Common BP Drugs Tied to Lower Risk of Alzheimer's
Since some classes of meds had the effect but others didn't, more than just blood pressure may be at work
High blood pressure is a known risk factor for long-term thinking and memory problems, said Dr. Matthew McCoyd, assistant professor of neurology at Loyola University Medical Center in Chicago.
"High blood pressure increases the risk of small vessel ischemic disease, in which the small blood vessels in the brain get smaller and tighter," said McCoyd, who was not involved in the study. "This can lead to a number of problems with [thinking and memory]." A reduction in blood pressure can reduce injury to the part of the brain involved with memory, he said.
Still, if reductions in blood pressure were at the root of the drugs' benefit, then all blood pressure medications should have lowered patients' risks for Alzheimer's disease. But not all classes of these drugs had a protective effect, according to the research.
"We did not find any beneficial effect from calcium channel blockers, which was surprising and disappointing," Yasar said. Beta-blockers also were not associated with a reduced risk for Alzheimer's dementia, she said.
Prior studies have suggested that a specific subgroup of calcium channel blockers might still have a protective effect. "It's not a finished story," Yasar said. "There is something to it, but a larger sample size is needed for an analysis of this subgroup."
She also said the study was limited by the fact that the data was collected to assess the effects of ginkgo biloba. As a result, the researchers were not able to determine if the patients took their blood pressure medication as prescribed or if they had used these drugs in the past.
So the question remains: Do certain blood pressure medications reduce the risk for Alzheimer's dementia due to a lowering of blood pressure, or is something else going on?
"The inherent overall health benefit of these medications isn't as clear independent of high blood pressure," McCoyd said. "Do these drugs provide additional benefits in terms of brain health? If that's the case, patients at high risk for brain disease, particularly dementia, may benefit from repurposing these medications."
Blood pressure drugs are already used to treat other conditions independent of blood pressure, such as tremor and headache, McCoyd said. "With so many people affected by [thinking and memory] changes, using these drugs to prevent or delay dementia would probably have the greatest social impact."