During the study, they found that these drugs are associated with a striking decrease in the occurrence and progression of the disease.
Using data from the Decision Support System Database of the U.S. Department of Health System Veterans Affairs, researchers looked at records from patients using ARBs, and compared them with subjects who had a similar health status, but were taking different medications.
They found that patients taking ARBs had about a 35-40 percent lower chance of getting Alzheimer's disease or dementia.
The researchers also examined patients who were already suffering from Alzheimer's disease or dementia, and found those taking ARBs for hypertension had up to a 45 percent lower chance of developing delirium, being admitted to nursing homes or dying.
Patients who appeared to benefit particularly well from use of ARBs were those who had experienced strokes before or during the course of their illness.
According to the researchers, these results suggest that ARBs might protect against developing Alzheimer's disease and dementia.
"For those who already have dementia, use of ARBs might delay deterioration of brain function and help keep patients out of nursing homes," said lead presenter Benjamin Wolozin, MD, PhD, a professor of pharmacology at BUSM.
"The study is particularly interesting because we compared the effects of ARBs to other medications used for treating blood pressure or cardiovascular disease. This suggests that ARBs are more effective than other blood pressure and cardiovascular medications for preventing Alzheimer's disease or dementia," he added.
Researchers are not unsure why ARBs might be so beneficial, but they believe one possibility suggested by prior studies on animal models is that ARBs help prevent nerve cell injury from blood vessel damage or help promote nerve cell recovery after blood vessel damage.
Damage to blood vessels is thought to reduce brain capacity and promote dementia, so reducing this damage might prevent the occurrence or progression of dementia.
The study will be presented at the 2008 International Conference on Alzheimer's disease in Chicago.