Treating high blood pressure may also decrease the risk of dementia, new research suggests. The study included 774 deceased men who had high blood pressure while alive. Autopsy results showed fewer signs of dementia in the brains of men who had been treated for the condition. They had less brain shrinkage and fewer areas of brain cell death caused by mini-strokes. They also had fewer amyloid plaques and tangles, signs of Alzheimer's disease. Treating high blood pressure can decrease the risk of strokes. But it's unclear why treatment would prevent Alzheimer's disease. Another surprise was that the men treated with beta-blockers had the healthiest looking brains. Beta-blockers are less effective than some other blood pressure medicines. But for those who used them brain damage was about half as severe as that for men who used other treatments. The study was published January 7 on the website of the American Academy of Neurology. It will be presented at the group's annual conference in March. USA Today wrote about the study.

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

It's well known that untreated high blood pressure leads to stroke, heart attack, heart and kidney failure, and early death. What's somewhat off the radar is the greater risk of memory decline and dementia from high blood pressure (hypertension).

But the relationship between function of the aging brain and higher blood pressure is not straightforward. Clearly, people with high blood pressure have an increased risk of mini-strokes. And multiple mini-strokes damage the brain. The result can be memory loss and decreased thinking ability. Doctors often refer to this condition as vascular dementia.

But why should uncontrolled high blood pressure increase the risk of Alzheimer's disease? People with Alzheimer's disease develop protein deposits in the brain called beta amyloid. Right now, there is no known biological reason for high blood pressure to cause more of these protein deposits.

The new findings of a long-term study offer interesting ideas about how blood pressure and dementia may be related. The new research was part of the Honolulu-Asia Aging Study. Researchers used autopsy results to look at differences in the brains of Japanese-American men who had high blood pressure during life. The men who took medicines to lower blood pressure had healthier-looking brains. Brain autopsies showed fewer mini-strokes in the treated men. They also had less brain shrinkage and fewer beta amyloid deposits.

One conclusion would be that the men who took drugs had better blood pressure control. But it's also possible that drugs used to treat the high blood pressure had a protective effect. One or more of the drugs may lower dementia risk for reasons unrelated to blood pressure levels.

In fact, the men who took a beta-blocker had the fewest dementia-related brain changes at autopsy. And we know today that beta-blockers are not the best blood pressure drugs. Other types of drugs lower blood pressure more effectively.

What Changes Can I Make Now?

This one study should not change how you try to achieve the best blood pressure for you. You may need to take medicine to lower your blood pressure. But lifestyle changes come first. And they will always be an important part of keeping your blood pressure in line.

Here are the basics:

• Strive for 45 to 60 minutes of exercise a day.
• Increase your overall physical activity throughout the day. For example, walk around within the office or outside your home. Take the stairs rather than the elevator.
• If needed, lose weight. Even 10 pounds can lower blood pressure significantly.
• Load up on fruits and vegetables.
• Cut back on salt.
• Get enough sleep.
• If you drink alcohol, use it in moderation. This means no more than an average of 2 drinks per day for men and no more than 1 per day for women.

What Can I Expect Looking to the Future?

Beta blockers used to be recommended as first-line drugs to treat high blood pressure. New guidelines have moved them down to second or third choices when other drugs have not done the job. However, this study suggests beta-blockers may have a role in helping to prevent dementia that is not related to lowering blood pressure. You can expect to see studies done in the future to look at this possibility.