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," 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 said.
According to the researchers, the study was 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.
Yasar and her colleagues conducted a "post-hoc" analysis of information gathered originally in the so-called Ginkgo Evaluation of Memory Study (GEMS) study.
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 suggested 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 study is published in the journal Neurology.