|
Silent
Strokes Boost Alzheimer's Risk
Excerpt
By Linda Johnson,
AP
Here's another good reason for healthy
living: Symptomless, unnoticed strokes more than double the risk
of developing Alzheimer's disease, according to a large Dutch
study.
The researchers and other experts
said the finding suggests many people could prevent the mind-robbing
disorder by keeping their heart and blood vessels healthy by exercising,
eating a balanced diet and quitting smoking.
Elderly people who suffered tiny
"silent strokes" — detected by an MRI — had their mental
function decline more sharply and were about 2.3 times more likely
to develop Alzheimer's or other types of dementia, researchers
at Erasmus Medical Center found.
The study, the first major one
on silent strokes, was published in Thursday's New England Journal
of Medicine.
The work provides "very powerful
confirmation" of evidence linking narrowed blood vessels in the
brain, stroke and Alzheimer's, said Bill Thies, vice president
for medical and scientific affairs at the Alzheimer's Association.
"This is an extraordinarily well-done
study in a big group of people," Thies said. "They have identified
an outcome from these small (strokes) that we wouldn't have suspected."
In an editorial, Drs. John Blass
and Rajiv Ratan of Cornell University's Weill Medical College
said the study and other evidence indicate inadequate blood flow
in the brain is an underlying cause of both Alzheimer's and stroke
— and that silent stroke may be the first sign of Alzheimer's,
not just a risk factor.
Silent strokes are fairly common
in the elderly, based on MRI scans of the 1,015 people aged 60
to 90 in the study, said lead investigator Dr. Monique Breteler,
head of the Erasmus center's neuroepidemiology research group.
The scans, performed in 1995 and
1996, found brain cell damage in 217 people that indicated a silent
stroke. Over an average of 3.6 years of follow-up, 3 percent,
or 30 people, developed dementia; 26 had Alzheimer's and four
had other forms.
A stroke is a "brain attack" in
which the flow of blood and oxygen to part of the brain is interrupted.
Most often, it is caused by a blood clot or a hardening of arteries
in the brain that cuts off blood flow; this type of stroke, called
an infarct, was examined in the study.
Damage from a stroke, such as difficulty
speaking or weakness in a limb, varies with the stroke's location
and severity. But mental function often declines.
In dementia, mental ability usually
declines gradually, impairing memory, learning skills, judgment
and attention span. Alzheimer's disease, which also is linked
to excessive buildup of proteins in the brain, accounts for about
two-thirds of dementia cases.
Along with following the 1,015
patients to see who developed dementia, the researchers did a
second MRI on 619, some of whom had had additional silent strokes.
Mental decline was even more severe in those people, as well as
those who had lesions deep inside the brain from narrowed blood
vessels, Breteler said.
Because many people who did not
undergo a second MRI were in poorer shape mentally, Breteler said,
the researchers probably underestimated how much silent strokes
increase risk of dementia.
Many people with Alzheimer's have
standard risk factors for stroke and heart disease. Those include
elevated blood pressure, cholesterol and blood sugar levels; eating
a diet high in fat and low in vegetables; smoking; and getting
little or no exercise.
Getting the elderly to follow health
guidelines to reduce or eliminate those risk factors could prevent
dementia or strokes, Breteler said.
Blass and Ratan suggested the same
steps for any patients found to have had a silent stroke. They
also recommended such patients be monitored by doctors and take
baby aspirin every day.
"It's another reason for keeping
your cardiovascular system healthy," said Dr. Patrick Pullicino,
chairman of neurology and neurosciences at University of Medicine
and Dentistry of New Jersey in Newark. "This is simple, common
sense."
Pullicino, who is running a 70-center
study on preventing stroke and death in heart patients, said there
is evidence of mental impairment in elderly people with heart
failure, in which the heart can't pump enough blood and oxygen
to the brain and body.
He said when an MRI shows a patient
has had a silent stroke, doctors must determine the cause and
aggressively treat it to prevent a second stroke.
___
On the Net:
Journal: http://www.nejm.org
Alzheimer's organization: http://www.alz.org
Reference
Source 102
For more information on how to prevent other diseases, use
PreventDisease.com's "Quick
Prevention Resources".
|
