Common hormone therapy
doubles dementia risk
Findings from the Women's Health Initiative (WHI)
suggest that older women taking the most common form of
hormone replacement therapy are at increased risk of
developing dementia, including Alzheimer's disease. The
research, published in the May 28 issue of the
Journal of the American Medical Association,
provides further evidence that the risks of estrogen
plus progestin
outweigh the benefits.
The
Women's Health Initiative Memory Study (WHIMS), a part
of the WHI project, found that combined hormone therapy
(estrogen plus progestin under the brand name Prempro)
doubled the risk for probable dementia in women 65 and
older and did not prevent mild cognitive impairment. Of
the 4,532 women enrolled in the memory study and
monitored for approximately five years, 61 (1.3 percent)
were diagnosed with probable dementia -- of those, twice
as many (40) were taking
estrogen plus progestin compared to those (21) in the
placebo group.
"The
findings translate into 23 additional cases of dementia
for every 10,000 women annually, which means the risk to
an individual remains low," said Dr. Rebecca Jackson, an
endocrinologist and the Women's Health Initiative
principal investigator at The Ohio State University
Medical Center, who co-authored the memory study. "But
the concern over increased risk coupled with the fact
that hormone replacement therapy offers no cognitive
benefits led us to recommend that women should not take
the combination of estrogen and progestin in an effort
to prevent age-associated memory loss. And, with this
additional evidence, it appears this therapy could be
more harmful than helpful to postmenopausal women."
Women
in the estrogen plus progestin part of the WHI trial
stopped taking their study pills in July after research
results indicated that for those on the combined
therapy, the overall risks (breast cancer, heart
attacks, stroke and blood clots) outweighed the benefits
(fewer fractures and colorectal cancers).
Memory
study participants' cognitive function was tested at the
start of the study and then annually with a standard
mental state examination. Cognitive measures also were
determined by friends or family members who could
provide information about the participants' cognitive
and behavioral function.
WHIMS
researchers' intent was to determine whether estrogen --
either alone or combined with progestin -- could reduce
the risk of dementia and mild cognitive impairment in
healthy women who are 65 and older.
Dementia involves progressive impairment of all aspects
of brain function and is characterized by changes in
memory, personality and behavior, and difficulty in
carrying out normal daily activities. Mild cognitive
impairment refers to a specific type of memory loss, in
which people have sharp thinking and reasoning skills,
but a decline in their short-term memory.
SOURCE: Journal
of the American Medical Association, May 28, 2003
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