Dementia, or loss of memory and cognition, is more common in people with diabetes because their biological age is higher than their chronological age.
Published Dec 02, 2025 | 7:00 AM ⚊ Updated Dec 02, 2025 | 7:00 AM
Dr V. Mohan, Endocrinologist and Chairman of Dr Mohan’s Diabetes and Research Centre, Chennai.
Synopsis: Dr V Mohan, an endocrinologist and Chairman of Dr Mohan’s Diabetes and Research Centre in Chennai, explained how diabetes may increase the risk of dementia, what early warning signs to watch for, and how new research could help prevent it.
Dementia slowly affects memory, thinking, and daily functioning as the brain ages. Most people know that diabetes can harm the heart, kidneys, or eyes — but only a few realise it can affect the brain too.
In an interview with South First, Dr V. Mohan, an endocrinologist and Chairman of Dr Mohan’s Diabetes and Research Centre in Chennai, explained how diabetes may increase the risk of dementia, what early warning signs to watch for, and how new research could help prevent it.
His upcoming study, a collaboration between the Madras Diabetes Research Foundation, IISc’s Centre for Brain Research, and the UK Dementia Research Institute, aims to detect early signs of brain changes in people with diabetes and test ways to prevent cognitive decline.
Q. Many people know diabetes affects the heart, kidneys, or eyes, but not the brain. In simple terms, why does having diabetes increase a person’s risk of dementia?
A: Diabetes can affect the brain in many ways. Just as it affects the heart, it can affect blood circulation to the brain.
Stroke can happen — either hemorrhagic or thrombotic — and diabetes is one of the causes. But beyond strokes, diabetes itself accelerates ageing.
Dementia, or loss of memory and cognition, is more common in people with diabetes because their biological age is higher than their chronological age.
I like to explain it this way: Suppose you’re 60 years old. If you don’t have diabetes, your biological age — how old your arteries and nerves are — is close to your actual age. But if you have diabetes, your arteries and nerves may be like those of a 70- or 75-year-old. Diabetes generally adds about 10 years to your age.
Combine that with high cholesterol, high glucose, inflammation, oxidative stress, and reduced blood flow, and you get why dementia is more prevalent in diabetics.
Q. Are certain types of dementia, like vascular dementia or Alzheimer’s disease, more strongly linked to diabetes? If so, why?”
A: When we talk about dementia, the two main types are Alzheimer’s disease and vascular dementia. In Alzheimer’s, the brain degenerates, and amyloid and other deposits form tangles, like hair getting knotted.
Nerves get tangled, information can’t flow properly, and memory, judgment, and cognition decline. Alzheimer’s is definitely more common in people with diabetes — about double the risk compared to the general population.
Vascular dementia comes from damaged blood vessels in the brain. Diabetes harms the vasculature, just like it damages the heart, eyes, and kidneys.
So it is also more common in people with diabetes. Sometimes, patients even have a mix of Alzheimer’s and vascular dementia. Overall, all forms of dementia are more frequent in diabetics.
Q. What kind of changes, either in the body or brain, might show up years before memory problems begin in people who are suffering from diabetes?
A: The first signs are subtle and can look like normal ageing. People start forgetting names, misplacing things, or entering a room and wondering why they came there. Mild cognitive impairments can show up in tasks like drawing a clock incorrectly.
However, today, we can detect early changes with MRI scans and blood tests. Biochemical markers for dementia can become abnormal even five to 10 years before symptoms appear.
Once we identify someone at risk, we can intervene with diet, exercise, mental games, and even some emerging medications that target amyloid deposits in the brain. In some cases, these treatments can dissolve the tangles and help improve memory.
Q. Do we know whether good diabetes control, like keeping sugar levels stable, can actually slow down or reduce damage to the brain over time? What does current evidence suggest?
A: We don’t have large studies proving that controlling diabetes stops dementia, but my clinical experience shows it helps. Some of my patients in their 90s or even 100s are still mentally sharp, while others develop severe dementia by their 70s or 80s.
The difference often comes down to what I call the ABCD mantra: A for A1C, keeping your three-month sugar control steady; B for blood pressure; C for cholesterol; and D for discipline, maintaining a healthy diet, exercising, sleeping well, and following regular checkups.
Following the ABCD approach seems to slow dementia and prevent other complications in people with diabetes.”
Q. Your collaboration with IISc’s Centre for Brain Research and the UK Dementia Research Institute marks a shift from traditional diabetes research to neurodegeneration. What motivated this cross-disciplinary leap, and what unique Indian perspectives or datasets does this project bring to global dementia research?”
A: Indians develop diabetes and related complications at a younger age, and there’s evidence that dementia may appear earlier as well. People with diabetes experience accelerated ageing, making them a good population to study.
That’s why we started this collaboration with the Centre for Brain Research at IISc and the UK Dementia Research Institute.
We’re combining biochemical testing in India with clinical dementia expertise from the UK. Blood samples from diabetic patients will be analysed for early dementia markers.
We’ll test interventions such as better diabetes control and healthier food. The UK team provides guidance on screening and treatment.
Our goal is to preserve brain function and prevent dementia before it becomes severe, especially as life expectancy in India rises.
At our centre in Chennai, anyone above 60 can get free dementia and ageing screenings. We want people to grow old gracefully, without rapid cognitive decline.
We are trying to set up healthy ageing clinics, where we can screen older adults for memory, physical strength, and overall wellness, even if they don’t complain of memory loss.
The aim is to detect dementia early, provide interventions, and allow people to grow old gracefully without rapid cognitive decline. Diabetic clinics now have a unique opportunity to play a role in early detection and prevention.
(Edited by Muhammed Fazil.)
