The findings suggest yet another reason for keeping blood pressure, also known as hypertension, under control, the researchers said.
"Maintaining good vascular health by avoiding or controlling diseases like hypertension has important benefits beyond keeping your heart healthy. It may promote good brain health as we age," said lead researcher Karen Rodrigue, an assistant professor of behavioral and brain sciences at the University of Texas at Dallas.
People at risk for Alzheimers disease
This is especially so for people who are genetically at risk for Alzheimers disease, the study suggested. "Keeping good vascular health may limit or delay the brain changes associated with Alzheimer's disease and other aging-related neurological deterioration," Rodrigue said.
No cure exist for Alzheimer's, and experts anticipate that by 2050 the number of Americans with the brain disease will approach 14 million if no progress is made.
The study of nearly 120 adults found that people with this genetic risk factor for Alzheimer's disease - called an apolipoprotein E 4 allele - plus untreated high blood pressure have more beta-amyloid plaques compared to those with just one or neither of these risk factors.
One expert said the findings have important implications.
"This is good news," said Dr Sam Gandy, associate director of the Mount Sinai Alzheimer's Disease Research Center in New York City.
"This means that yet another simple intervention - here, blood pressure control, but think also of physical exercise - can have an important impact on dementia risk and rate of progression," Gandy said. "We must not overlook these simple effective interventions while developing new therapies."
How the study was done
For the study, which was published online March 18 in the journal JAMA Neurology, the researchers looked at 118 people with normal brain function who were between 47 and 89 years old. They divided the patients into those with high blood pressure and those without high blood pressure, and those with and without the genetic risk factor for Alzheimer's. The participants also were given brain scans to look for plaques.
The researchers found people with both high blood pressure and the genetic risk factor had significantly more brain plaque than those with only one or no risk factors.
Moreover, those with the highest blood pressure and the gene mutation tended to have the most plaque, they found. The study did not, however, prove a cause-and-effect relationship between high blood pressure, this genetic mutation and increased brain plaque.
High blood pressure is highly responsive to lifestyle changes and medical treatment, and it may provide a future target for delaying or preventing Alzheimer's disease, the researchers noted.
For more information on Alzheimer's disease, visit the Alzheimer's Association.