Taking care of your heart and blood vessels in middle age may also help protect your brain for many years.
A large study found that people without high blood pressure, diabetes or current smoking in midlife lived nearly 13 years longer without dementia than people who had all three risk factors.
The findings offer a different way to think about dementia prevention. Instead of asking only whether someone will eventually develop dementia, the researchers asked how many years of life a person could expect to spend without the condition.
Dementia is a general term for serious problems with memory, thinking and everyday functioning. Alzheimer’s disease is the most common cause, but damage to the blood vessels that supply the brain can also contribute to dementia and can occur alongside Alzheimer’s-related changes.
Healthy blood flow is essential because the brain needs a steady supply of oxygen and nutrients. Over many years, high blood pressure, diabetes and smoking can damage blood vessels and may increase the chance of stroke, small areas of brain injury and other changes linked to declining thinking skills.
These three risks are especially important because they can often be prevented, treated or changed. High blood pressure and type 2 diabetes commonly appear during middle age, while stopping smoking can improve health at almost any age.
For the study, researchers analyzed information from the long-running Atherosclerosis Risk in Communities study in the United States. The project began decades ago and has followed thousands of adults as they moved from middle age into later life.
The new analysis included 12,409 people who were free of dementia when their midlife health was assessed. Their average age was about 56, and researchers recorded whether they had high blood pressure, diabetes or were currently smoking.
Participants were followed for a median of about 26 years, with dementia tracked through 2022. This unusually long follow-up allowed the researchers to estimate how many years people lived without dementia between ages 55 and 95.
The differences were substantial. People with none of the three risk factors at midlife were estimated to have 30.1 dementia-free years after age 55, compared with 17.5 years among people who had all three.
There was also a clear pattern between these two groups. People with one risk factor had fewer dementia-free years than those with none, while people with two did worse again, suggesting that the combined burden of poor blood-vessel health matters.
By age 85, only about 7% of participants who had all three risk factors were still alive without dementia. In comparison, about 35% of those who began with none of the three risks remained dementia-free at that age.
The group with all three risk factors also had a much higher rate of dying before developing dementia. This point is important because a lower recorded lifetime chance of dementia can sometimes occur simply because people die earlier from other diseases.
Women had more dementia-free years than men at every level of vascular risk. Black participants had fewer dementia-free years than white participants, particularly when several risk factors were present, although such differences can reflect many health, social and economic influences rather than biology alone.
The research was published in Neurology Open Access. The work was led by researchers associated with NYU Langone Health and used data from the major U.S. Atherosclerosis Risk in Communities study.
The findings support a practical message: protecting blood vessels in midlife may protect the brain as well. Not smoking, staying physically active, eating a healthy diet and getting appropriate treatment for high blood pressure or diabetes can improve cardiovascular health and may also reduce factors linked to dementia.
However, the study cannot prove that eliminating these three risks will give an individual exactly 13 extra dementia-free years. It was an observational study, so other differences between participants may have contributed to the results, and the researchers summarized vascular health using only three major risk factors.
Another limitation is that the risk factors were assessed at a particular stage of midlife even though people’s health can change greatly over decades. Future research could examine whether improving blood pressure, diabetes control or smoking status over time actually changes dementia-free life expectancy.
Even with these limits, the study is valuable because its message is easy to understand. Rather than presenting only percentages, it shows that midlife health may be connected with something very meaningful to people: the number of later years they may live with their memory and thinking abilities intact.
Overall, the results strengthen the evidence connecting heart health and brain health, but they should not be read as a guarantee that dementia can always be prevented. Genetics, aging and many other factors also matter, yet controlling preventable vascular risks remains a sensible way to support both longer life and healthier brain aging.
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.
Source: NYU Langone Health.
