Menopause Resource Center
Facts
About Postmenopausal Hormone Therapy
article syndicated from NHLBI
NOTE:
Since this fact sheet was written in October 2002,
a development has occurred that may affect
your health decisions. The National Institutes of Health
stopped the estrogen-alone
study of the Women's Health Initiative (WHI).
Choosing whether or not to use postmenopausal hormone
therapy can be one of the most important health decisions
women face as they age. As with taking any treatment,
the decision involves carefully weighing the risks
and benefits involved.
But, until recently, the picture of those risks and
benefits has been unclear. Studies gave conflicting
results about the therapy's effects on breast cancer,
heart disease, and other conditions.
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Box 1
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Oral Estrogen and Estrogen/Progestin Products*
|
|
Estrogen pills:
|
|
Premarin
|
conjugated equine estrogens
|
|
Cenestin
|
synthetic conjugated estrogens
|
|
Estratab
|
esterified estrogens
|
|
Menest
|
esterified estrogens
|
|
Ortho-Est
|
estropipate (piperazine estrone
sulfate)
|
|
Ogen
|
estropipate (piperazine estrone
sulfate)
|
|
Estrace
|
micronized 17-beta-estradiol
|
|
Progestin pills:
|
|
Amen
|
medroxyprogesterone acetate
|
|
Cycrin
|
medroxyprogesterone acetate
|
|
Provera
|
medroxyprogesterone acetate
|
|
Micronor
|
norethindrone
|
|
Nor-QD
|
norethindrone
|
|
Aygestin
|
norethindrone acetate
|
|
Ovrette
|
norgestrel
|
|
Norplant
|
levonorgestrel
|
|
Prometrium
|
progesterone USP (in peanut
oil)
|
|
Megace
|
megestrol acetate (not for uterine
protection)
|
|
Estrogen plus progestin pills:
|
|
Premphase
|
conjugated equine estrogens
and medroxyprogesterone acetate
|
|
Prempro
|
conjugated equine estrogens
and medroxyprogesterone acetate
|
|
Femhrt
|
ethinylestradiol and norethindrone
acetate
|
|
Activella
|
17-beta-estradiol and norethindrone
ecetate
|
|
Ortho-Prefest
|
17-beta-estradiol and norgestimate
|
|
* As of Fall 2000
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Back to Top
In the summer of 2002, new findings emerged that have
finally begun to fill in some of the picture's details.
While much more remains to be learned, the findings
offer women some guidance about the risks and benefits
of using postmenopausal hormone therapy.
This fact sheet discusses those findings and gives
you an overview of such topics as menopause, hormone
therapy, and alternative treatments to the symptoms
of menopause and various health risks that come in
its wake. It also provides a list of sources you can
contact for more information.
If
you're on hormone therapywhether short- or
long-term useyou're bound to have a lot of concerns.
This fact sheet will provide some information, but
it's important to talk with your doctor or other health
care provider about your health profile. Being informed
is one of the best ways you can protect your health.
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Box 2
|
Gels, Creams, Patches, and Other Hormone
Products*
|
|
Estrogen products:
|
|
Cream
|
Estrace
|
micronized 17-beta-estradiol
|
| |
Ortho Dienestrol
|
dienestrol
|
| |
Premarin
|
conjugated equine estrogens
|
|
Vaginal Tablet
|
Vagifem
|
estradiol hemihydrate
|
|
Vaginal Ring
|
Estring
|
micronized 17-beta-estradiol
|
|
Skin Patch
|
Alora
|
micronized 17-beta-estradiol
|
| |
Climara
|
micronized 17-beta-estradiol
|
| |
Esclim
|
micronized 17-beta-estradiol
|
| |
Estraderm
|
micronized 17-beta-estradiol
|
| |
Vivelle
|
micronized 17-beta-estradiol
|
| |
Vivelle-Dot
|
micronized 17-beta-estradiol
|
|
Progestin products:
|
|
Vaginal Gel
|
Crinone
|
progesterone
|
|
Injection
|
Depo-Provera
|
medroxyprogesterone acetate
(not for uterine protection)
|
|
IUD
|
Mirena
|
levonorgestrel
|
| |
Progestasert
|
progesterone
|
|
Estrogen plus progestin products:
|
|
Skin Patch
|
Combipatch
|
17-beta-estradiol and norethindrone
acetate
|
|
Ortho-Prefest
|
17-beta-estradiol and norgestimate
|
|
Injection
|
Depo-Testadiol
|
testosterone and estradiol cypionate
|
|
* As of Fall 2000
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Back to Top
Menopause and Hormone Therapy
As you age, significant internal changes take place
that affect your production of the two female hormones,
estrogen and progesterone. The hormones, which are
important in regulating the menstrual cycle and having
a successful pregnancy, are produced by the ovaries,
two small, oval-shaped organs.
During the years just before menopause, known as perimenopause,
your ovaries begin to shrink. Levels of estrogen and
progesterone fluctuate as your ovaries try to keep
up production of the hormones. You can have irregular
menstrual cycles, along with unpredictable episodes
of heavy bleeding during a period. Perimenopause usually
lasts several years.
Eventually, your periods stop. Menopause marks the
time of your last menstrual period. It is not considered
the last until you have been period-free for 1 year
without being ill, pregnant, breast-feeding, or using
certain medicines, all of which also can cause menstrual
cycles to cease. There should be no bleeding, even
spotting, during that year. Natural menopause usually
happens sometime between the ages of 45 and 54.
You also can undergo menopause as the result of surgery.
A surgical procedure, called a hysterectomy, removes
the uterus and sometimes the ovaries and fallopian
tubes as well. You go through menopause if both of
your ovaries are removed. Otherwise, the surgery does
not affect menopause, which still occurs naturally.
Whether
you go through menopause naturally or surgically,
symptoms can result
as your body tries to adjust to
the drop in estrogen levels. These symptoms vary greatlyone
woman may breeze through menopause with few symptoms,
while another has difficulty. Symptoms may last for
several months or years, or persist. The most common
symptoms are hot flashes or flushes, sweats, and sleep
disturbances. (A hot flash is a feeling of heat in
your face and upper body, which may cause the skin
to appear flushed or red as blood vessels expand. Hot
flashes that occur with severe sweating during sleep
are called night sweats.) But the drop in estrogen
also can contribute to other symptoms, such as changes
in the vaginal and urinary tracts, which can cause
painful intercourse, urinary infections, and the need
to urinate more often.
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Box 3
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Hormone Therapy Schedules
- Cyclic
or sequentialEstrogen
for 25 or 30 days a month, with progestin
added for
10-14 days
- Continuous-combinedEstrogen
and progestin daily
|
To relieve the symptoms of menopause, doctors may
prescribe postmenopausal hormone therapy. This can
involve the use of either estrogen alone or with another
hormone called progesterone, or progestin in its synthetic
form. The two hormones normally help to regulate a
woman's menstrual cycle. Progestin is added to estrogen
to prevent the overgrowth (or hyperplasia) of cells
in the lining of the uterus. This overgrowth can lead
to uterine cancer. If you haven't had a hysterectomy,
you'll receive estrogen plus progestin therapy; if
you have had a hysterectomy, you'll receive estrogen-only
therapy. Hormones may be taken daily (continuous use)
or on only certain days of the month (cyclic use).
They also can be taken in several ways, including
orally, through a patch on the skin, as a cream or
gel, or with an intrauterine device (IUD) or vaginal
ring. How the therapy is taken can depend on its purpose.
For instance, a vaginal estrogen ring or cream can
ease vaginal dryness, urinary leakage, or vaginal or
urinary infections, but does not relieve hot flashes.
Hormone therapy may cause side effects, such as bleeding,
bloating, breast tenderness or enlargement, headaches,
mood changes, and nausea. Further, side effects vary
by how the hormone is taken. For instance, a patch
may cause irritation at the site where it's applied.
Box 1, Box 2,
and Box 3 list products and schedules
for various hormone therapies. There also are nonhormonal
approaches to easing the symptoms of menopause. Box
4 offers a list of some of these alternatives.
Back to Top
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Box 4
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Alternatives to Hormone Therapy to Help
Prevent Postmenopausal Conditions and Relieve
Menopausal Symptoms
You may want to consider alternatives
to hormone therapy to ease menopausal symptoms.
The list below includes some locally applied
hormone products (which may not carry the same
risks as those that deliver medication throughout
the body), dietary supplements, and lifestyle
measures. Talk with your doctor or other health
care provider about the best treatment for you
for each symptom.
Be aware that, unlike drugs,
the U.S. Food and Drug Administration (FDA) does
not have the authority to approve dietary supplements
before they are sold. The dietary supplement
manufacturer is responsible for insuring that
the product is safe and that any representations
or claims made about it are adequately substantiated
and not false or misleading (see
Box 5).
One
positive move you can make to feel better
is to
adopt a healthy lifestyledon't
smoke, eat a variety of foods low in saturated
fat and cholesterol and moderate in total
fat, maintain a healthy weight, and be
physically
active.
For postmenopausal conditions:
Osteoporosis
- See Box 20 for lifestyle
behaviors to protect bone density
- Designer estrogen Raloxifene (Evista), which
preserves bone density
- Bisphosphonates Actonel or Fosamax, which
reverse bone loss and prevent fractures
- Calcitonin (a nasal spray), which may prevent
fractures
- Note:
Phytoestrogens (see "Hot flashes" below)
have not been shown to reduce fractures
Heart disease
- Lifestyle behaviors, including:
- Following a healthy eating plan
- Limiting consumption of alcoholic beverages
- Not smoking
- Maintaining a healthy weight
- Being physically active
- Preventing and controlling high blood pressure
- Preventing and controlling high blood cholesterol
- Managing diabetes
- Taking prescribed medication to control
heart disease
For menopausal symptoms:
Hot flashes
- Lifestyle changes. These include
dressing and eating to avoid being too warm,
sleeping in a cool room, and reducing stress.
Avoid spicy foods and caffeine. Try deep breathing
and stress reduction techniques, including
meditation and other relaxation methods.
- Soy. This
contains phytoestrogens. (Phytoestrogens
are estrogen-like
substances
derived from a plant source.) However,
there is no solid evidence that soyor other
sources of phytoestrogensreally do
relieve hot flashes. Further, the risks
of taking soy,
especially the more concentrated forms
of soy, such as pills and powders, are
not known. Phytoestrogens
from soy can be consumed through foods
or supplements. Soy food products include
tofu, tempeh, soy
milk, and soy nuts. These soy products
are more likely to work on mild hot flashes.
- Other sources of phytoestrogens. These
include such herbs as black cohosh, a member
of the buttercup family, wild yam, dong quai,
and valerian root.
- Antidepressants, such as Effexor,
Paxil, and Prozac have been proved moderately
effective in clinical trials; however, they
have not been approved for this use.
Vaginal dryness
- Vaginal lubricants and moisturizers (available
over the counter).
- Products
that release estrogen locally (such as
vaginal creams,
a vaginal suppository, called
Vagifem, and a plastic ring, called an
Estring)these
are used for more severe dryness. The ring
contains a low dose of estrogen and may
not protect against osteoporosis. It
also must
be changed every 3 months.
Mood swings
- Lifestyle behaviors, including getting enough
sleep and being physically active
- Relaxation exercises
- Antidepressant or anti-anxiety drugs
Insomnia
- Over-the-counter sleep aids
- Milk
products, such as a glass of milk or
cup of yogurtchoose
low- or fat-free varieties
- Do
physical activity in the morning or early
afternoon exercising
later in the day may increase wakefulness
- Hot shower or bath immediately before going
to bed
Memory problems
- Mental exercises
- Lifestyle behaviors, especially getting enough
sleep and being physically active
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Back to Top
Postmenopausal Use
Menopause may cause other changes that produce no
symptoms yet affect your health. For instance, a woman's
risk of developing heart disease begins to rise around
menopause. After menopause, women's rate of bone loss
increases. The increased rate can lead to osteoporosis,
which may in turn increase the risk of bone fractures,
usually after age 70.
Through
the years, studies were finding evidence that estrogen
might
help with some of these postmenopausal
health risks especially heart disease and osteoporosis.
With more than 40 million American women over age 50,
the promise seemed great.
Although
erroneously thought of in the past as a "man's
disease," heart disease is the leading killer of American
women. Women typically develop it about 10 years later
than men.
Similarly, menopause is a time of increased bone loss.
Bone is living tissue. Old bone is continuously being
broken down and new bone formed in its place. With
menopause, bone loss is greater and, if not enough
new bone is made, the result can be weakened bones
and osteoporosis, which increases the risk of breaks.
One of every two women over age 50 will have an osteoporosis-related
fracture during her life.
Many scientists believed these increased health risks
were linked to the postmenopausal drop in estrogen
produced by the ovaries and that replacing estrogen
would help protect against the diseases.
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Box 5
|
About Dietary Supplements
If
you use dietary supplements to try to ease
hot flashes
and other menopausal symptoms, you should
bear these points in mind: The U.S. Food
and Drug
Administration (FDA) does not have the authority
to approve dietary supplements before they
are marketed, and it's important to tell
your health
care provider that you are taking such remedies.
Dietary supplements are sold
over the counter and may contain phytoestrogens:
These are estrogen-like substances that come
from some plants (such as soy) and plant materials
(such as legumes, vegetables, cereals, and some
herbs). For instance, these products may contain
black cohosh, wild yams, dong quai, and valerian
root.
Dietary supplement manufacturers
are responsible for making sure that their products
are safe. The FDA must show that a dietary supplement
is harmful before it can limit the product's
use or remove it from the market. Currently,
there are no FDA regulations that specifically
establish minimum standards for the manufacture
of dietary supplements in order to insure their
identity (tests to insure that the ingredient
is actually what its label claims), purity, quality,
strength, and composition. You may want to contact
a product's manufacturer before buying it.
Furthermore, the possible effects
of the products are not known. Some of the substances
they contain are being studied. For example,
soy contains plant estrogens, which are being
studied to see if they have the same risks and
benefits as estrogen.
Some of this research is being
supported by the Office of Dietary Supplements,
the National Center for Complementary and Alternative
Medicine, the National Institute on Aging, and
other units of the National Institutes of Health.
Until more is known about these
substances, you should use them with caution.
Also, as noted, tell your health care provider
if you take a dietary supplement or if you increase
your intake of dietary phytoestrogens. There
may be dangerous side effects. An increase in
the level of estrogens in your body could interfere
with other prescription medications you are taking
or even cause an overdose.
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Back to Top
Early Findings
Early studies seemed to support hormone therapy's
ability to protect women against the diseases that
tend to occur after menopause. For instance, research
showed that the treatment does prevent osteoporosis.
However, other findings lacked evidence or were unclear.
No large clinical trials had proved that hormone therapy
prevents heart disease or fractures. Answers also were
needed about other possible effects of long-term use
of hormones, especially on such conditions as breast
and colorectal cancers.
Further, prior research on postmenopausal hormone
therapy's effect on heart disease had involved mainly
observational studies, which can indicate possible
relationships between behaviors or treatments and disease,
but cannot establish a cause-and-effect tie. (See
Box 6 for more about types of studies.)
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Box 6
|
What We Lean From Different Types of Studies
Medical researchers conduct
many types of studies. The reason is that the
studies yield different kinds of information.
Together, the studies help scientists understand
health and disease, and how to educate people
so they can lead healthier lives.
Three main types are: observational
studies, clinical trials, and community prevention
studies. Each type is discussed briefly below:
Observational
studies follow women's medical and lifestyle
practices but do not intervene. Such studies
can turn up possible relationships between
various factors and health or illness. Those
factors include population traits, ethnicity,
genetic attributes, and behaviors. For instance,
researchers can track women who do and do not
take postmenopausal hormone therapy. The results
may show that the hormone users have fewer
heart attacks. But the results cannot conclude
that hormone therapy reduces the risk of heart
disease. Other factors may have played a part.
For instance, compared with women who do not
use hormone therapy, those who do are often
healthier, have a higher level of education
and better access to medical care, and are
more willing to follow a prescribed therapy.
Clinical trials control
and compare specific medical interventions, such
as the use of postmenopausal hormone therapy.
Women on an intervention are compared with those
who do not receive the treatment. Researchers
try to control all of the experimental conditions
so that any difference between the two groups
can be tied to the intervention.
The
most rigorous of these investigations is
the
randomized, controlled, double-blinded
clinical trial. Women are randomly assigned
to the study groups and, in a drug trial
for instance,
neither the women nor the researchers typically
know who is receiving an active drug and
who a placebo. Further, on average women
in the two
groups will be similar in age, education,
health at the time of entering the trial,
and other
factors that may affect the results. These
trials are considered to be the "gold standard" among
types of studies because they yield the most
reliable information. Clinical trials are
often done to test whether a possible relationship
uncovered in an observational study is in
fact
so. The trials help establish a causal link
between a treatment and a specific medical
outcome, such
as fewer heart attacks.
Community prevention studies explore
ways to encourage people to adopt healthier behaviors.
|
There
also were some clinical trials, which are considered
the "gold standard" in establishing a cause-and-effect
connection between a behavior or treatment and a disease.
The most definitive clinical trials are those that
test the effects of a treatment on the disease itself.
But such clinical trials are time-consuming and costly.
Consequently, early clinical trials of postmenopausal
hormone use tested the therapy's effects on the risk
factors or predictors of various diseases. One of the
most important of these early clinical trials that
tested effects on risk factors was the "Postmenopausal
Estrogen/ Progestin Interventions Trial," or PEPI.
Supported by the National Heart, Lung, and Blood Institute
(NHLBI) and other units of the National Institutes
of Health (NIH), PEPI tested the effects of four hormone
regimens (one estrogenonly and three different
estrogen plus progestin regimens) on key risk factors
for heart disease and bone mass. Begun in 1987, it
followed 875 healthy, postmenopausal women, ages 45-64,
for 3 years. About a third of the women had had a hysterectomy.
Participants included various races but were predominantly
white.
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Box 7
|
Risk Factors for Uterine Cancer
There are various types of uterine
cancer. The most common is endometrial cancer,
which begins in the lining (endometrium) of the
uterus. It is often referred to as uterine cancer.
Key risk factors for uterine
cancer are:
- Ageusually
occurs after age 50
- Endometrial
hyperplasiaan
increase in cells in the lining of the
uterus
- Hormone
therapyusing
estrogen without progesterone
- Obesity and related conditions
- Tamoxifentaken
to prevent breast cancer
- Racewhite
women are more likely than African American
women to develop uterine cancer
- Colorectal
cancerthose
who have an inherited form are at a higher
risk of developing
uterine cancer
- Factors
that increase exposure to estrogennot
having children, starting menstruation
at an early age, entering menopause late
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Back to Top
PEPI's results were generally positive:
-
Each
of the hormone regimens reduced "bad" LDL
cholesterol and raised "good" HDL cholesterol,
although estrogen-only raised good cholesterol
the most. (LDL,
or low density lipoprotein, carries cholesterol
to tissues, including the arteries, while HDL,
or high
density lipoprotein, carries it away, aiding
its removal from the body.)
-
All hormone therapies decreased levels of fibrinogen.
(High levels of fibrinogen allow blood clots to form
more readily, thus increasing the risk of heart disease
and stroke.)
-
On the other hand, a large percentage of those
who took estrogen alone had a high rate of overgrowth
of the uterine lining and other abnormalities. This
finding stressed the need for women with a uterus
to use estrogen plus progestin therapy. The added
progestin protects women against uterine cancer (see
Box 7).
|
Box 8
|
Breast Cancer Risk Factors
About 80 percent of breast cancer
cases occur after age 50. One of every eight
American women who live to be 85 develops breast
cancer. Some factors increase the risk for breast
cancer. However, most women who develop breast
cancer do not have any of the risk factors.
Key factors that increase
the risk of developing breast cancer are:
- Personal
historyif
you've had it once, you're more likely
to develop it again
- Family
historyif
your mother, sister, or daughter had
breast cancer, especially at
an early age, you're more likely to develop
it
- Other
breast changes (not including ordinary "lumpiness")such
as atypical hyperplasia (an irregular pattern
of cell growth)
- Genetic
alterationschanges
in certain genes, including BRCA1 and
BRCA2 mutations
Other factors also may increase
the risk of developing breast cancer. These
include:
- Racewhite
women are more likely to develop it than
African
American or Asian women
- Estrogen
exposurerisk
is somewhat increased for those who began
menstruation
early (before age 12), had menopause late
(after age 55), never had children, or
took hormone
therapy for long periods
- Late
childbearinghaving
a first child after about age 30
- Radiation
therapyif
given to the chest more than 10 years
ago, especially in women
younger than age 30
- Breast
densitybreasts
with a high proportion of lobular and
ductal tissue, which
is dense and in which breast cancers usually
appear
- Alcoholic beverage consumption
|
PEPI did not last long enough to tackle some crucial
questions about hormone therapy, such as a possible
rise in breast cancer risk (see Box
8).
The
first clinical trial to investigate the effects of
postmenopausal
hormone therapy directly on diseases
was the "Heart and Estrogen-Progestin Replacement Study," or
HERS, which began enrolling participants in January
1983. HERS tested whether estrogen plus progestin would
prevent a second heart attack or other coronary event.
Altogether, it involved 2,763 postmenopausal women,
average age 67, who already had heart disease. The
women received either estrogen plus progestin or a
placebo for about 4 years. (A placebo is a substance
that looks like the real drug but has no biologic effect.)
Back to Top
|
Box 9
|
WHI Findings On Estrogen Plus Progestin
Therapy
Compared with a placebo, after
about 5 years of use, estrogen plus progestin
resulted in:
Increased risks
- 26% increase in breast cancer
- 41% increase in strokes
- 29% increase in heart attacks
- Doubled rates of blood clots in legs and
lungs
Increased benefits
- 37% less colorectal cancer
- 34% fewer hip fractures
No difference
|
|
Box 10 [skip to text version]
|
Estrogen Plus Progestin Pills vs. Placebo
Pills
The rate of the following medical
conditions per 10,000 women per year

|
|
Box
10 Text Version [skip to graphical
version]
|
Estrogen Plus Progestin Pills vs. Placebo
Pills
The rate of the following medical
conditions per 10,000 women per year
| |
Placebo Pills
|
Estrogen Plus
Progestin Pills
|
|
Breast Cancer
|
30
|
38
|
|
Heart Attack
|
30
|
37
|
|
Stroke
|
21
|
29
|
|
Total Blood Clots
|
16
|
34
|
|
Hip Fracture
|
15
|
10
|
|
Colorectal Cancer
|
16
|
10
|
|
Findings, released in 1998, showed that those on the
hormone therapy did not have fewer fatal or nonfatal
heart attacks. In fact, the women's risk for a heart
attack increased during the first year of hormone use,
declining thereafter. HERS also showed that the therapy
caused an increase in blood clots in the legs and lungs.
More
recently, the "HERS Follow-Up Study," which
tracked the women for about 3 more years, found no
decrease
in heart disease from use of estrogen plus progestin
therapy.
Back to Top
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Box 11
|
What Do the Data Really Mean?
The
data sound scaryand
confusing. A 41 percent increase in strokes.
A 34 percent decline in hip fractures. Which
is more important? The bad news, or the good?
Either
way, the percentages sound big. So it's good
to take a moment and check out what they're really
saying.
There
are two main ways to express risk"relative risk" and "absolute risk." The
relative risk measures and compares the percent
change in risk of some health-related event
in a population that has been exposed to
some agent
and another that has not. The increase (or
decrease) in absolute risk is an estimate
of the number
or proportion of women who will (or will
not) develop a disease when exposed to
a particular
agent.
Relative
risk allows scientists to compare data.
In the WHI study, for example,
scientists wanted to find out the relative
risk of breast cancer in women who had
and had not
been exposed to the estrogen plus progestin
hormone therapy. After about 5 years, the
study had 166
cases of breast cancer among estrogen plus
progestin users, compared with 124 in the
placebo group.
However, there were more woman in the hormone
group8,506, compared with 8,102 in
the placebo group. To be able to compare
data from
the groups, the cases were converted into
rates per 10,000 women per year. Thus, the
rate of
breast cancer in the hormone group was 38
per 10,000 women, compared with 30 per 10,000
women
in the placebo group. This also can be expressed
as 38 divided by 30 or 1.26. Since that is
0.26 greater than an equal risk (or 1.00),
the women
on hormone therapy had a 26 percent greater
chance of developing breast cancer than non-users.
What was the increase in absolute
risk of developing breast cancer for women in
the WHI study? On average, in any single year,
0.08 percent more women in the hormone group
developed breast cancer than women in the placebo
group. This means that, if a group of 10,000
women takes estrogen plus progestin for a year,
there will be 8 more cases of breast cancer among
the hormone users than if they hadn't taken the
therapy. Thus, women on the hormone therapy have
only a slightly increased absolute risk of breast
cancer over a year. (See Boxes 9 and 10 for
a summary of the relative and absolute risks
of breast cancer and other conditions for women
in the estrogen plus progestin study.)
But,
if you count up all the added cases of
breast
cancer, heart attacks,
strokes, and blood clots in the lungs and
subtract the fewer cases of colorectal
cancer and hip
fractures, you'd still get about 100 extra
harmful events among the 10,000 hormone
users after 5.2
yearsthe period the study ran. Multiply
that by 10 years and millions of women and
the number of cases of adverse effects grows.
Remember too that reports of
increased risks do not mean you will develop
breast cancer or another condition if you have
been using the hormone therapy. Your personal
and family medical history, along with your lifestyle
and other influences, play a big role in your
chance of developing a disease.
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The Women's Health Initiative
In
1991, the NHLBI and other units of the NIH launched
the "Women's Health Initiative" (WHI),
one of the largest studies of its kind ever undertaken
in the United States.
It consists of a set of clinical trials, an observational
study, and a community prevention study, which altogether
involve more than 161,000 healthy, postmenopausal women.
The observational study is looking for predictors
and biological markers for disease and is being conducted
at more than 40 centers across the United States, while
the community prevention study, which has ended, sought
to find ways to get women to adopt healthful behaviors
and was done with the Federal Government's Centers
for Disease Control and Prevention.
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WHI's three clinical trials, conducted at the same
U.S. centers, are designed to test the effects of postmenopausal
hormone therapy, diet modification, and calcium and
vitamin D supplements on heart disease, osteoporotic
fractures, and colorectal cancer risk.
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Box 12
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Risk Factors for Stroke
Main risk factors are:
- High blood pressure
- Diabetes
- Cigarette smoking
Other risk factors include:
- Family
historystroke
appears to run in some families, whether
due to genetics and/or
shared lifestyle
- Heavy consumption of alcoholic beverages
- High blood cholesterol
- Menopause
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The postmenopausal hormone therapy clinical trial
has two parts. The first involved 16,608 postmenopausal
women with a uterus who took either estrogen plus progestin
therapy or a placebo. The second involves 10,739 women
who have had a hysterectomy and are taking estrogen
alone or a placebo.
The estrogen plus progestin trial used 0.625 milligrams
of conjugated equine estrogens taken daily plus 2.5
milligrams of medroxyprogesterone acetate taken daily
(Prempro). Two key reasons that that combination was
chosen are: It is the mostly commonly prescribed form
of the combined hormone therapy in the United States,
and, in several observational studies, it had appeared
to benefit women's health.
The women in the WHI estrogen plus progestin study
were aged 50 to 79. They enrolled in the study between
1993 and 1998. Their health was carefully monitored
by an independent panel, called the Data and Safety
Monitoring Board (DSMB).
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Box 13
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Risk Factors for Colorectal Cancer
About
30,000 women a year die of colorectal cancerit
is the third-leading cause of cancer deaths
for women, after lung
and breast cancers.
Factors that increase the risk of colorectal
cancer include:
- Agerisk
increases after age 50
- Dieteating
a diet high in fat and calories, and
low in
fiber
- Polypsthese
are benign growths on the inner wall
of the
colon and rectum
- Personal
medical historyhaving
had cancer of the ovary, uterus, or breast;
also
having had colorectal cancer once increases
the chance of developing it again
- Family
medical historyhaving
first-degree relatives (parents, siblings,
or children)
with colorectal cancer, especially at a
young age; risk increases even more if
many family
members have had colorectal cancer
- Ulcerative
colitisa
condition in which the lining of the
colon becomes inflamed
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The study's main goal was to see if the therapy would
help prevent heart disease and hip fractures. Another
goal was to see if those possible benefits were greater
than the possible risks from breast cancer, endometrial
(or uterine) cancer, and blood clots.
The
study was to have continued until 2005. However,
it was stopped in
July 2002 because the DSMB found
an increased risk of breast cancer and that, overall,
risks from use of the hormones outweighed and outnumbered
the benefits. "Outnumbered" means that more women had
adverse effects from the therapy than benefitted from
it. The key results are shown in Boxes 9 and 10.
These results show both risks and benefits from use
of the estrogen plus progestin therapy. The key adverse
effects were more cases of breast cancer, heart attacks,
strokes, and blood clots. The main benefits were fewer
hip and other fractures and cases of colorectal cancer.
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Box 14
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Postmenopausal Hormone Therapy and Ovarian
Cancer Risk
Early studies of postmenopausal
hormone therapy found inconsistent results about
its effect on the risk of ovarian cancer: Some
reported increased risk with estrogen use, while
others reported no effect or even a protective
one. Most of those studies were relatively small
and did not take into account the key risk factors
for ovarian cancer (see Box
15).
More recently, two large observational
studies have indicated that long-term estrogen
use increases the risk of ovarian cancer. It's
important to keep in mind that observational
studies do not prove that a treatment causes
a disease (see Box 6). The
evidence from these studies is cautionary, not
definitive.
Here's more on the studies:
- One
study followed 211,581 postmenopausal
women from 1982-1996.
Of those, 44,260 had
used estrogen-only hormone therapy; the
rest did not use hormone therapy. None
of the women
had had a hysterectomy, ovarian surgery,
or cancer. Those with 10 or more years
of estrogen
use had an increased risk of dying from
ovarian cancerand, while the risk
decreased somewhat long after use was
stopped, it was still higher
than that of women who had never used estrogen-only
therapy.
- Another study followed 44,241 women from
1979-1998. It found that estrogen-only therapy
increased the risk of ovarian cancer. Women
who used estrogen alone for 10 or more years
had an 80 percent higher risk of ovarian cancer
than women who had never used the hormone therapy;
women who used estrogen alone for 20 or more
years had a 220 percent higher risk than women
who had never used hormone therapy.
The study found no increased risk
of ovarian cancer for users of estrogen plus progestin. However,
few women in the study had used the combination therapy for
more than 4 years.
More
research is needed to see if estrogen plus
progestin
affects ovarian cancer
riskand on other aspects of postmenopausal
hormone use. For instance, another recent
study found that estrogen alone or estrogen
plus progestin
used on a sequential basis increased the
risk for ovarian cancer, while estrogen plus
progestin
used continuously did not.
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Additionally,
there was no increase in deaths from breast cancer
or from
other causes. Further, there
was no increase in the risk of endometrial cancer.
Here's more on the findingsto better understand
them, see "Putting It All Together," as
well as Box 11:
-
Breast cancer. The
increased risk of breast cancer appeared
after 4 years
of hormone
use. After
5.2 years, estrogen plus progestin resulted
in a 26 percent increase in the risk of breast
canceror
8 more breast cancers each year for every
10,000 women. Women who had used estrogen plus
progestin
before entering the study were more li |