News Story - Timing, Dosage of HRT Affect Chances of Heart Trouble
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By Amanda Gardner
HealthDay Reporter
Wed Oct 1, 11:46 PM ET
WEDNESDAY, Oct. 1 (HealthDay News) -- The largest observational study
of hormone replacement therapy since the landmark Women's Health
Initiative finds that how and when women take hormone replacement
therapy affects their heart attack risk.
Younger women had a higher risk of heart attacks, especially younger
women who took hormone replacement therapy (HRT) for a long time,
Danish researchers found. Certain formulations also lead to different
results.
"For women with an intact uterus, cyclic combined therapy (causing
menstrual bleedings) should be preferred instead of continuous
combined therapy (not causing menstrual bleedings)," said Dr. Ellen
Lokkegaard, lead author of the study published online Oct. 1 in the
European Heart Journal. "And for women without a uterus, dermal
application via gel or patch is associated with a lower risk."
"The regimen and route of administration should be considered
carefully when HRT is administered," concluded Lokkegaard, who is a
gynecologist at the Rigshospitalet in Copenhagen, Denmark.
A section of the U.S. government-sponsored Women's Health Initiative
(WHI), which was designed to look at health issues in postmenopausal
women, was halted in 2002, when U.S. researchers found that HRT led to
an increased risk of adverse events that included heart attack,
stroke, breast cancer and blood clots. The risk depended on whether
the woman was taking estrogen alone or estrogen plus progesterone,
another female hormone.
Since that time, however, a more complex picture has emerged with
various factors, including amount of hormone as well as timing of use,
determining the exact nature of risks and benefits.
Previous research indicated that HRT might have a negative effect on
cardiovascular health in women who started therapy long after
menopause, versus women taking it sooner after menopause.
Before the WHI, many women took HRT in the belief that it would reduce
their risk for heart disease.
These researchers looked at almost 700,000 healthy Danish women aged
51 to 69 who were followed for six years. There was no information on
whether the women were postmenopausal or not, although the authors
stated that most of even the younger women participating were probably
postmenopausal given the age range.
Overall, there was no increased risk of a heart attack in women who
were currently using HRT compared with women who had never used HRT.
There was, however, a 24 percent increased risk in younger women (aged
51 to 54) and a heightened risk in younger women taking the prescribed
medications for a longer period of time.
There was no correlation between long-term use of HRT in older women
and an elevated heart attack risk. Nor was there an increased risk
with estrogen alone.
A combination of estrogen and progesterone administered continuously
resulted in a 35 percent increased risk of heart attack compared with
women who had never used HRT. But estrogen taken alone, followed by
estrogen plus progesterone (a cyclical regimen) actually resulted in a
reduced risk of heart attack as compared to women who had never taken
HRT. The same reduced risk was also seen with the synthetic hormone
tibolone.
Estrogen taken via patch (on the skin) or gel (in the vagina) reduced
the risk of heart attack by 38 percent and 44 percent, respectively.
"Overall biological evidence suggests the findings are plausible,"
Lokkegaard said. "But the finding of significant lower risk among
women using vaginal estrogen was very surprising and needs to be
investigated further before clinical recommendations can be given."
The results were essentially similar to those from the Women's Health
Initiative.
However, one expert added a caveat.
"We have learned from observational data in the past that it is not an
appropriate scientific approach to draw conclusions about the benefits
or risks of hormone therapy in women," said Dr. Lori Mosca, director
of preventive cardiology at New York-Presbyterian Hospital/Columbia
University Medical Center and founder and director of the Columbia
Center for Heart Disease Prevention in New York City. "These data are
interesting, but in no way definitive," Mosca said.