People taking common blood pressure- lowering beta blockers are less likely to experience brain changes that can lead to Alzheimer's disease and other dementias, a study suggests.

The new study included 774 elderly Japanese-American men who took part in the Honolulu-Asia Aging Study. Autopsies had been performed on the men after their death.

The findings show that levels of Alzheimer lesions were about half or less in men who were taking beta blockers compared to men whose hypertension was untreated.

The study showed that of the 774 men, 610 had high blood pressure or were being treated with medication for high blood pressure. Of the 350 patients who were being treated with medication for high blood pressure, 15 percent received only a beta blocker drug, 18 percent received a beta blocker plus one or more other medications and the rest of the men received other blood pressure drugs.

Researchers found that while all types of blood pressure treatments were significantly better than no treatment, men who had received beta blockers as their only blood pressure medication had fewer abnormalities in their brains compared to men who had not been treated for their hypertension, or those had taken other blood pressure medications

Researchers added that the brains of men who were on beta blockers in combination with other blood pressure-lowering medications also had fewer brain abnormalities, but the benefit was not as significant as in the men who only took beta-blockers.

Researchers said they had adjusted for confounding factors like the men's age, their blood pressure levels at the beginning of the study, their test score and other factors.

The brain abnormalities researchers examined in the study included two distinct types of brain lesions: lesions that indicated Alzheimer's disease and microinfarct lesions, usually attributed to tiny, multiple, unrecognized strokes.

Researchers noted that study participants who had taken beta blockers alone or in combination with other blood pressure drugs had significantly less shrinkage in their brains.

"With the number of people with Alzheimer's disease expected to grow significantly as our population ages, it is increasingly important to identify factors that could delay or prevent the disease," study author Dr. Lon White, of the Pacific Health Research and Education Institute in Honolulu, said in a statement. "These results are exciting, especially since beta blockers are a common treatment for high blood pressure."

Researchers note that previous studies have found that high blood pressure in midlife is a strong risk factor for dementia.

It is important to note that while the latest study showed an association between beta blockers and a reduced risk of brain changes linked to Alzheimer's, the study did not prove a cause-and-effect link.