COLUMBUS, Ohio -- A study of women before and after surgically induced
menopause provides additional evidence that the hormone estrogen protects
them from heart disease.
Researchers studied women before and after surgery to remove their ovaries
-- a procedure that stops production of estrogen and immediately thrusts
women into "surgical menopause."
The results showed that within three months after surgery, study participants
had increased levels of total and LDL cholesterol (the so-called bad cholesterol),
and increases in blood pressure -- all heart disease risk factors. The
women also showed greater negative physiological responses to stress.
"This is convincing evidence that estrogen plays a vital role in determining
women's risk for heart disease," said Catherine Stoney, co-author of
the study and associate professor of psychology at Ohio State University.
The results also give additional support for the use of hormone replacement
therapy for post-menopausal women who have a
family or personal history of heart disease, she said.
Stoney conducted the study with Jane Owens and Karen Matthews of the University
of Pittsburgh and David Guznik of the University of Rochester. Their results
appear in the current (July 1997) issue of the journal Health Psychology.
Stoney said other studies have followed women through natural menopause
and also found increases in heart disease risk factors, including negative
responses to stress. But because menopause can take years, it was difficult
to say whether the results were due to the aging process or from the gradual
reduction in estrogen production by the ovaries. Few studies have examined
cardiovascular risk factors before and after surgical menopause, and none
have looked at stress responses.
"One of the things that was so striking to us with this study was
that the change in risk factors was nearly immediate -- within three months
of the surgery," she said.
The study involved women at the University of Pittsburgh Hospital, 10 who
underwent hysterectomies and removal of their ovaries (resulting in surgical
menopause) and 19 women who underwent hysterectomies only. All of the women
were within 30 percent of their ideal body weight and none used hormone
replacement therapy during the course of the study.
About 10 days before surgery, the women came to a laboratory where they
were given a series of written and physical tests designed to measure their
stress responses. Before and during these tests, the women were evaluated
on a variety of heart disease risk factors, including total and LDL cholesterol
levels, and blood pressure.
The same tests were given to the women three months after their surgery.
Before the surgery, both groups of women -- those who had their ovaries
removed and those who only had hysterectomies -- were similar in their heart
disease risk profiles.
After the surgery, the women whose ovaries were removed showed increases
in heart disease risk factors including higher cholesterol levels and higher
blood pressure. Their total cholesterol and LDL levels and blood pressure
also rose more sharply during the stressful tests they were given.
However, the women who had only undergone hysterectomies did not show similar
increases in their risk factors.
"The fact that women who only had hysterectomies didn't show changes
in their heart disease risk suggests that the ovary removal was the key
factor in increasing risk," Stoney said.
While the study was not designed to test the value of hormone replacement
therapy (HRT), Stoney said the results do shed some light on the issue.
HRT -- which provides post-menopausal women with the estrogen their body
no longer makes -- is considered controversial because of its alleged relation
to increased breast and ovarian cancer risk. But Stoney said this and many
other studies suggest that HRT should still be considered for women who
don't have a history of breast or ovary cancer in their families and who
do have a history of heart disease.
"Heart disease is a major, often overlooked problem in women,"
Stoney said. "Women with a family or personal history of heart disease
should be encouraged to consider HRT to protect their health."
Stoney's lab at Ohio State is currently looking at whether stress alters
metabolism of dietary fats. That may be one explanation of why cholesterol
levels increase during times of stress, she said. She is comparing differences
between men and women -- including pre-menopausal and post-menopausal women
-- in how their bodies react to stress.
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Contact: Catherine Stoney, (614) 292-0588; Stoney.1@osu.edu
Written by Jeff Grabmeier, (614) 292-8457; Grabmeier.1@osu.edu