Hormone
therapy heart benefit may depend on timing
(This article was first printed in the April
2006 issue of the Harvard Women's Health
Watch. For more information or to order,
please go to www.health.harvard.edu/womens.)
A study suggests that hormone therapy may be
good for the heart after all — but only
if it’s initiated during a fairly narrow
window of opportunity. Researchers at the Harvard
Medical School analyzed data from the Nurses’ Health
Study, which has followed more than 120,000 female
nurses since 1976. They found that women who
started hormone therapy within about four years
of menopause had a risk for heart disease nearly
30% lower than that of women who never used hormones.
On the other hand, beginning hormone therapy
10 or more years after menopause or after age
60 showed little if any benefit. The findings
were published in the January/February 2006 issue
of the Journal of Women’s Health.
The Harvard study, co-authored by Dr. JoAnn
Manson, was undertaken to shed light on apparent
discrepancies between earlier studies linking
postmenopausal hormones with a reduced risk for
heart disease and results from the Women’s
Health Initiative (WHI), which tested both an
estrogen and progestin combination (Prempro)
and estrogen alone (Premarin) against a placebo.
The Prempro trial was halted in 2002 when it
became clear that hormone users were experiencing more heart
disease, stroke, and blood clots than the women
taking the placebo pill. The estrogen-only trial
also ended early, in 2004, because Premarin increased
participants’ risk for stroke without conferring
any benefits for heart health.
These unanticipated findings led to considerable
confusion and a sea change in clinical practice.
Once widely prescribed long-term because it was
thought to stave off heart problems and other
age-related illnesses, hormone therapy was quickly
relegated to strictly short-term treatment of
symptoms such as hot flashes and vaginal dryness.
Several questions arose in the wake of the WHI’s
landmark effort to ascertain hormone therapy’s
role in disease prevention. A chief criticism
was that the WHI tested hormone therapy in women
who were mostly in their 60s and 70s, whose arteries
may already have had the beginnings of heart
disease (atherosclerosis). However, outside of
studies, women usually begin taking hormone therapy
in their late 40s or early 50s to treat menopausal
symptoms. WHI participants who were younger at
the start of the study may have fared better.
Analysis of the data continues, and we should
know more about that soon.
In the meantime, the findings from the Nurses’ Health
Study suggest that starting hormone therapy earlier
may indeed make a difference. But Dr. Manson
and her colleagues emphasize that many questions
remain, especially about the safety of long-term
hormone use in younger women: “More research
is needed to confirm this apparent association
and to improve our understanding of the benefits
and risks of hormone therapy when started early
after menopause,” says Dr. Manson. “Fortunately,” adds
gynecologist Dr. Martha K. Richardson, “there
are many other drugs and lifestyle options for
preventing heart disease in women.”
Studies are already under way to find out more
about hormone therapy. The Kronos Early Estrogen
Prevention Study (KEEPS) is testing whether starting
hormone therapy six months to three years after
the last menstrual period will prevent the progression
of atherosclerosis. The trial will also test
two different types of hormone preparations at
low doses. Dr. Manson is a principal investigator
with KEEPS. Another study, the Early versus Late
Intervention Trial with Estradiol (ELITE), funded
by the National Institutes of Health, will compare
the effects of estrogen (estradiol) started in
early menopause with estrogen begun 10 or more
years after menopause.
(This article was first printed in the April
2006 issue of the Harvard Women's Health
Watch. For more information or to order,
please go to www.health.harvard.edu/womens.)
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