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 Many women have been reluctant to use HRT to ease menopause symptoms
since 2002, when the federally funded Women’s Health Initiative (WHI)
study linked the treatments containing man-made versions of the
female hormones estrogen and progesterone to an increased risk of
breast cancer, heart attacks and strokes.
For the current study, researchers found that overall, estrogen-only
therapy carries a lower risk of blood clots than treatment with a
combination of estrogen and progestin, the synthetic version of
progesterone.
But there wasn’t a significantly higher clot risk with combination
therapy if women got estrogen from patches that deliver medicine
through the skin into the bloodstream or from vaginal estrogen
creams.
This suggests that estrogen pills may be a bigger problem than
alternative formulations, said Dr. JoAnn Pinkerton, executive
director of the North American Menopause Society and a researcher at
the University of Virginia in Charlottesville.
The risk of having a blood clot may be influenced by the type of
estrogen and whether some form of progesterone is added, and if so,
what type, Pinkerton, who wasn’t involved in the study, said by
email.
Women go through menopause when they stop menstruating, which
typically happens between ages 45 and 55. As the ovaries curb
production of estrogen and progesterone in the years leading up to
menopause, women can experience symptoms ranging from irregular
periods and vaginal dryness to mood swings and insomnia.
The Swedish study led by Dr. Annica Bergendal of the Karolinska
Institute in Stockholm analyzed data on 838 women who developed
blood clots from 2003 to 2009 and a control group of 891 similar
women who didn’t develop clots.
Women who took combined estrogen and progestin therapy had nearly
triple the clot risk of women who didn’t use hormones at all,
researchers report in the journal Menopause.
When women only used estrogen, their clot risk was 31 percent higher
than taking no hormones, though there wasn’t any greater risk
associated with estrogen delivered vaginally or through the skin.
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The study is observational, and can’t prove vaginal estrogen or skin
patches cause fewer blood clots than alternative treatments, the
authors note. Researchers also lacked data to verify the exact
timing of menopause, which can influence the blood clot risk
associated with HRT.
It’s also possible that these results don’t directly contradict the
WHI findings because of differences between the women in the U.S.
and Swedish studies, said Dr. Michael Thomas, a women’s health
researcher at the University of Cincinnati Academic Health Center
who wasn’t involved in the study.
Women in the current study were 55 years old on average, while WHI
participants were typically around 63.
Age differences between the Swedish and U.S. groups might explain
differences in the clot risks found, Thomas said by email. It’s also
possible women in the U.S. study might have been more prone to
obesity or other risk factors for clots that set them apart from
their Swedish counterparts.
SOURCE: http://bit.ly/1SpqaEt Menopause, online March 18, 2016.
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