Dementia is one of the biggest health challenges facing aging populations around the world. It affects memory, thinking, behavior, and the ability to carry out everyday tasks.
As people live longer, the number of dementia cases continues to rise, creating an urgent need to understand who is at risk and why.
Scientists know that genetics can influence dementia risk. The best-known example is a gene variant called APOE ε4, which significantly increases the likelihood of developing Alzheimer’s disease. Yet researchers believe that many other genes, each contributing only a small effect, may also influence dementia in ways that are not fully understood.
A new study published in Neurology explored this possibility by examining genes linked to heart and metabolic health. The findings suggest that people who inherit more genetic variants associated with higher pulse pressure may face a slightly greater risk of dementia-related death later in life.
The research was conducted by scientists led by Dr. Laura M. Raffield at the University of North Carolina at Chapel Hill. The team focused on a concept called polygenic risk, which looks at the combined effects of many genes rather than a single genetic mutation.
Most diseases are not caused by one gene alone. Instead, hundreds or even thousands of genetic differences can each contribute a tiny amount to a person’s overall risk. By adding these effects together, researchers can create a polygenic risk score that estimates an individual’s inherited tendency toward a particular condition.
The study included 8,818 adults with an average age of 64 years. Researchers followed them for many years, collecting information about cognitive health and causes of death.
Participants underwent genetic testing, allowing scientists to calculate risk scores for several cardiometabolic conditions. These included high blood pressure, cholesterol levels, triglycerides, type 2 diabetes, stroke, coronary artery disease, atrial fibrillation, blood clots, and pulse pressure.
Pulse pressure is the difference between the upper and lower numbers in a blood pressure reading. Although it receives less attention than overall blood pressure, it can provide important information about the health of blood vessels. Higher pulse pressure often reflects stiff arteries or other cardiovascular problems.
During the study period, participants completed cognitive testing every one or two years. Researchers monitored changes in memory and thinking abilities and identified cases of cognitive impairment. They also reviewed national death records to determine whether dementia was listed as a cause or contributing factor in deaths.
Over time, 619 participants developed cognitive impairment, while 456 individuals had dementia recorded as a contributing cause of death.
After adjusting for age, sex, and other important factors, the researchers discovered that people with the highest genetic risk for elevated pulse pressure had a 16% higher risk of dementia-related death. This was the strongest relationship found among all the cardiometabolic genetic scores examined.
The researchers were surprised that other genetic risks, including those related to diabetes, stroke, and coronary artery disease, did not show similarly strong associations. This suggests that pulse pressure may have a unique connection with dementia progression.
One possible explanation is that blood vessel health plays a crucial role in maintaining brain function. The brain depends on a constant supply of oxygen and nutrients delivered through a network of tiny blood vessels. If those vessels become damaged or less flexible over many years, brain cells may become more vulnerable to injury and degeneration.
However, the researchers stress that the findings do not prove cause and effect. Having genetic variants associated with higher pulse pressure does not guarantee that someone will develop dementia. Many environmental and lifestyle factors, including diet, exercise, smoking, education, and overall health, also influence dementia risk.
The study has several strengths, including its large number of participants and long-term follow-up. However, it also has limitations. Dementia is not always recorded accurately on death certificates, which means some cases may have gone unrecognized. In addition, the observed increase in risk was relatively modest.
From a broader perspective, the findings reinforce the growing understanding that cardiovascular health and brain health are closely connected. The research suggests that some genetic pathways influencing blood vessel function may also affect how dementia develops in later life.
The study offers valuable insights but should not be interpreted as proof that pulse pressure genes directly cause dementia. Instead, it highlights an area that deserves further investigation.
Future research may help scientists better understand the biological links between the heart, blood vessels, and brain, potentially leading to new strategies for preventing dementia and improving healthy aging.
If you care about brain health, please read studies about inflammation that may actually slow down cognitive decline in older people, and low vitamin D may speed up cognitive decline.
For more health information, please see recent studies about common exercises that could protect against cognitive decline, and results showing that this MIND diet may protect your cognitive function, prevent dementia.
Source: University of North Carolina at Chapel Hill.
