MONDAY, June 21, 2021 (HealthDay News) -- Older adults who use certain blood pressure drugs may retain more of their memory skills as they age, a new study suggests.
Researchers found the benefit among older people taking medications that are allowed past the "blood-brain barrier," which is a border of specialized cells that prevents toxic substances from crossing into the brain.
Those drugs include certain ACE inhibitors and angiotensin II receptor blockers (ARBs) -- two major classes of blood pressure medication.
Among nearly 12,900 study patients, those taking the brain-penetrating medications showed less memory loss over three years, versus people on blood pressure drugs that cannot cross the blood-brain barrier.
The findings add another layer to the connection between blood pressure and brain health.
High blood pressure is considered a risk factor for dementia, and there is evidence that tight blood pressure control lowers the risk of cognitive impairment -- declines in memory and thinking skills -- as people age.
The new study was published June 21 in the journal Hypertension.
It suggests that brain-penetrating medications may bring an "added benefit" beyond that of lowering blood pressure, said senior researcher Daniel Nation.
"I think this effect is independent of blood pressure control," said Nation, an associate professor at the Institute for Memory Impairments and Neurological Disorders at the University of California, Irvine.
Both ACE inhibitors and ARBs act on the body's renin-angiotensin system, which is key in blood pressure regulation.
But the brain, Nation explained, has its own renin-angiotensin system, separate from the body's. Research suggests that this system is involved in learning and memory -- and that it's "altered" in Alzheimer's disease.
No one is discounting that blood-pressure lowering benefits the brain, Nation stressed.
A 2018 trial called SPRINT-MIND found that "intensive" control of high blood pressure lowered older adults' risk of mild cognitive impairment by 19%, versus standard blood pressure control. That meant getting systolic blood pressure (the first number in a reading) below 120 mm Hg.
"We're asking, is there anything further we can do beyond aggressive control?" Nation said.
His team pulled together data from 14 previously published studies of older adults, typically in their 60s or 70s. All were taking an ACE inhibitor or ARB for high blood pressure.
Some were using medications that cross the blood-brain barrier: the ACE inhibitors captopril, fosinopril, lisinopril, perindopril, ramipril, and trandolapril, or the ARBs telmisartan and candesartan.
Overall, Nation's team found, patients on those medications had a slower decline in memory performance over three years, versus those on non-crossing blood pressure drugs.
Dr. Robert Carey, a professor of medicine at the University of Virginia, said the findings raise an "extremely important" question of whether certain blood pressure medications are better for slowing memory decline.
This study does not answer give a final answer, he said, but research should continue.
"This is something we need to pay attention to," said Carey, who helped craft the American College of Cardiology/American Heart Association guidelines on treating high blood pressure.
One big question is whether people on brain-penetrating medications ultimately have a lower risk of dementia.
"That remains unproven," Nation said.
And while study patients on those medications did modestly better on memory tests, they actually fared worse in another cognitive skill: attention.
Nation said that was a surprise finding. But, he noted, in contrast to memory performance, attention can be swayed by things such as stress and mood.
For now, Carey stressed the importance of getting high blood pressure under control "by any means" -- including various medications, diet changes, exercise and quitting smoking.
"It seems clear that blood pressure control matters in cognition," Carey said.
When doctors prescribe high blood pressure medication, he noted, they are not considering -- and likely don't know -- whether the drug crosses into the brain.
But Nation said they could take it into account, if an ACE inhibitor or ARB is being prescribed anyway.
If patients already take an ACE inhibitor or ARB that does not cross into the brain, he said, they could talk to their doctor about a switch if they are interested.
The study was funded by the U.S. National Institute on Aging and the Alzheimer's Association. The researchers report no financial conflicts of interest.
The American Heart Association has more on controlling high blood pressure.
SOURCES: Daniel A. Nation, PhD, associate professor, psychological science, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine; Robert M. Carey, MD, professor, medicine, University of Virginia School of Medicine, Charlottesville, Va., and vice chair, writing group, 2017 ACC/AHA Hypertension Guidelines; Hypertension, June 21, 2021, online