Diabetes, Prediabetes Could Prematurely Age Your Brain

Prediabetes and type 2 diabetes could accelerate how fast a person’s brain is aging, according to a new study.

It’s not the first time researchers have found a link between prediabetes, type 2 diabetes, and neurological health concerns.

However, this new study—published in Diabetes Care on August 28—used machine learning to quantify how the age of a person’s brain compared to their chronological age. They found that people with prediabetes and type 2 diabetes were more likely to have a brain age that was higher than their chronological age. Accelerated brain aging is associated with a higher risk of neurodegenerative disorders such as dementia, and mortality.

The findings could have significant implications, as some researchers predict 1.3 billion people could have diabetes by 2050.

“Diabetes is a well-established risk factor for dementia, but the role of diabetes and prediabetes in the early stages of brain aging is unclear,” Abigail Dove, a PhD student at the Karolinska Institutet Aging Research Center in Sweden, told Health. “These are important questions from a public health perspective because we need to understand how to protect the brain health of people with diabetes as they grow older.”

However, the study found a silver lining, too—making healthy lifestyle choices, such as not smoking, could mitigate this association.

Here’s what experts had to say about the new research, the connection between diabetes and brain health, and things you can do to keep your brain aging in a healthy way.

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For this study, Dove and her colleagues looked at brain magnetic resonance imaging (MRI) scans of more than 31,000 U.K. Biobank participants. These participants were between the ages of 40 and 70 and did not have dementia.

All participants received up to two MRI brain scans over the course of 11 years of follow-up. Then, the researchers used a machine learning model to help them estimate each person’s brain age in relation to their chronological age. Machine learning is a branch of artificial intelligence that uses algorithms to extract patterns from sets of data.

The researchers then looked at participants’ medical history and medication use to determine if they had prediabetes or type 2 diabetes.

Dove and her team found that, on average, prediabetes and diabetes were associated with brains that were 0.5 and 2.3 years older, respectively, than a person’s chronological age. Essentially, people with these conditions had brains that were aging faster than you’d expect for their age.

Though the connection between brain health and diabetes has been established, Dove said finding an association between faster brain aging and prediabetes in particular was interesting.

“This is the first study to examine prediabetes in relation to brain aging,” Dove explained. “We were surprised to find a relationship between the two, as prediabetes is indeed incredibly common and often goes undiagnosed and undetected. These findings encourage us to take prediabetes more seriously, not only because it is a high-risk state for diabetes, but because it may also negatively impact brain health.”

However, the researchers noted that more research (with a larger number of participants and a higher MRI frequency) is necessary to shed more light on this connection.

A handful of studies have previously looked at the relationship between diabetes and brain age.

One 2021 study found that being diagnosed with type 2 diabetes earlier in life was associated with a higher risk of dementia. Another study found that the longer a person has type 2 diabetes, the more likely they may be to experience changes in brain structure.

“Prediabetes and diabetes [have] a direct effect on brain aging and the risk of dementia,” Arman Fesharaki-Zadeh, MD, PhD, assistant professor of psychiatry and neurology at the Yale School of Medicine, told Health. “The onset of diabetes, especially in midlife, has been associated with increased risk of developing dementia.”

As for why this is the case, Fesharaki-Zadeh said it likely has something to do with the cardiovascular system.

Hyperglycemia—or high blood sugar levels—can promote oxidative stress, systemic inflammation, accumulation of potentially harmful compounds, and blood vessel issues that can lead to cardiovascular disease, Dove explained.

These can disrupt the blood-brain barrier, which exposes the brain to potentially toxic substances. Over time, this can lead to brain atrophy, issues with signaling within the brain, and other problems, she said.

Additionally, other research has shown that insulin resistance can reduce the supply of glucose to the brain, which can indirectly lead to a reduction in the brain’s white matter and production of Alzheimer’s disease-related proteins.

Because of their associations with neurodegenerative disorders, diabetes-related brain changes and accelerated brain aging in general are significant health concerns. But the good news is that there are things people with diabetes can do to lower their risk of accelerated brain aging.

The new study found that people with diabetes who were living an “optimal healthy lifestyle”—not smoking, no or light-to-moderate drinking, and high physical activity—had a smaller gap between their brain age and their chronological age.

In fact, the brains of people with diabetes were 0.78 years older on average if they adhered to this healthy lifestyle. But those who didn’t had brains that were, on average, 2.46 years older than their chronological age.

“Poor lifestyle choices, including a sedentary lifestyle, could lead to diminished physical activity and predisposition to poor metabolic control,” said Fesharaki-Zadeh. “Folks who often lead a sedentary lifestyle also tend to be more socially isolated—social isolation is also a risk factor for depression and diminished cognitive engagement, which are also potential risk factors for accelerated brain aging and dementia.”

In addition to living an active lifestyle, avoiding smoking, and lowering alcohol consumption, there are other things people with prediabetes or diabetes can do to reduce their risk of accelerated brain aging, Fesharaki-Zadeh said. These include: