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A recent study published in the October issue of Natural Medicine
confirms several previous studies that suggest women who use
estrogen replacement
therapy after
menopause are at a lower risk of osteoporosis than post-menopausal women who do not take estrogen. The
researchers conducted a study with mice, revealing that the female hormone estrogen may
double or even triple the natural death of osteoclasts-cells responsible for destroying
bone. David Hughes, MD, of the University of Texas Health Science Center in San Antonio
said the study shows that estrogen may prevent excessive bone loss before and after
menopause by curtailing the life span of osteoclasts. Osteoporosis is a degenerative bone disease that mostly affects
post-menopausal women. It is estimated that one-third of women over age 50 have
osteoporosis. When a woman reaches menopause (typically around age 50), her body produces
less of the female hormone estrogen. Since estrogen helps maintain bone density , a
decrease in the hormone will result in some bone loss. Though most people believe bone is
a solid material, it is actually a living tissue that is continually destroyed by
osteoclasts and rebuilt by osteoblasts. If this destruction/reconstruction process is
unbalanced and bone loss is severe, women may experience symptoms
of osteoporosis (such as broken or fractured bones, back pain, or curved spine).
All cells, except cancer cells, have a natural process of
death (called apoptosis) to prevent uncontrolled growth. In addition to increasing the
rate of cell death, estrogen also appears to protect against osteoporosis by stimulating
osteoblasts-cells responsible for bone growth and repair. According to Dr. Hughes, the
osteoblasts are stimulated to increase their production of a cell-signaling molecule
called transforming growth factor beta-1 (TGF-b1). In another study, researchers found
that blocking TGF-b1 from cells significantly decreased the rate of cell death, making
women more prone to osteoporosis. Researchers also discovered that blocking TGF-b1 reduces
the effectiveness of tamoxifen-a drug used to treat or prevent breast cancer in
some women.
The development of a drug that mimics TGF-b1 to help
promote bone growth and repair may result in a new and effective approach to preventing
osteoporosis in post-menopausal women, said Dr. Hughes. Lawrence Raisz of the University
of Connecticut Health Center reminded women that Hughes’ study has not yet been
confirmed in humans. However, Dr. Raisz agrees that post-menopausal women do benefit from
taking estrogen.
In addition to preventing osteoporosis, estrogen replacement
therapy (also called hormone replacement therapy (HRT)) may
prevent heart disease , delay Alzheimer’s
disease , and improve insulin resistance in patients with Type II (adult
onset) diabetes. Possible negative
effects of estrogen replacement therapy include:
- bloating
- nausea
- breast tenderness (during the first three to four months of
treatment)
- vaginal bleeding
- fluid retention
- weight gain depression
- increased blood clotting
- migraine headaches
Although studies have been inconsistent, there appears to
be an emerging consensus that estrogen replacement therapy (HRT with estrogen alone) does not
significantly increase the risk for breast cancer. This appears to be true for women who
are on estrogen less than five years or who take less than 0.625 mg per day. After five
years of HRT, a woman’s risk of breast cancer does increase, although the degree of
risk is still uncertain. Click here for more
information about HRT and breast cancer
.
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resources and references
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