In one study, researchers discovered that women with Alzheimer's who received
extra estrogen experienced no improvement in their mental abilities after one
year of treatment.
In another report, investigators discovered that older, dementia-free women
with relatively high levels of estradiol, a form of estrogen, did no better on
memory tests than women of the same age with the lowest levels of estradiol in
their blood.
Together, these findings suggest that both users and non-users of hormone
replacement therapy, which provides post-menopausal women with extra estrogen,
are not getting any memory boost from the female sex hormone.
Both studies appear in the February issue of the Archives of Neurology.
The most convincing evidence of the benefits of estrogen for memory comes
from studies with animals, in which researchers have shown that estrogen may
prevent the loss of cells in a part of the brain called the hippocampus, and may
help mop up damaging free radicals. The hippocampus plays a role in memory and
has been tied to the development of early Alzheimer's.
Investigations of estrogen's effect on memory in people have yielded
conflicting results, but some studies have suggested that high levels of the
hormone may protect women against memory loss and even boost verbal memory.
During one of the current studies, Dr. Monique M. B. Breteler of the Erasmus
MC in Rotterdam and her colleagues studied memory and hippocampus size in 210
elderly women and 202 elderly men, all dementia-free.
Breteler and her colleagues found that women with the highest levels of
estradiol in their blood tended to do worse on word memory tests and had smaller
hippocampi than women with the lowest levels of blood estradiol.
Hippocampal size did not differ according to estradiol levels in men, but men
with low estradiol levels also tended to perform better during memory tests than
those with higher levels of the hormone.
In a separate investigation, Dr. Leon J. Thal of the University of
California, San Diego in La Jolla and colleagues administered different doses of
the estrogen drug Premarin to 120 women with Alzheimer's disease who had
undergone hysterectomy to remove their uterus.
Thal and his colleagues found that women who received Premarin experienced a
boost in estradiol blood levels that matched the dose they were given.
However, the rise in estradiol levels was not accompanied by any changes in
mental functioning during the study period, the authors note, indicating that
extra estrogen was not improving patients' cognitive abilities.
