High blood pressure can make it hard for middle-aged adults to think clearly and remember things, according to a new study.

The study found that people in their mid-40s and older with high diastolic blood pressure - the bottom number of a blood pressure reading - were more likely to have “cognitive” impairment, or problems with their memory and thinking skills, than people with normal diastolic readings.

The study, reported in the journal Neurology, involved 19,836 people age 45 and older who had never had a stroke or mini-stroke. A total of 1,505 of them (7.6 percent) had cognitive problems and 9,844 (49.6 percent) were taking medication for high blood pressure.

For every 10-point increase in the diastolic blood pressure reading, the likelihood of a person having cognitive problems was 7 percent higher, the researchers found.

The results held up after adjusting for other factors that could affect brain function, such as age, smoking status, exercise level, education, diabetes or High cholesterol.

“It’s possible that by preventing or treating high blood pressure, we could potentially prevent cognitive impairment, which can be a precursor to dementia,” Dr. Georgios Tsivgoulis, an investigator on the study from the University of Alabama at Birmingham, noted in a prepared statement.

It’s been shown, Tsivgoulis and colleagues note, that high diastolic blood pressure leads to weakening of small arteries in the brain, which can result in the development of small areas of brain damage.

SOURCE: Neurology, August 25, 2009.