Blood Pressure Drop May Signal Dementia
Augusta Chronicle, The - July 09, 2004
A substantial drop in systolic blood
pressure may be a warning signal for Alzheimers
disease and dementia in some elderly people, according
to a new study.
Swedish scientists report today in Stroke, a journal
of the American Heart Association, that a drop of
15 millimeters of mercury or more in the systolic
reading of people 75 and older who started with systolic
pressures of 160 or less was linked to a threefold
increase in the risk of developing Alzheimers
or other types of dementia.
The same decrease of 15 points or more in the systolic
(the top number in blood-pressure readings) level
in patients who already had vascular problems such
as stroke or diabetes increased the risk of Alzheimers
by 2.4 times and the types of all dementia by 2.5
"Our findings imply that poor blood flow to the
brain, resulting from an extensive decline in blood
pressure, may promote the dementia process,"
said Dr. Chengxuan Qiu, an epidemiologist at the Karolinska
Institute in Stockholm who was lead author of the
But he cautioned that because so few studies have
addressed the link between blood-pressure decline
and dementia, the findings must be verified. "We
have to consider that patients with dementia experience
a decline in blood pressure for some years before
diagnosis, which continues to decline after the onset
of dementia," said Dr. Laura Fratiglioni, a professor
at the institute who led the project.
Earlier studies have shown that high blood pressure
in middle age is associated with increased risk of
dementia and Alzheimers later in life, but studies
of older people have been conflicting. The Karolinska
researchers themselves have suggested in the past
that both high and low blood pressure may damage cognitive
ability in the elderly.
For the latest study, the researchers followed 947
people age 75 and older who had no evidence of dementia
when they entered the project, and underwent physical
exams including blood-pressure testing. This was repeated
three and six years later.
At the end of three years, 147 patients were diagnosed
with Alzheimers and 39 with other dementia;
at six years, the researchers found 91 more had Alzheimers
and 27 more had other types of dementia.
There was no difference in blood-pressure levels among
the patients at the start, but those who experienced
a systolic decline during the study were more likely
to be among those diagnosed with dementia later.
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