FRIDAY, Feb. 6, 2004 (HealthDayNews) -- Common cholesterol-lowering drugs might reduce the risk of brain damage after a stroke.
The drugs, called statins, are already known to reduce the risk of having heart attacks and stroke.
This latest finding will be presented Feb. 6 at the American Stroke Association's annual meeting in San Diego.
One of the most troubling consequences of ischemic strokes, which are caused by blood clots that disrupt blood flow to the brain, are various degrees of cognitive impairment. The mildest form is called vascular cognitive impairment-no dementia (VCIND). The most severe form is known as vascular dementia, which may occur in as many as a third of stroke survivors.
Previous observational studies have suggested statins may reduce the risk of Alzheimer's disease and vascular dementia in general. The researchers behind the new study wanted to see if statins could also help in stroke-related cognitive impairment.
"We were trying to identify risk factors for cognitive impairment after a stroke and to find out if cardiovascular risk factors, which are the risk factors for the stroke itself, also play a role, protective or not, in cognitive impairment," says study leader Dr. Eugenia Gencheva, a research fellow at the University of Illinois at Chicago Center for Stroke Research.
Gencheva and her colleagues looked at 103 people who had had an ischemic stroke, the most common type of stroke. Forty-one percent had been diagnosed with VCIND and 62 had no evidence of cognitive impairment at all.
All the participants had had an ischemic stroke within the past three to six months, says study co-author David Nyenhuis, an associate professor of neurology and rehabilitation at the University of Illinois at Chicago.
The participants answered questions about risk factors for cognitive impairment and underwent neuropsychological testing. While the individuals did provide information about cholesterol levels, blood pressure and other vascular risk factors, these were not verified by blood tests.
Three factors seemed to determine the risk of cognitive impairment: education level; presence of heart disease; and a history of high cholesterol.
Once the results were adjusted for the effects of education (the more education, the less the risk of dementia), only high cholesterol remained as a statistically significant predictor of the risk for cognitive impairment.
The reason why remains unclear.
But the researchers theorize it wasn't the high cholesterol levels that protected against dementia, but the statins the people were taking to lower their cholesterol.
"Statins increase the production of nitric oxide, which relaxes blood vessels, and that may allow blood vessels to respond better to stroke and allow blood to get to the brain as well as also reduce the inflammatory response," says Dr. Robert A. Felberg, director of the stroke program at the Ochsner Foundation Clinic and Hospital in New Orleans.
While the data is intriguing, it is preliminary.
"It isn't a direct finding per se. Our patients who reported high cholesterol levels or trouble with high cholesterol were less likely to have cognitive impairment," Nyenhuis says. "We didn't ask a number of questions regarding statin use. That's something we are going to have to follow up with, although, at this point, I don't know how else this could have happened."
About 45 percent of the study participants were being treated with statins before having a stroke.
The next step is to start research focusing on statin use in stroke survivors.
"Anything that could improve outcome and cognition is good to hear," Nyenhuis says. "It's incomplete news. We're on to something but it needs confirmation."