Thomas’s mother, Maria*, has lived with type 2 diabetes for more than a decade. Her dementia diagnosis still came as a shock. “I always knew my mother’s diabetes could affect her heart or kidneys,” he recalls. “What I didn’t expect was how it might affect her memory. That was something I thought only happened to much older people.”
Ageing has long been linked with weight gain, cardiovascular disease and a higher likelihood of developing diabetes. Less widely recognised is how these conditions intersect with a cluster of risk factors known as metabolic syndrome.
Metabolic syndrome is not the same as obesity. It refers to conditions that often occur together: excess abdominal fat, raised blood pressure, high blood sugar or insulin resistance, and abnormal cholesterol levels. Importantly, people with overweight or obesity are not the only ones at risk. Some people with a normal weight can still develop metabolic syndrome, often described as “metabolically unhealthy normal weight” or the “thin-fat phenotype“.
Rather than a single condition, metabolic syndrome reflects a broader imbalance in the body’s metabolism and serves as a warning sign that multiple systems are under strain. Together, these conditions increase the risk of long-term health problems.
Importantly, people with overweight or obesity are not the only ones at risk. Some people with a normal weight can still develop metabolic syndrome
Diabetes, metabolic syndrome and dementia create a “triple burden” that affects not only the individual but also their families, caregivers and the healthcare systems that support them. Yet the deeper connections between these conditions are less widely recognised.
The factors driving metabolic syndrome also stress the brain. Chronic inflammation and damage to blood vessels reduce the flow of blood and oxygen to the brain. At the same time, insulin resistance makes it harder for the brain to metabolise glucose, its main source of energy. Over time, these processes can accelerate the build-up of amyloid-β and tau proteins, the hallmark features of Alzheimer’s disease, the most common form of dementia in people with diabetes. Vascular dementia is also common in people with diabetes because of the impact of high blood pressure, high cholesterol and damage to blood vessels in the brain. In some cases, both conditions overlap, known as mixed dementia.
These vascular and metabolic complications shed light on why people living with metabolic syndrome and type 2 diabetes are at higher risk of cognitive decline and dementia. With growing awareness of this connection, healthcare professionals are treating metabolic syndrome not only as a cardiovascular concern, but also as a condition with profound implications for brain health.
Today, more than half a billion people live with diabetes, mostly type 2. This figure is projected to rise to 853 million by 2050, with over three in four people affected living in low- and middle-income countries. Dementia, led by Alzheimer’s disease, adds yet another burden. In 2021, 57 million people worldwide lived with dementia, and this number is expected to nearly triple by 2050.
Dementia, led by Alzheimer’s disease, adds yet another burden. In 2021, 57 million people worldwide lived with dementia, and this number is expected to nearly triple by 2050
Metabolic syndrome describes the clustering of visceral fat or abdominal obesity, high blood pressure, unhealthy cholesterol levels and high blood glucose. Having three or more of these factors increases the chance of developing type 2 diabetes and raises the risk of cognitive decline. Globally, the condition affects an estimated one in four adults.
Maria was diagnosed with type 2 diabetes in her early fifties. She already had high blood pressure and elevated cholesterol, placing her firmly in the category of metabolic syndrome. “Looking back,” Thomas says, “the doctors were always focused on her sugar levels. Mum had high blood pressure, high cholesterol and diabetes and used to complain about headaches and tiredness. Nobody really talked to us about how all these things together could affect her brain.”
Insulin resistance, the cornerstone of type 2 diabetes, is increasingly recognised as a link to dementia. For Maria, the pathway from diabetes to memory loss became apparent only years after her diagnosis.
Research confirms that people living with metabolic syndrome or diabetes face a higher risk of dementia, particularly if diabetes is diagnosed earlier in life. A meta-analysis of 14 long-term studies reported that people with metabolic syndrome face a 12% higher risk of developing dementia of any cause. The link with Alzheimer’s disease is less clear, but evidence is growing. Data from the UK Biobank, one of the world’s most extensive health studies, found that metabolic changes such as raised blood pressure, abnormal cholesterol or insulin resistance increase dementia risk in people younger than 65—even when obesity is not present.
For Thomas, these findings resonate personally. “Mum was only in her fifties when she was diagnosed with diabetes. Now, ten years on, she’s showing signs of mild cognitive impairment. I can’t help but wonder if things would have been different if her risk had been spotted earlier.”
Metabolic changes such as raised blood pressure, abnormal cholesterol or insulin resistance increase dementia risk in people younger than 65—even when obesity is not present.
Another dimension is the economic burden. Dementia accounts for over US$1.3 trillion annually in healthcare and caregiving costs. When diabetes and dementia occur together, expenses multiply, not just for health systems but also for families. Maria’s family, like many others, now balances medical expenses with the unpaid time Thomas spends organising her appointments, checking her medications, and ensuring she eats properly. “It’s not just about money,” he says. “It’s the hours, the energy, and the constant worry.”
As with many preventable conditions, early intervention can reduce risks. In primary care, routine checks of waist circumference, blood pressure, glucose and cholesterol can pinpoint problems long before symptoms appear. For people living with diabetes, this type of monitoring benefits not only heart and kidney health but also brain health.
Maria’s memory lapses were first noticed during a routine diabetes checkup. Her healthcare team carried out a brief cognitive test, which indicated mild cognitive impairment. For Thomas, the diagnosis was both frightening and clarifying. “It was hard to hear, but at least we had an explanation. And it gave us a chance to do something before it got worse.”
Yet access to early screening is far from equal. In many low- and middle-income countries, primary care systems are under-resourced, blood tests remain inaccessible to large parts of the population, and cognitive assessments are rare. In some cultures, memory loss is viewed as a normal part of ageing, which can delay diagnosis further. And even when conditions are identified, access to new therapies or structured prevention programmes remains limited. This inequity means that people like Maria in high-income settings may benefit from timely support, while millions in lower-income regions face the same risks with fewer opportunities for intervention.
Dementia accounts for over US$1.3 trillion annually in healthcare and caregiving costs. When diabetes and dementia occur together, expenses multiply
Emerging research offers hope for new approaches to protect brain health in people with metabolic disorders. Glucagon-like peptide-1 receptor agonists, widely used for diabetes and weight management, are now being studied for their cognitive benefits. A phase 2 trial of liraglutide showed slower brain shrinkage and an 18% slower rate of cognitive decline in people with early Alzheimer’s disease, and larger semaglutide trials are underway. Intranasal insulin, designed to deliver the hormone directly to the brain, has shown mixed results but continues to be investigated.
Lifestyle interventions remain a cornerstone. Adopting healthy nutrition like a Mediterranean-style diet and eliminating ultra- and highly-processed foods has been shown to influence dementia-related metabolic pathways, particularly in people carrying the APOE4 gene, a gene variant strongly linked to a higher risk of developing Alzheimer’s disease and other types of dementia. Regular physical activity improves blood vessel health and insulin sensitivity, both of which contribute to cognitive resilience.
Natural compounds are also under study. A 2025 meta-analysis found that mulberry extract improved glucose and lipid metabolism, reduced inflammation and lowered HbA1c in people with metabolic disorders. These results suggest a potential strategy for preventing vascular dementia. Though cognitive outcomes were not directly measured, the improvements in metabolic health are promising.
For Maria, the therapies that make headlines are not yet part of her reality. Her daily focus remains on walking with her neighbours, following dietary advice and taking her prescribed medicines. But Thomas finds hope in the possibility that new treatments may one day ease the path for other families. “Even if they can’t help Mum now,” he says, “maybe they’ll help someone else’s mother in the future.”
Glucagon-like peptide-1 receptor agonists, widely used for diabetes and weight management, are now being studied for their cognitive benefits
While Alzheimer’s disease and dementia represent the most severe outcomes, brain health exists on a continuum across the lifespan. Framing brain health more broadly opens the conversation to younger people living with metabolic syndrome or diabetes. Sleep, physical activity, balanced nutrition and social connections all play a role in cognitive resilience. In this way, brain health becomes a lifelong goal, not simply a concern for later years.
Thomas saw this first-hand. “When Mum first started forgetting things, I thought it was just ageing. But now I see that her diabetes and weight were putting her brain under strain for years. I think about my own health differently now. I try to eat better and exercise, not just to avoid diabetes but to keep my brain sharp too.”
Healthcare professionals can bridge the gap between diabetes care and brain health. Talking openly about the links between metabolic health and dementia helps people understand their risks and motivates them to take preventive action. Primary care teams need training to recognise overlapping risk factors and provide culturally sensitive support.
Structured prevention programmes that combine education, nutrition and physical activity are especially valuable. Gender-sensitive approaches are also needed, given the additional risks faced by women. Globally, health systems must align dementia and diabetes action plans, particularly in low-resource settings where the burden is heaviest.
For Maria, policy changes cannot come soon enough. “I wish someone had told us years ago that diabetes could affect her memory,” Thomas reflects. “Maybe then we could have made different choices earlier.”
With global life expectancy increasing, the overlap of metabolic syndrome, dementia, and diabetes poses a growing health challenge. The biological links are strong, the economic and social costs are high, and the personal consequences are profound. For Maria and her son Thomas, the journey illustrates both the risks and the opportunities. Early detection of cognitive changes gave them time to act, to adjust lifestyle habits and to seek support. Their story demonstrates that protecting brain health should be an integral part of diabetes care everywhere.
As Thomas puts it, “Mum’s memory isn’t what it used to be, but she’s still here, still herself. If sharing our story helps other families take action sooner, then it’s worth it.”
* Thomas and Maria’s story is a composite, drawn from the lived experiences of several families who shared how diabetes and dementia shaped their lives.
What do type 2 diabetes and dementia have in common? In this podcast, host Phyllisa Deroze speaks with Professor Kaarin Anstey, a leading expert in ageing and brain health, to unpack the growing evidence linking the two conditions. Drawing on insights from the 11th Edition of the IDF Diabetes Atlas, they explore how the age of diabetes onset, vascular risks, and long-term management can influence cognitive decline. With dementia cases rising fastest in low- and middle-income countries, this conversation shines a light on why early detection, lifestyle interventions, and integrated care must be part of the global health agenda.
