Dementia is often associated with aging and genetics, but those are only part of the picture.
Researchers estimate that a large share of dementia cases may be connected to factors that people can potentially change, such as smoking and high blood pressure.
New research from Lund University in Sweden helps explain how some of these risks may affect the brain long before memory problems begin.
Dementia is not one single disease. It is a broad term for serious problems with memory, thinking and everyday functioning that can arise from different diseases.
Alzheimer’s disease is the most common cause, while vascular dementia develops when blood vessels and blood flow in the brain are damaged.
The two conditions can also occur together. In older adults, it is common to find several kinds of brain damage at the same time rather than one perfectly separate disease. This is one reason protecting blood vessel health may also matter for people who are worried about Alzheimer’s disease.
The Lund University researchers studied almost 500 people who had an average age of about 65. None showed signs of cognitive impairment when the research began. The participants were followed for four years so scientists could watch for gradual changes inside the brain.
The study examined both risks that cannot be changed and those that potentially can. Age, sex and inherited genes belong to the first group. Smoking, high blood pressure, cardiovascular disease, high levels of fats in the blood and some metabolic health problems are among the factors that may be reduced or better controlled.
Rather than simply waiting to see who developed dementia, the researchers measured biological changes that can appear years earlier. They looked at the brain’s white matter, which contains bundles of nerve fibers that allow different brain regions to communicate. Damage in this tissue is often connected with disease in the brain’s small blood vessels.
The team also measured amyloid beta and tau. These are proteins strongly associated with Alzheimer’s disease. Abnormal amyloid can collect into plaques between brain cells, while abnormal tau can form tangles inside cells and interfere with their normal function.
The clearest pattern involved vascular health. Smoking, cardiovascular disease, high blood lipids and high blood pressure were among the modifiable factors associated with damage to blood vessels in the brain. They were also linked with faster growth of white matter changes over the four-year period.
This finding is important because the brain depends on a constant supply of oxygen and nutrients from the blood. Long-term high blood pressure can damage small vessels, while smoking can harm vessel walls and affect circulation. Over time, repeated injury may damage brain tissue and contribute to problems with thinking and memory.
The study also found possible links with Alzheimer’s-related proteins. Diabetes was associated with greater accumulation of amyloid beta. People with a lower body mass index, or BMI, appeared to accumulate tau more quickly.
Those findings require particular caution. An association does not mean diabetes directly caused amyloid buildup, nor does it mean having a low body weight causes Alzheimer’s disease. Body weight can change for many reasons, including changes that occur during the early stages of illness, so more research is needed to understand the direction of these relationships.
The results highlight an important difference between Alzheimer’s disease and vascular dementia. Many familiar lifestyle and cardiovascular risks appeared to have especially clear relationships with blood vessel damage rather than with the main Alzheimer’s proteins. This gives researchers a more detailed view of what different risk factors may actually be doing inside the brain.
At the same time, the distinction is not absolute. A person may have amyloid and tau changes together with damaged blood vessels, and these problems may combine to reduce the brain’s ability to cope. Preventing one form of damage could therefore still delay symptoms even if another disease process is already developing.
This provides a practical reason to manage high blood pressure, avoid smoking and take cardiovascular health seriously throughout adulthood. Regular physical activity, treatment of diabetes and high cholesterol when needed, and a generally healthy lifestyle may protect the brain as well as the heart. No single habit can guarantee that dementia will be prevented.
The study has several strengths, including following cognitively healthy people over time and measuring actual biological changes rather than relying only on later dementia diagnoses. Separating white matter damage from Alzheimer’s-related proteins also allowed the researchers to ask more specific questions about how individual risks may operate.
However, the research remains observational. It can show that certain risk factors and brain changes occur together, but it cannot prove that changing one factor will directly prevent a particular form of dementia. The group of almost 500 participants is also relatively modest, and some findings, especially those involving diabetes, BMI, amyloid and tau, need confirmation.
The research from Lund University therefore adds detail rather than offering a simple formula for preventing dementia. Its strongest message is that risks affecting the heart and blood vessels also leave measurable marks on the brain. Because many older people develop mixed forms of brain disease, improving vascular and metabolic health may reduce part of the overall burden even when Alzheimer’s-related changes cannot be completely avoided.
Overall, the findings support the idea that dementia prevention should begin before symptoms appear.
People cannot change their age or genes, but some sources of brain damage may be reduced through treatment and healthier habits. Understanding which risk factors affect which disease processes could eventually allow doctors to give more precise advice for protecting the aging brain.
If you care about brain health, please read studies that eating apples and tea could keep dementia at bay, and Olive oil: a daily dose for better brain health.
For more health information, please see recent studies what you eat together may affect your dementia risk, and time-restricted eating: a simple way to fight aging and cancer.
Source: Lund University.
