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Feb. 25 - Faster Cognitive Decline in Elderly May Be Signalled by Stroke Risk Factors

Older Americans with the highest risk of stroke, but those who have never suffered a stroke, also have the highest rate of cognitive decline, researchers reported at the American Stroke Association's International Stroke Conference 2008.

"Everyone knows that people lose some cognitive function as they age," said George Howard, Dr. PH, the principal investigator of the ongoing study. "We found that people at high risk of stroke, decline twice as fast as those persons considered at low-risk."

Howard and his colleagues correlated the stroke risks of 17,000-plus study participants with the results from a simple cognitive test and found the stroke risk scores tracked closely with the average age-, race-, and gender-adjusted annual cognitive decline.

Using the Framingham Stroke Risk Function (FSRF) assessment - which uses risk factors to estimate the chance of having a stroke in the next 10 years - researchers found that those with the highest stroke risk also had an accelerated rate of cognitive decline.

"The difference in the annual rate of cognitive decline between a person with a 2% chance of a stroke in the next 10 years and a person with at 22% chance was 95% as great as the average rate of cognitive decline - suggesting that this difference in the risk of a stroke roughly doubles the normal rate of decline," Howard said.

The cognitive assessment used in this study consisted of six questions, including giving study members three common words and asking them later in the telephone call to repeat them.

"A lot of people couldn't remember the words," Howard said. "If you extrapolate these effects, our findings suggest that would be an average 8% larger increase in missed questions after 10 years in the high-risk group," he added. "That's a large difference."

Besides relating FSRF scores to cognitive decline, researchers also assessed the influence of the eight individual items that make up the FSRF. They identified three specific risk factors significantly associated with memory loss - high systolic blood pressure, diabetes, and left ventricular hypertrophy (the thickening of muscle in the heart's main pumping chamber that often results from hypertension). Diabetes was associated with about at 56% increase in the rate of cognitive decline while left ventricular hypertrophy was associated with about a 60% increase in the rate of decline. A 31 mm Hg-higher level of blood pressure was associated with a 29% increase in the rate of cognitive decline, Howard said.

Identifying the three conditions could have important implications for slowing the age-related decline in mental functioning. "Physicians and patients should be as vigilant as possible in controlling hypertension and diabetes because it may slow cognitive decline," Howard said.

Source: American Heart Association

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