Principal investigator George Howard of the University of Alabama in Birmingham says that those having the highest stroke risk have an accelerated rate of cognitive decline.

The difference in the annual rate of cognitive decline between a person with a 2 percent chance of a stroke in the next 10 years and a person with at 22 percent chance was 95 percent as great as the average rate of cognitive decline, the study said.

Howard suggests that this difference in the risk of a stroke roughly doubles the normal rate of decline.

The study involved 17,000 participants with an average age of 65.9 and who had an average systolic blood pressure of 127.9. Fifty-six percent of them had hypertension, 19.3 percent had diabetes, 21.9 percent suffered from heart disease; 6.5 percent had left ventricular hypertrophy -- thickening of your heart muscle -- and 13.1 percent smoked.

The findings were reported at the American Stroke Association's International Stroke Conference at New Orleans.