Blood pressure drugs shown to decrease risk of Alzheimer's disease dementia

A Johns Hopkins-led analysis of data previously gathered on more than 3,000 elderly Americans strongly suggests that taking certain blood pressure medications to control blood pressure may reduce the risk of dementia due to Alzheimer's disease (AD).

In a report published in a recent edition of the journal Neurology, a team of researchers found that people over the age of 75 with normal cognition who used diuretics, angiotensin-1 receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors showed a reduced risk of AD dementia by at least 50 percent. In addition, diuretics were associated with 50 percent reduced risk in those in the group with mild cognitive impairment.

Beta blockers and calcium channel blockers did not show a link to reduced risk, the scientists reported.

"Identifying new pharmacological treatments to prevent or delay the onset of AD dementia is critical given the dearth of effective interventions to date," says the author, Sevil Yasar, M.D., Ph.D., assistant professor of medicine in the Department of Geriatric Medicine and Gerontology at the Johns Hopkins University School of Medicine. "Our study was able to replicate previous findings, however, we were also able to show that the beneficial effect of these blood pressure medications are maybe in addition to blood pressure control, and could help clinicians in selecting an antihypertensive medication based not only on blood pressure control, but also on additional benefits."

Alzheimer's disease is a rapidly increasing clinical and public health issue in the United States' aging population, and the most common cause of intellectual and social decline.

Yasar and her colleagues conducted a "post-hoc" analysis of information gathered originally in the so-called Ginkgo Evaluation of Memory Study (GEMS) study, a six-year effort to determine if use of the herb ginkgo biloba reduced AD risk. That study , a double-blind, randomized, controlled clinical trial of 3,069 adults without dementia, aged between 75 and 96 years, began in 2000 and recruited participants from four U.S. cities: Hagerstown, Md.; Pittsburgh, Pa.; Winston-Salem/Greensboro, N.C.; and Sacramento, Calif.

Yasar said that while the GEMS trial showed no benefit of ginkgo biloba in reducing incidence of dementia, information was also available among the study participants related to their use of several classes of antihypertensive drugs. Extensive studies suggest that high blood pressure is a major risk factor for dementias including AD, and there had been suggestions that drugs used to control blood pressure conferred a protective effect on the brain in addition to controlling blood pressure.

The question, she said, was which ones were associated with reduced AD dementia risk, and which were not.

Yasar and colleagues looked at 2,248 of the GEMS subjects, of them 351 reported use of a diuretic, 140 use of ARBs, 324 use of ACE inhibitors, 333 use of calcium channel blockers and 457 use of beta blockers. The average age of this group was 78.7 years, and 47 percent were women.