Mild hypertension may protect cognitive ability in independent people over age 70 years
Mild hypertension may protect cognitive ability
in independent people over age 70 years, according to an article
in the October issue of the American Journal of Hypertension.
Israeli researchers studied 142 men and 353
women, 51.1 percent of whom were actively receiving hypertension
treatment. Of the total of 495 people, 385 completed the study.
Of these subjects, 36 had normal blood pressure, 74 had normalized
hypertension, 103 had untreated hypertension, and 172 had treated
but uncontrolled hypertension. The mean age of subjects was 76.5
year, but the people with normal blood pressure were younger than
the people in the other groups.
"As expected at this age group, most
of the respondents (71.5 percent) were women, and less than half
(44.3 percent) were currently married," the researchers reported.
"Some three fifths continued their education beyond high school."
All 4 groups completed a battery of cognitive
tests that measured memory, concentration, visual retention, verbal
fluency and the mini-mental state examination. Of the 5 cognitive
domains tested, only verbal fluency was not related to hypertension
status.
"After adjusting for confounding variables,
treated but uncontrolled hypertensives performed significantly better
than at least one of the other groups, and normotensives performed
poorest," the researchers said. "It is worth noting that
normalized hypertensives generally performed better than normotensives,
but the differences were not statistically significant.
"Systolic and diastolic blood pressure
were related to memory, visual retention, and moderate concentration,"
the authors explained. "Systolic blood pressure values were
also positively related to mini-mental state examination scores."
The mean blood pressure of people with treated
but uncontrolled hypertension, the study group with the highest
cognitive scores, was 158.6/85.4 mm Hg, which was within the hypertension
treatment values recommended by the World Health Organization until
the 1990s.
"Examining blood pressure values as a
continuous variable enabled us to search for various models of relationship
with cognitive functioning," the authors wrote. "We found
support for the hypothesis that the association between blood pressure
and different dimensions of cognition take on different patterns.
"Thus, mini-mental state examination
scores and the lighter concentration task were linearly related
to blood pressure, whereas memory and visual retention improved
with an increase in blood pressure up to a point beyond which cognitive
performance leveled or even reversed."
The authors concluded that the benefits of
reduced blood pressure in the elderly "entail cognitive costs,
and these costs may vary from one cognitive domain to the other.
Practitioners will have to provide their patients with complicated
information, and help them reach educated decisions regarding their
choices."
"The study by Paran and colleagues counters
conventional medical science beliefs that hypertension accelerates
age-related mental decline," said Michael A. Weber, MD, an
editor of the American Journal of Hypertension. "Previous studies
yielded mixed and inconsistent results but Paran and colleagues
found support for the hypothesis that the association between blood
pressure and different dimensions of cognition take on different
patterns.
"The results of this Israeli study could
present a dilemma for physicians to choose between cardiovascular
health and cognitive health in treating elderly people with high
blood pressure," he added. "Further study is required
to weigh the proven longevity benefits of blood pressure control
with the new finding of cognitive protection. Until further evidence
comes along, it would be most prudent for clinicians to achieve
currently recommended treatment goals in their patients."
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