November 7th, 2011
04:44 PM ET
If you’re at risk for a stroke, you're more likely to suffer from mental decline, according to a study published Monday in the journal Neurology.
“Our take-home message is identifying and treating high blood pressure is very important in preserving brain health,” said Dr. Frederick. W. Unverzagt, professor of psychiatry at Indiana University School of Medicine.
Unverzagt and his colleagues found high blood pressure and other risk factors including diabetes, cigarette smoking and prior heart disease were good predictors of those most likely to develop cognitive impairment. Each 10mm increase in systolic blood pressure (the top number) increased the risk by 4%, the study found.
Age was also a significant risk factor. Each decade doubled the risk of cognitive impairment, similar to the risk of stroke.
The National Institutes of Health-funded study followed more than 23,000 people 45 and older for an average of four years. During that time, 1,907 developed significant cognitive impairment.
The group suffering mental decline during the study was significantly older and more likely to be male, African American, living in the Stroke Belt and less educated.
The Stroke Belt consists of North Carolina, South Carolina, Georgia, Alabama, Mississippi, Tennessee, Arkansas, and Louisiana. People living in the stroke belt are more likely to die from a stroke than people living in other parts of the country.
Investigators determined cognitive impairment using a simple telephone test asking subjects for the year, month and day of the week, and also testing their ability to recall three words given to them after a short delay. Each correct answer was worth one point.
Participants who score five or six at the start of the study were retested annually. Scores of four or lower were considered cognitive impairment.
The study didn’t do any brain imaging, but Unverzagt said he suspects the people who showed a mental decline suffered from micro or mini strokes. These are tiny interruptions in blood flow to the brain.
A full-fledged stroke occurs when the blood supply to part of the brain is disrupted, depriving brain tissue of oxygen and killing brain cells. A stroke often results in dramatic symptoms like numbness on one side of the body or profound problems with memory, language, speech or vision.
Stroke, which affects 795,000 Americans every year, is the third leading cause of death in the United States and the leading cause of disability.
The results were part of the ongoing Reasons for Geographical and Racial Differences in Stroke (REGARDS) study. Participants represent about 1,600 of the 3,000 counties in the United States.
George Howard, principal investigator for REGARDS, said African Americans are more likely to suffer from strokes overall and almost twice as likely as whites to have a stroke before age 65. The study, which began in 2003, is trying to decipher the causes for racial and regional disparities in stroke.
Neurology is published by the American Academy of Neurology.
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