BODY & BRAIN
Lower blood pressure may aid memory
Preliminary results show the benefits of aggressive treatment
BY AIMEE CUNNINGHAM
Keeping a tight lid on blood pressure
isn’t just good for the heart. It may also
help the brain.
People given intensive drug treatment
for high blood pressure were less likely
to develop an early form of memory loss,
according to preliminary results from a
clinical trial called SPRIN T-MIND. This
approach reduced the rate of new cases
of mild cognitive impairment by around
19 percent, compared with people who
received less aggressive treatment.
And the intensely treated group developed fewer white matter lesions over
time, researchers reported July 25 at the
Alzheimer’s Association International
Conference in Chicago. White matter
lesions, which are associated with dementia, are thought to be caused by blood
vessel injuries in white matter, the part of
the brain that contains nerve fibers.
The brain research is part of SPRINT,
the Systolic Blood Pressure Intervention
Trial involving more than 9,300 participants. Some received intensive treatment
aimed at lowering their systolic blood
pressure — the pressure on artery walls
when the heart beats — below 120 millimeters of mercury; others got standard
treatment to bring it below 140.
The trial had already reported that
people who received the intensive treatment dropped their risk of heart attacks
and other cardiovascular problems by
25 percent, compared with the standard
group. The results were the basis for
more stringent blood pressure guidelines
released last year (SN: 12/9/17, p. 13).
Observational studies have shown that
people with lower blood pressure have a
lower risk of dementia, says geriatrician
Jeff Williamson of Wake Forest School
of Medicine in Winston-Salem, N.C.
SPRINT-MIND set out to test that claim.
Using memory tests, researchers
assessed the trial participants for prob-
able dementia (unable to perform daily
activities independently), early memory
loss (some difficulty functioning, but
still independent) or no impairment.
By June 2018, more than 8,600 of the
people, with an average age of 68, had
completed an assessment.
Fewer people in the intensely treated
group had early memory loss, which
is often a precursor to dementia, says
Williamson. The trial was ended early,
in 2015, due to the compelling cardio-
vascular benefits, so participants’ blood
pressure was medically managed for
only two to three years. “That’s an
encouraging message,” Williamson says.
“It doesn’t take but just a few years to see
The trial also looked at white mat-
ter lesions. These injuries in the brain
are a consequence of aging, but are also
associated with hypertension, says Ilya
Nasrallah, a neuroradiologist at the
University of Pennsylvania. Previous
work has found that white matter lesions
increase risk for dementia in people
60 and older.
About 450 participants had MRI brain
scans at the start of the trial and about
four years later. The volume of white
matter lesions increased by 0.28 cubic
centimeters over that time in the intensive treatment group and 0.92 cubic
centimeters in the standard group.
But there is evidence that the relationship between blood pressure and
brain health may change with advancing
age, says Zoe Arvanitakis, a cognitive
neurologist at Rush University Medical
Center in Chicago who was not involved
with the trial.
In adults 75 and older, past work has
found that low diastolic blood pressure — the pressure on arteries when the
heart rests between beats — increases
the risk of dementia. The age at which
people are at high risk for dementia is
older than the average age of those in the
SPRINT-MIND trial, Arvanitakis says.
“We really need to study this question in
older persons as well.” s
EARTH & ENVIRONMENT
Massive iceberg gets
stuck in Antarctica
About a year ago, an iceberg about
the size of Delaware broke off the
Larsen C ice shelf in Antarctica
(SN: 8/5/17, p. 6). And the ice chunk
hasn’t moved much since. The iceberg
traveled about 45 kilometers northeast before getting stuck behind an
elevated ice promontory called the
Bawden ice rise (as shown above in an
infrared satellite image taken July 1).
Scientists monitoring the iceberg
say it has been battering the Bawden
ice rise as winds and ocean currents
push against the iceberg. Bawden
helps stabilize Larsen C. If Bawden
were destabilized, that could lead
to the collapse of the rest of the ice
shelf, which could have implications
for sea level rise, says Earth observation researcher Anna Hogg of the
University of Leeds in England.
The iceberg may still escape if it can
twist around the tip of Bawden. Currents and winds often carry Antarctic
icebergs toward South Georgia Island
in the southern Atlantic Ocean, where
many icebergs thin out and melt away,
says glaciologist Ted Scambos of the
National Snow and Ice Data Center in
Boulder, Colo. — Leah Rosenbaum