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Osteoporosis
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What is Osteoporosis?
Osteoporosis is a
condition characterized by a decrease in the density of
bone, decreasing its strength and resulting in fragile
bones. Osteoporosis literally leads to abnormally porous
bone that is compressible, like a sponge. This disorder
of the skeleton weakens the bone and results in frequent
fractures (breaks) in the bones. Osteopenia is a
condition of bone that is slightly less dense than
normal bone but not to the degree of bone in
osteoporosis. |
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Normal bone is composed of protein,
collagen, and calcium, all of which give bone its
strength. Bones that are affected by osteoporosis can
break (fracture) with relatively minor injury that
normally would not cause a bone to fracture. The
fracture can be either in the form of cracking (as in a
hip fracture) or collapsing (as in a compression
fracture of the vertebrae of the spine). The spine,
hips, ribs, and wrists are common areas of bone
fractures from osteoporosis although
osteoporosis-related fractures can occur in almost any
skeletal bone. |
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What are
osteoporosis symptoms and signs? Osteoporosis
can be present without any symptoms for decades
because osteoporosis doesn't cause symptoms
until bone fractures. Moreover, some
osteoporotic fractures may escape detection for
years when they do not cause symptoms.
Therefore, patients may not be aware of their
osteoporosis until they suffer a painful
fracture. The symptom associated with
osteoporotic fractures usually is pain;
the location of the paindepends
on the location of the fracture. The symptoms of
osteoporosis in men are similar to the symptoms
of osteoporosis in women. Fractures
of the spine (vertebra) can cause severe "band-like"pain that
radiates from the back to the sides of the body. |
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Over the years, repeated spinal fractures can
lead to chronic lower
back pain as
well as loss of height and/or curving of the
spine due to collapse of the vertebrae. The
collapse gives individuals a hunched-back
appearance of the upper back, often called a
"dowager hump" because it commonly is seen in
elderly women. A fracture that occurs during the
course of normal activity is called a minimal
trauma, or stress fracture.
For example, some patients with osteoporosis
develop stress fractures of the feet while walking or
stepping off a curb. Hip fractures typically
occur as a result of a fall. With osteoporosis,
hip fractures can occur as a result of trivial
accidents. Hip fractures also may heal slowly or
poorly after surgical repair because of poor
healing of the bone. |
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What factors determine bone strength? Bone
mass (bone density) is determined by the amount
of bone present in the skeletal structure.
Generally, the higher the bone density, the
stronger the bones. Bone density is greatly
influenced by genetic factors, which in turn are
sometimes modified by environmental factors and
medications. For example, men have a higher bone
density than women, and African Americans have a
higher bone density than Caucasian or Asian
Americans. Normally, bone density accumulates
during childhood and reaches a peak by around
age 25. Bone density then is maintained for
about 10 years. After age 35, both men and women
will normally lose 0.3%-0.5% of their bone
density per year as part of the aging process.
Estrogen is important in maintaining bone
density in women. When estrogen levels drop
after menopause,
loss of bone density accelerates. During the
first five to 10 years after menopause, women
can suffer up to 2%-4% loss of bone density per
year! This can result in the loss of up to
25%-30% of their bone density during that time
period. The accelerated bone loss after
menopause is a major cause of osteoporosis in
women, referred to as postmenopausal
osteoporosis. |
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What are osteoporosis risk factors and causes? The
following are factors that will increase the
risk of developing osteoporosis: |
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Female
gender
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Caucasian
or Asian race
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Thin and
small body frame
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Family
history of
osteoporosis (for example, having a mother
with an osteoporotic hip fracture doubles
your risk of hip fracture)
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Personal
history of fracture as an adult
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Cigarette smoking
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Excessive
alcohol consumption
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Lack of exercise
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Diet low in
calcium
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Poor nutrition and
poor general health
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Malabsorption (nutrients
are not properly absorbed from the
gastrointestinal system) from conditions
such as celiac
sprue.
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Low estrogen levels in women (such as occur
in menopause or with early surgical removal
of both ovaries).
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Low
testosterone levels in
men (hypogonadism)
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Chemotherapy that
can cause early menopause due to its toxic
effects on the ovaries
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Amenorrhea (loss
of the menstrual period) in young women
associated with low estrogen and
osteoporosis; amenorrhea can occur in women
who undergo extremely vigorous exercise training
and in women with very low body fat,
for example, women with anorexia
nervosa
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Chronic
inflammation, due to chronic diseases such
as rheumatoid
arthritis or
liver diseases
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Immobility,
such as after a stroke,
or from any condition that interferes with
walking
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Hyperthyroidism, a condition wherein too
much thyroid hormone is produced by the
thyroid gland (as in Grave's disease) or is
ingested as thyroid hormone medication
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Hyperparathyroidism is
a disease wherein there is excessive
parathyroid hormone production by the
parathyroid gland, a small gland located
near or within the thyroid gland. Normally,
parathyroid hormone maintains blood calcium
levels by, in part, removing calcium from
the bone. In untreated hyperparathyroidism,
excessive parathyroid hormone causes too
much calcium to be removed from the bone,
which can lead to osteoporosis.
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When
vitamin D is lacking, the body cannot
absorb adequate amounts of calcium from the
diet to prevent osteoporosis. Vitamin D
deficiency can result from lack of
intestinal absorption of the vitamin such as
occurs in celiac sprue and primary
biliary cirrhosis.
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Certain
medications can cause osteoporosis. These
include long-term use ofheparin (a
blood thinner), antiseizure medications such
as phenytoin (Dilantin)
and phenobarbital, and long-term use of oral
corticosteroids (such asprednisone).
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How is osteoporosis diagnosed? A
routine X-ray can reveal osteoporosis of the
bone because the bones appear much thinner and
lighter than normal bones. Unfortunately, by the
time X-rays can detect osteoporosis, at least
30% of the bone has already been lost. In
addition, X-rays are not accurate indicators of
bone density. Thus, the appearance of the bone
on X-ray often is affected by variations in the
degree of exposure of the X-ray film. The
National Osteoporosis Foundation, the American
Medical Association, and other major medical
organizations recommend a dual-energy X-ray
absorptiometry scan (DXA, formerly known as DEXA)
for diagnosing osteoporosis. DXA measures bone
density in the hip and the spine. The test takes
only five to 15 minutes to perform, exposes
patients to very little radiation (less than
one-tenth to one-hundredth of the amount used on
a standard chest X-ray), and is quite precise.
The bone density of the patient is compared to
the average peak bone density of young adults of
the same sex and race. This score is called the
"T score," and it expresses the bone density in
terms of the number of standard deviations (SD)
below peak young adult bone mass. |
- Osteoporosis is defined as a bone
density T score of -2.5 or below.
- Osteopenia (between normal and
osteoporosis) is defined as bone density T
score between -1 and -2.5.
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It is important to note that
while Osteopenia is considered a lesser degree
of bone loss than osteoporosis, it nevertheless
can be of concern when it is associated with
other risk factors (such as smoking,
cortisone steroid usage, rheumatoid arthritis,
family history of osteoporosis, etc.) that can
increase the chances for developing vertebral,
hip, and other fractures. In this setting,
Osteopenia may require medication as part of the
treatment program. |
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What is the treatment for osteoporosis, and can
osteoporosis be prevented? The
goal of treatment of osteoporosis is the
prevention of bone fractures by reducing bone
loss or, preferably, by increasing bone density
and strength. Although early detection and
timely treatment of osteoporosis can
substantially decrease the risk of future
fractures, none of the available treatments for
osteoporosis are complete cures. In other words,
it is difficult to completely rebuild bone that
has been weakened by osteoporosis. Therefore,
prevention of osteoporosis is as important as
treatment. The following are osteoporosis
treatment and prevention measures: |
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1. Lifestyle
changes,
including quitting
cigarette smoking, curtailing excessive alcohol
intake, exercising regularly, and consuming a
balanced diet with adequate calcium and vitamin
D |
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2. Medications that stop bone loss and increase
bone strength,
such
asalendronate, risedronate, raloxifene,
ibandronate, calcitonin, zoledronate and
denosumab. |
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3. Medications that increase bone
formation such
as teriparatide (Forteo) |
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Lifestyle changes: Exercise,
quitting cigarettes, and curtailing alcohol: Exercise
has a wide variety of beneficial health effects.
However, exercise does not bring about
substantial increases in bone density. The
benefit of exercise for osteoporosis has mostly
to do with decreasing the risk of falls,
probably because balance is improved and/or
muscle strength is increased. Research has not
yet determined what type of exercise is best for
osteoporosis or for how long it should be
continued. Until research has answered these
questions, most doctors
recommend weight-bearing exercise, such as walking,
preferably daily. |
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A
word of caution about exercise: It
is important to avoid exercises that
can injure already weakened bones. In patients
over 40 and those with heart
disease, obesity, diabetes mellitus,
and high
blood pressure, exercise should be prescribed
and monitored by physicians. Extreme levels of
exercise (such as marathon running) may not be
healthy for the bones. Marathon running in young
women that leads to weight
loss and
loss of menstrual periods can actually promote
osteoporosis. Smoking one pack of cigarettes per
day throughout adult life can itself lead to
loss of 5%-10% of bone mass. Smoking cigarettes
decreases estrogen levels and can lead to bone
loss in women before menopause. Smoking
cigarettes also can lead to earlier menopause.
In postmenopausal women, smoking is linked with
increased risk of osteoporosis. Data on the
effect of regular consumption of alcohol and
caffeine on
osteoporosis is not as clear as with exercise
and cigarettes. In fact, research regarding
alcohol and caffeine as risk factors for
osteoporosis shows widely varying results and is
controversial. Certainly, their effects are not
as great as other factors. Nevertheless,
moderation of both alcohol and caffeine is
prudent. |
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Medications that prevent bone loss and breakdown:
Currently, the most effective medications for
osteoporosis that are approved by the FDA are
antiresorptive agents, which decrease the
removal of calcium from bones.
The bone is a living dynamic
structure; it is constantly being built and
removed (resorbed). This process is an essential
part of maintaining the normal calcium level in
the blood and serves to repair tiny cracks in
the bones that occur with normal daily activity
and to remodel bone based on the physical
stresses placed on the bone. Osteoporosis
results when the rate of bone resorption exceeds
the rate of bone rebuilding. Antiresorptive
medications inhibit removal of bone (resorption),
thus tipping the balance in favor of bone
rebuilding and increasing bone density. HRT is
one example of an antiresorptive agent. Others
include alendronate (Fosamax), risedronate(Actonel),raloxifene (Evista), ibandronate (Boniva), calcitonin (Calcimar),
zoledronate (Reclast), and denosumab (Prolia). |
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Bisphosphates:
Bisphosphonates
decrease the risk of hip fracture, wrist fracture, and spine fracture in
people with osteoporosis. Alendronate (Fosamax), risedronate (Actonel),
ibandronate (Boniva), and zoledronate (Reclast) are bisphosphonates. To
reduce side effects and to enhance absorption of the medicine, all
bisphosphonates taken by mouth (orally) should be taken in the morning,
on an empty stomach, 30 minutes before breakfast, and with at least 8
ounces (240 ml) of water (not juice). This improves the absorption of
the biphosphonate. Taking the pill sitting or standing (as well as
drinking adequate amounts of liquids) minimizes the chances of the pill
being lodged in the esophagus, where it can cause ulceration and
scarring. Patients should also remain upright for at least 30 minutes
after taking the pill to avoid reflux of the pill into the esophagus.
Newer intravenous bisphosphonates, such as ibandronate (Boniva) and
zoledronate (Reclast), bypass the potential esophagus and stomach
problems. Food,
calcium, iron supplements, vitamins with minerals, or antacids
containing calcium, magnesium,
or aluminum can
reduce the absorption of oral bisphosphonates, thereby resulting in loss
of effectiveness. Therefore, oral bisphosphonates should be taken with
plain water only in the morning before breakfast. Also, no food or
drink should be taken for at least 30 minutes afterward. |
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Alendronate (Fosamax):
Alendronate (Fosamax)
is a biphosphonate antiresorptive medication. Alendronate is approved
for the prevention and treatment of postmenopausal osteoporosis as well
as for osteoporosis that is caused by cortisone-related medications (glucocorticoid-induced
osteoporosis). Alendronate has been shown to increase bone density and
reduce fractures in the spine, hips, and arms. Fosamax is taken by mouth
once a week to prevent and treat postmenopausal osteoporosis.
Alendronate is the first osteoporosis medication also approved for
increasing bone density in men with osteoporosis, either in a daily or a
weekly dosing schedule. Fosamax generally is well tolerated with few
side effects. One side effect of alendronate is irritation of the
esophagus (the food pipe
connecting the mouth to the stomach). Inflammation of the esophagus
(esophagitis) and ulcers of the esophagus have been reported
infrequently with alendronate use. |
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Risedronate (Actonel):
Risedronate (Actonel)
is another bisphosphonate antiresorptive
medication. Like alendronate, this drug is approved for the prevention
and treatment of postmenopausal osteoporosis as well as for osteoporosis
that is caused by cortisone-related medications (glucocorticoid-induced
osteoporosis). Risedronate is chemically different from alendronate and
has less likelihood of causing esophageal irritation. Risedronate also
is more potent in preventing the resorption of bone than alendronate. |
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Ibandronate (Boniva):
Ibandronate (Boniva)
is a bisphosphonate for prevention and treatment of postmenopausal
osteoporosis. It is available in formulations for both daily and monthly
oral use as well as for intravenous use every three months. |
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Zoledronate (Reclast):
Zoledronate (Reclast)
is a unique intravenous bisphosphonate antiresorptive medication that is
given once every year. This formulation seems to have very good ability
to strengthen bones and prevent fractures of both spinal and non-spinal
bones. The convenience of once-a-year dosing is obvious. As with all
bisphosphonates, patients taking Reclast must be taking adequate calcium
and vitamin D prior to and after infusion of the medication for optimal
results. Generally, patients are given acetaminophen (Tylenol)
the day of the infusion and for several days afterward to prevent
occasional minor muscle and joint aches. The infusion lasts
approximately 20-30 minutes. Reclast is used to treat and prevent
osteoporosis in postmenopausal women and increases bone mass in men with
osteoporosis. Reclast is also used to treat and prevent steroid-induced
osteoporosis (glucocorticoid-induced osteoporosis). Reclast reduces risk
of fractures after a low-trauma hip fracture. Reclast should not be used
during or prior to pregnancy. |
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