Preventing Second Stroke May Stave Off Dementia

ByABC News
September 23, 2009, 8:18 PM

Sept. 24 -- WEDNESDAY, Sept. 23 (HealthDay News) -- The way to reduce the chances of developing dementia such as Alzheimer's disease after a stroke is to prevent a second stroke by concentrating on all the known stroke risk factors, a new British study suggests.

Two major findings emerged from an analysis of 30 previous studies that involved more than 7,500 people who had suffered a stroke, said Dr. Sarah Pendlebury, a senior clinical fellow at the Stroke Prevention Research Unit of John Radcliffe Hospital in Oxford and lead author of a report published online Sept. 23 in The Lancet Neurology.

"First, there is a clear relationship between having multiple strokes and the risk of dementia," Pendlebury said. "If someone has multiple strokes at the same time, that person has a strong risk of becoming demented in the first month."

"Second, the data suggest that the presence of complications after stroke -- such as hypertension [high blood pressure], low oxygen saturation, cardiac events and seizures -- also increases the risk of developing dementia."

Because of this, Pendlebury said, the focus of stroke treatment units should be on all the risk factors for stroke. "So, to prevent worsening of damage to the brain, the patient must be maintained in as stable a condition as is possible," she said. "We must prevent either high or low blood pressure and maximize all other secondary prevention measures."

The study found that dementia rates in the first year after a stroke vary widely, ranging from 7.4 percent in population-based studies of stroke victims who did not previously have dementia to 41.3 percent in hospital-based studies that included people who had signs of dementia before a stroke.

But the study's conclusion that the risk of dementia was associated with the risk and number of strokes, rather than underlying risk factors for cardiovascular diseases, was contested in an accompanying editorial by Dr. Michael G. Hennerici, chairman of neurology at the University of Heidelberg in Germany.