important) than A1C.
Reiss said with good tools and proactive work, “there is no reason to think you cannot significantly (improve) things. The brain is very good at recovery,” he said.
For him, that calls for the need to improve access to care and tools for all PWDs. “The issue of equity in technology is huge,” he said.
What about the long-touted links between diabetes and other diseases of the brain such as Alzheimer’s and other forms of dementia? Those links are very real, as evidenced by research.
And more recently, studies have found a near direct link to diabetes and Alzheimer’s disease, as shown in this
“We’re learning there is a very strong link in diabetes that is not well-controlled and the stress it puts on the brain,” Suzanne Craft, PhD, professor of gerontology and director of the Alzheimer’s Disease Research Center at Wake Forest University, told DiabetesMine. She has been studying the link between diabetes and brain health for years.
Damage to the brain is caused the same way diabetes impacts all other organs, she said: from an overabundance of glucose, which corrodes certain tissues.
She also points out that for PWDs with widely varied blood glucose levels, the impact on other organs can also negatively impact the brain.
“The heart, for example,” she said. “Blood vessels impact the brain too, and when the heart has trouble, it impacts the brain.”
For most people, though, there’s a way to reduce the risk.
“By controlling your diabetes and doing well, you really can cut down the chances for negative brain impact,” she said.
With type 2 diabetes, which is closely tied to Alzheimer’s, she said, “The better you can control it with a healthy lifestyle, lower weight, physical activity five times a week and eating healthy food, the more chance you have of avoiding it.”
Craft points out that the larger aging population with diabetes isn’t just because diabetes is more prominent. It’s because people with diabetes are living much longer than they once did.
“Thankfully, we are better at cutting down and reversing risks,” she said. “We’re saving people.”
That comes at a cost, though: With the diabetes population living longer, the aging brain and how diabetes impacts it is relatively new to science, research and treatments.
In January, a study led by Dr. George King, chief scientific officer at Joslin Diabetes Center, found that routine eye imaging can identify changes that may be associated with cognitive disorders in older people with T1D.
Those findings may lead to earlier intervention and hopefully better treatments to offset or reverse the damage diabetes can do to the brain over the years, King told DiabetesMine,
Why now? King points out the same thing Craft did.
“Cognitive decline does not happen until a person with T1D is around 60 to 80 years old,” he said.
“To be blunt: they weren’t living that long until recently,” he said.
With the Medalist study having access to thousands of people who have had T1D for 50 years or longer, these researcher now have the pool needed for study.
King said he and his team already understood there could be a link between retinal changes and brain issues.
“During fetal development, the eye is a development or ‘out pouch’ of the brain,” he explained.
“It’s also well known that type 2 cognitive decline can be due to vascular/blood vessel disease,” he added. “So, I thought: With all the new imaging techniques we have (such as the ability to look at multiple layers of the eye and the small blood vessels in those layers), could we see how they correlate to the brain?”
The answer: Yes, they can.
“This can be done with a simple five-minute procedure, which means that we can look at what’s going on in the brain via the eye and take earlier action when needed,” he said.
More research needs to be done (including a wider reaching pool of younger participants with both types of diabetes), but King plans on pushing for that.
His team’s goal? To do for brain issues and diabetes what they’ve done for eyes.
“We’ve brought blindness down to 1 percent of people with T1D,” he said. “Why not the brain?”
King hopes to find new treatments and pushes to prove that via the eye, early brain change detection can lead to better outcomes.
“I think this is very helpful news,” he said. “When (the study) first came out, people said ‘oh no, another problem,’ but I look at it this way: It’s our chance to take action. We’re looking ahead, and want to find the early interventions that change this.”
These clinicians agree that the best defense for anyone with diabetes is education.
“Care for a person with diabetes can be almost conveyor belt-like,” said the Diabetes Management Institute’s Madikoto, meaning daily tasks just keep coming at them, often leaving little time to think about the big picture.
“But the main reason patients do well is this: education,” she said.
In her practice, she likes to show PWDs a chart of the body and ask them to point to the places diabetes may impact them negatively.
They typically point to the eyes, the feet, the kidney area, but seldom, if ever, the brain. But they should.
“Like the eyes, the small vessels are where damage can happen first,” she said.
Then, when patients understand that, they should not assume a low A1C is the solution, she said. Like most things in diabetes life, the answer seems to be balance.
“An A1C of 5.0 or 6.0 does not mean you’re necessarily ‘in control,’” she said.
“That often can come with — when looked at closely — too many lows,” she said. “The brain depends on glucose, so it has to have food. Low blood sugars starve the brain.”
Instead, she would like to see adults with diabetes — and parents caring for T1D children — to start focusing on increasing Time in Range. This also helps them find balance.
Focus should also be placed on paying attention to the signs of lows. Parents can help their children recognize symptoms so they can take action early. Adults often need to re-commit themselves to paying attention to oncoming lows as well.
For her part, Craft with Wake Forest’s Alzheimer’s Center says her message is that it’s never too late. For that reason, she wishes more people with diabetes would focus on brain health.
“People often don’t become motivated (to take action) until something appears,” she said.
Even if you’ve not been motivated yet, she said, today is the day.
“It’s never too late to turn things around,” she said.