A new study from Johns Hopkins Bloomberg School of Public Health shows that many cases of dementia before age 80 might be preventable.
The key is to take care of common health problems that affect blood vessels, like high blood pressure, diabetes, and smoking, especially from middle age onward.
The researchers believe that up to 44% of dementia cases before 80 could be linked to these health problems.
Dementia is a condition that affects memory, thinking, and decision-making. As more people live longer, dementia is becoming more common worldwide. But scientists still don’t fully understand what causes it or how to stop it. One clue comes from looking at the health of our blood vessels—especially the tiny ones in the brain.
When these small blood vessels are damaged or blocked, they can stop delivering enough oxygen and nutrients to brain cells. This damage is known as cerebral small vessel disease, and it often leads to changes in thinking and memory that look a lot like aging or even Alzheimer’s disease.
Many people who are at risk for dementia might not even notice anything wrong at first. They might forget where they put something, mix up names, or feel mentally foggy. These problems can seem normal, especially as we get older.
But when blood vessels in the brain get worse over time, this damage can suddenly seem to show up all at once, leading to a dementia diagnosis. That’s why catching these risk factors early is so important.
Another challenge is that people often have more than one type of brain problem at the same time. For example, someone might have damage from both poor blood flow and Alzheimer’s-related brain changes.
This makes it hard to know how much dementia could be prevented by treating just one kind of issue, like blood pressure. Still, the researchers wanted to find out how big of a role these blood vessel-related risks play.
To do that, the study followed over 12,000 adults in four different parts of the U.S. for 33 years. At different times during the study, researchers checked whether participants had risk factors like high blood pressure, diabetes, or a history of smoking.
Participants were between 45 and 74 years old when these measurements were taken. The researchers then tracked who developed dementia over time using medical records and interviews with the participants or their families.
They found that the earlier these risk factors showed up, the more they mattered. For example, when people had these issues between ages 45 and 54, about 22% of dementia cases before age 80 could be linked to those problems.
This number went up to 26% for people aged 55 to 64, and jumped to 44% for those aged 65 to 74. However, for people who developed dementia after age 80, the link between these vascular problems and dementia was much weaker—only about 2% to 8%.
The study also looked at different groups of people. They found that the connection between blood vessel health and dementia risk was even stronger in people who don’t carry a gene called APOE ε4, which is a well-known genetic risk factor for Alzheimer’s.
For these people, more of the risk came from things like blood pressure and diabetes, rather than their genes. In this group, up to 61% of dementia cases between ages 65 and 74 were linked to vascular risk. The numbers were also higher for women (up to 51%) and Black participants (up to 53%).
In the end, the study shows that a large number of dementia cases—especially those before age 80—could be avoided by better managing heart and blood vessel health throughout life. This means stopping smoking, keeping blood pressure under control, and preventing or managing diabetes. These are changes that people can often make with the help of their doctors.
The findings are important because they give people and healthcare systems something to act on. While we can’t change our genes, we can make changes to our lifestyle and health care that might lower the risk of dementia.
According to the study’s authors, staying on top of these common health problems well into old age could make a big difference in whether or not someone develops dementia before age 80.
In summary, the study provides strong evidence that many cases of dementia could be delayed or prevented if people manage key health risks starting in midlife. It highlights the urgent need for public health strategies that focus on blood pressure, diabetes, and smoking—not just for heart health, but also for protecting the brain.
If you care about dementia, 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.
The research findings can be found in JAMA Neurology.
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