A study released Monday ties high blood pressure to memory problems in people over age 45.

The study found that people with high diastolic blood pressure, which is the bottom number of a blood pressure reading, were more apt to have thinking or “cognitive” impairment, or problems with their memory, than people with normal diastolic blood pressure readings.

For every 10 point increase in the reading, the likelihood of a person having thinking problems was seven percent higher. The results held up after the researchers adjusted for other factors that could affect cognitive abilities, such as age, smoking status, exercise level, education, diabetes or High cholesterol.

The findings, reported in the August 25th issue of the journal Neurology, stem from an analysis of data for 19,836 people in a long-term study.

A total of 1,505 of the participants, or 7.6 percent, had cognitive problems, and 9,844, or 49.6 percent, were taking medication for high blood pressure. High blood pressure is defined as a reading equal to or higher than 140/90 or taking medication for high blood pressure.

After adjusting for a variety of factors, higher diastolic blood pressure was directly associated with an increased risk of cognitive trouble as seen on standard tests, Dr. Georgios Tsivgoulis, from the University of Alabama, Birmingham, and colleagues report.

“It’s possible,” Tsivgoulis noted in a statement, “that by preventing or treating high blood pressure, we could potentially prevent cognitive impairment, which can be a precursor to dementia.”

Research has shown that high diastolic blood pressure can weaken small arteries in the brain, which can damage the brain.

In a statement, Dr. Walter J. Koroshetz, deputy director of the National Institute of Neurological Disorders and Stroke, said: “These latest data suggest that higher blood pressure may be a risk factor for cognitive decline, but further studies will be necessary to understand the cause-effect relationship.”

SOURCE: Neurology, August 25, 2009.