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How to Lower Your Risk of Dementia While Living With Diabetes
Diabetes is linked to cognitive decline, but you can still protect your brain
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Key takeaways
- Type 1 and type 2 diabetes are linked to higher risk of vascular dementia and Alzheimer’s disease.
- Experts say managing A1C, blood pressure and cholesterol can support brain health while helping you avoid high and low blood sugar episodes.
- Heart-healthy habits like exercising, being social and eating healthfully can help lower dementia risk for people with diabetes.
After 54 years managing her type 1 diabetes, Riva Greenberg is focusing on how to protect her brain. Her mother and four aunts, none of whom had diabetes, all had progressive memory loss late in life. And she knows that diabetes is a risk factor for dementia. “I want to stop that before it happens,” she says.
Greenberg, 73, a writer and advocate who lives in New York, is taking steps to protect her brain: She follows a low-carb diet, takes twice-weekly exercise classes and goes on daily walks. She knows that decades of diabetes have put stress and wear on her body, including the blood vessels that feed her brain.
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High levels of sugar, or glucose, in the blood, which occur in type 1 and type 2 diabetes, damage the arteries’ inner linings. The arteries respond by adding layers of plaque, which makes it harder for oxygen-rich blood to get to the brain and other organs.
Dr. Medha Munshi, a geriatrician and endocrinologist at Harvard Medical School who directs the geriatric diabetes program at the Joslin Diabetes Center, confirms that prolonged high blood sugar (hyperglycemia) has been shown to increase the risk of dementia. Low blood sugar (hypoglycemia) is also dangerous for older adults, as it increases the risk of confusion and falls, which can lead to head injury, another risk for later dementia.
How does diabetes spike dementia risk?
Type 1 diabetes, more likely to occur in childhood, is caused by an immune response that damages the cells of the pancreas that make the hormone insulin. Type 2 diabetes, which is more often diagnosed in middle age or later, develops when cells no longer respond to insulin or when the body doesn’t produce enough of the hormone, which moves sugar from the blood into cells for energy. In both cases, without enough working insulin, sugar builds up in the bloodstream instead of reaching the cells that need it, leading to elevated blood glucose levels.
Both type 1 and type 2 diabetes raise the risk for vascular dementia and Alzheimer’s disease. “High blood sugar causes vascular injury over time, which is a route to vascular dementia,” Munshi says, adding that the Alzheimer’s connection is less understood.
High blood sugar was among the top modifiable dementia risk factors in a 2025 report by AARP, the Alzheimer’s Disease Data Initiative and the University of Washington’s Institute for Health Metrics and Evaluation. An estimated 40 million Americans are living with diabetes, and 115 million more have prediabetes.
Although type 2 diabetes is the more common type of diabetes among older adults, the number of older adults with type 1 diabetes is growing, according to research published in Nature Reviews Endocrinology. Because of advances in treatment and technology that allow for better glucose regulation, people with diabetes are living longer and contending with issues of aging, including dementia risk, in greater numbers than previous generations.
Joanne Milo, 72, who has lived with type 1 diabetes for 61 years, founded the advocacy group T1D to 100 to support people like her who are aging with the condition. “I’m in that demographic that has a higher incidence of dementia because we had less tight control. We just didn’t know what we didn't know,” says Milo, who lives in Southern California. “So damage has been done.”
The link between diabetes and dementia risk isn’t new, but it wasn’t known when Milo and Greenberg were young. A landmark 1999 study in the journal Neurology of more than 6,000 older adults in the Netherlands helped establish the connection. “We have known that for at least 20, 25 years, for sure,” Munshi says.
Milo’s approach to supporting her brain health is similar to Greenberg’s: Eat a healthy diet, exercise and find ways to socialize. “I spend a lot of time talking to people who are terrified” about aging with diabetes, she says. She tells them, “There are things you can do.”
Brainy advice for people with diabetes
“Better control of blood sugar in people with diabetes is related to better cognitive performance,” says Dr. Jose Luchsinger, a professor of medicine and epidemiology at Columbia University who studies memory disorders and aging. The goal in most cases, he says, is keeping the three most important measures for diabetes health — A1C, blood pressure and cholesterol — within standard recommended targets rather than pushing for the lowest numbers possible.
For older adults with diabetes, “control” doesn’t mean hitting the lowest possible A1C. Instead, it means more time keeping glucose levels in a safe range, Munshi says.
For Milo, putting this definition of glucose control into practice meant breaking out of the common mindset of “lower numbers mean better control, and better control means lower risk of complications.” Advances in diabetes technology — such as continuous glucose monitors, insulin pumps and automated insulin delivery systems — make that pursuit possible with settings that can tighten control and reduce blood sugar variability but often at the cost of more frequent hypoglycemia.
Seeing low numbers can feel empowering and safe, Milo acknowledges, but her endocrinologist said it could be harmful at her age. “ ‘What’s your point here?’ ” she remembers him saying. “ ‘Can you shave a point off your A1C? Is it worth it? Is it going to help you? Could you just lighten up?’ ”
It seemed counterintuitive, but she raised her target range and eased her settings. Her A1C blood test crept up to the mid-5s and is now closer to 5.9. For most people with diabetes, the A1C goal is 7 or lower, according to the American Diabetes Association. “My first reaction was ‘Uh-oh, no,’ ” Milo says. “And then I thought, I did this on purpose.”
Milo hasn’t noticed any change in how she feels, other than the relief of not chasing a perfect number.
For people with type 2 diabetes, researchers are studying whether certain diabetes drugs can offer brain protection. Luchsinger says it’s a worthwhile area of research, but the science isn’t yet there.
He coauthored a study of more than 3,700 people with type 2 diabetes, published in 2025 in JAMA Internal Medicine. The study compared four types of glucose-lowering medications when each was taken in combination with metformin, one of the most common first-line medications for type 2 diabetes. The researchers found no improvement in cognitive performance after four years.
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“Based on the best evidence that I know about, there’s really no benefit of those medications” when it comes to brain health, he says, though he noted the study duration was short and its population was relatively young, in their 50s and 60s. He is planning further research.
The possible cognitive benefits of metformin remain intriguing but unproven, Luchsinger says. So far, speculation about the brain effects of GLP-1s, commonly used to treat diabetes and made popular for weight loss in recent years, and SGLT2 inhibitors, which reduce glucose levels but also have heart and kidney benefits, has outpaced the evidence, he adds. Researchers continue to study the impacts of these drugs on brain health.
Munshi cautions that despite real cardiovascular and kidney benefits of these drugs, they can carry risks for older adults: “Excessive weight loss and having increasing frailty and increasing risk of falls also need to be considered.”
Dementia can make managing diabetes harder
“I see it as a two-way relationship between diabetes and cognitive decline,” says Dr. Richard Dupee, chief of geriatric medicine at Tufts Medical Center. Not only is the risk of dementia greater with diabetes, but having dementia can also make taking care of diabetes much harder. “If you have cognitive decline, you lose executive function planning,” he says, “and therefore, it’s very difficult to manage your diabetes.”
Symptoms to watch for, especially in the early stages of vascular dementia, are often subtler than classic memory loss, Munshi says. They include new medication errors, missed meals and more frequent high or low blood sugar episodes. Anyone with concerns should talk to their medical team.
“It’s always a good idea to get tested,” Luchsinger says, adding that most health care providers can either administer a cognitive screening or make a referral for one. Most people who get tested are reassured, he says, and for those who aren’t, earlier detection can mean earlier access to treatment.
How to lower your dementia risk
Luchsinger says there’s wide agreement among neurologists that anything that helps protect the heart and reduces risk of a stroke also protects the brain and lessens the risk of developing dementia.
“Broadly speaking, in people with diabetes, control of your glucose and control of your cardiovascular risk — particularly controlling your blood pressure and your cholesterol — is good,” he says.
A persistent belief that statins, widely prescribed for lowering cholesterol, may increase dementia risk — rooted in earlier studies showing correlation, not causation — has been refuted by recent studies finding that their use may actually cut dementia risk.
An observational study published in 2026 in The Lancet Regional Health Europe underscores this, showing that the use of statins to bring down cholesterol within a year of diagnosis of type 2 diabetes reduced participants’ dementia risk by 15 percent after a decade.
Dupee emphasizes certain modifiable risk factors for dementia that people should pay attention to. “Control the blood pressure, control the lipids, don’t smoke, exercise, eat well, remain socially engaged,” he says. That includes aerobic activity plus resistance training, sleep and hearing correction. He also points to the risk of hypoglycemia, which can lead to falls and traumatic brain injury, another risk factor for dementia.
Munshi puts one action at the top: “Exercise, I think, is the only fountain of youth.”
Greenberg and Milo have built their routines around this advice. For Greenberg, movement is nonnegotiable. She takes frequent exercise classes and near-daily walks, and does weekly online qigong, a gentle mind-body practice involving slow movement and breathing exercises similar to tai chi.
“Stay socially connected,” Milo says. “When you don’t, you start to shut down.”
Mindful of her family history with cognitive decline and her decades of living with type 1, Greenberg is focused on what she can control. Lately, she has sought out as many mini interactions as she can throughout her day. “When we are a little more social, it makes us happier,” she says. It takes some courage, but with practice she has gotten better at striking up conversations with strangers. “You both end up feeling better,” she says. “I think this is enormous for brain health.”
The key takeaways were created with the assistance of generative AI. An AARP editor reviewed and refined the content for accuracy and clarity.
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