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
By Mary Elizabeth Dallas
THURSDAY, Oct. 24 (HealthDay News) -- People who take certain commonly used blood pressure medications have a significantly lower risk for Alzheimer's disease than those who don't, a new study suggests.
Although it remains unclear exactly how drugs such as ACE inhibitors or diuretics might protect the brain, researchers say these new findings could lead to a better understanding of Alzheimer's and new treatments to slow or delay the progression of the memory-robbing disease.
"We found a risk reduction by 50 percent. That tells you there must be something there," said study leader Dr. Sevil Yasar, an assistant professor of medicine in the department of geriatric medicine and gerontology at the Johns Hopkins University School of Medicine.
The study involved information compiled from more than 2,200 older adults between 75 and 96 years of age. They had originally enrolled in an observational study examining whether the herb ginkgo biloba could reduce the risk of Alzheimer's.
The answer to that question was no, but the researchers were able to use the data already collected to conduct a separate analysis on the protective effect of some commonly prescribed blood pressure drugs, including diuretics, ARBs and ACE inhibitors.
The study, published recently in the journal Neurology, showed that regular use of these medications cut the risk of Alzheimer's dementia by at least half.
These drugs are used by millions of older Americans. For example, Lasix is one of the most commonly prescribed diuretics. Examples of ACE inhibitors include Lotensin, Capoten and Vasotec. Teveten and Avapro are two commonly used ARBs.
The researchers said diuretics, which are the first-line treatment for high blood pressure, also were linked to a 50 percent lower risk of Alzheimer's disease among participants who were already showing signs of "mild cognitive impairment" -- the slight impairment in thinking and memory that is often a precursor to Alzheimer's.
Exactly how these drugs reduced the risk for Alzheimer's dementia, however, is still unclear. One theory is that the protective effect is the result of lower blood pressure.
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.