Nearly half of all dementia cases may be linked to risk factors people can influence, according to new research from Lund University in Sweden. The findings suggest that lifestyle and metabolic health are closely connected to physical changes in the brain long before symptoms appear, reinforcing growing evidence that protecting cardiovascular health may also help preserve cognitive function.
The study followed nearly 500 cognitively healthy adults and examined how common modifiable risk factors—including smoking, high blood pressure, diabetes and abnormal cholesterol levels—were associated with changes linked to both vascular dementia and Alzheimer’s disease.
How the Swedish study was conducted
The researchers tracked 481 adults with an average age of 65 who showed no signs of cognitive impairment at the beginning of the study. Over a four-year period, participants underwent repeated brain imaging and biomarker testing to monitor changes associated with dementia.
The team evaluated white matter lesions, which reflect damage to the brain’s small blood vessels and are commonly associated with vascular dementia. They also measured amyloid beta and tau—two hallmark proteins of Alzheimer’s disease—to determine whether lifestyle and metabolic risk factors influenced their accumulation over time.
Vascular risk factors accelerate brain damage
The study found that most modifiable cardiovascular risk factors—including smoking, cardiovascular disease, elevated cholesterol and high blood pressure—were significantly associated with faster progression of white matter damage.
White matter lesions develop when the brain’s small blood vessels become damaged, disrupting communication between brain regions and reducing blood flow. These changes are considered one of the main drivers of vascular cognitive impairment and vascular dementia.
The findings strengthen decades of research showing that maintaining healthy blood vessels benefits not only the heart but also long-term brain health.
Diabetes and body weight linked to Alzheimer’s biomarkers
The researchers also identified early associations between metabolic health and Alzheimer’s-related brain changes.
Participants with diabetes showed greater accumulation of amyloid beta, the protein that forms plaques characteristic of Alzheimer’s disease. Meanwhile, individuals with a lower body mass index (BMI) experienced faster accumulation of tau, the protein that forms neurofibrillary tangles closely linked to cognitive decline and disease progression.
The authors emphasize that these findings should be interpreted cautiously, as larger and longer-term studies are needed to confirm whether these relationships are causal.
Why prevention matters
Scientists increasingly recognize that dementia rarely results from a single disease process. Many older adults develop both vascular damage and Alzheimer’s pathology simultaneously, meaning multiple biological mechanisms often contribute to cognitive decline.
Because vascular health influences overall brain health, reducing cardiovascular and metabolic risk factors may lessen the total burden of brain injury—even among people with a genetic predisposition to Alzheimer’s disease.
Public health experts estimate that approximately 40% to 45% of dementia cases worldwide could potentially be delayed or prevented by addressing modifiable risk factors such as controlling blood pressure, treating diabetes, quitting smoking, staying physically active, maintaining social connections and addressing hearing loss.
What people can do to reduce their risk
Researchers stress that midlife represents a particularly important opportunity for prevention, as many of the biological changes associated with dementia begin decades before memory problems become noticeable.
Regular monitoring of blood pressure, cholesterol and blood sugar, combined with regular physical activity, a balanced diet, adequate sleep and smoking cessation, can help reduce damage to the brain’s blood vessels and support healthy aging.
Although age and genetics remain major risk factors that cannot be changed, accumulating evidence suggests that healthy lifestyle habits can delay the onset of dementia symptoms or reduce their severity.
The Swedish study adds further support to a growing consensus that brain health, cardiovascular health and metabolic health are deeply interconnected. Protecting the heart and blood vessels throughout midlife may also be one of the most effective ways to protect the brain later in life.
