A 26-year study dug into the data—here’s what the scientists found.
Reviewed by Dietitian Jessica Ball, M.S., RD
Key Points
- Managing blood pressure, blood sugar and avoiding smoking may add over a decade of dementia-free years.
- Midlife vascular health is key to brain health, and your health at midlife can have an impact years down the line.
- Daily habits can support vascular and brain health—start by eating more plants and exercising regularly.
Dementia affects more than 57 million people worldwide, and its causes—and effects—continue to fascinate researchers. In the U.S. alone, 42% of Americans are at risk of developing it at some point after age 55. And while risk factors such as age and genetics are out of our hands, recent research suggests that others are not.
A new study published in Neurology Open Access tracked more than 12,000 adults for 26 years and found that three common midlife conditions—high blood pressure, diabetes and smoking—had an outsized effect on how many years people lived free of dementia. People in midlife with none of the three could expect about 30 healthy brain years from age 55, while those with all three averaged just 17.5. Here’s what the researchers found and what it means for your brain health.
How Was the Study Conducted?
Researchers analyzed data from 12,409 adults enrolled in the Atherosclerosis Risk in Communities (ARIC) Study, a long-running, community-based cohort that has tracked participants since 1986. All participants were free of dementia at the beginning of the study and ranged in age from 45 to 65. They were followed for a median of 26 years.
Each participant was assessed at baseline for three vascular risk factors: high blood pressure, diabetes and current smoking status. Researchers then used statistical modeling to estimate dementia-free survival from age 55 to 95. Essentially, this included how many years after age 55 a person could expect to live without a dementia diagnosis, depending on how many of those three risk factors they had at midlife.
What Did the Study Find?
Researchers observed that participants with none of the three risk factors could expect about 30.1 dementia-free years from age 55. Each additional risk factor reduced that number, and those with all three averaged just 17.5 dementia-free years, for a gap of about 13 years.
The study also found significant differences across demographic groups. Women had more dementia-free years than men regardless of risk factor burden, and participants who were white averaged more dementia-free years than participants who were Black.
However, the researchers noted that the study doesn’t prove these three risk factors directly cause dementia, only that their presence in midlife was associated with fewer dementia-free years. Risk factors were also measured only once at the beginning of the study, so changes that occurred during the study (e.g., someone quitting smoking midway through or developing diabetes later in life) were not captured.
How Does This Apply to Real Life?
“Our findings argue that people need to actively avert these factors in midlife as a strategy for preserving brain health for more than a decade,” said study senior investigator Josef Coresh, MD, Ph.D., founding director of the Optimal Aging Institute at NYU Langone, in a statement. “Discovering new ways to delay dementia is crucial with 42% of Americans at risk for developing the condition at any time after age 55.”
The good news is that all three risk factors the study identified can be managed through a combination of lifestyle changes and medical care. Here are a few evidence-based strategies to consider:
- Get your blood pressure checked regularly. High blood pressure often has no symptoms, which is why it’s sometimes called a “silent killer.” Knowing your numbers is the first step. Additionally, consider reducing your sodium intake, eating more potassium-rich foods and following a plant-forward eating pattern to help support healthy blood pressure levels.
- Pay attention to your blood sugar. According to research, diabetes is one of the most modifiable dementia risk factors and is closely linked to diet. Consuming fewer added sugars, increasing your fiber intake and maintaining a healthy weight are effective strategies for managing your blood sugar.
- Quit smoking (or don’t start). Smoking is linked to accelerated brain aging through multiple pathways, including reduced blood flow to the brain and increased systemic inflammation. Quitting smoking at any age will benefit your health, but the earlier the better.
Our Expert Take
A new 26-year study published in Neurology Open Access found that adults who reached midlife without high blood pressure, diabetes or smoking could expect roughly 13 more dementia-free years from age 55 compared to those with all three risk factors. While the study can’t prove causation, the scale of the difference—more than a decade of improved brain health—highlights just how crucial midlife vascular health is for long-term cognitive health. Managing your blood pressure, keeping your blood sugar levels in a healthy range, and not smoking are among the most impactful things you can do in your 40s and 50s to protect your brain for the decades ahead.