"Osteoporosis Overview"
Osteoporosis, or porous bone, is a disease characterized
by low bone mass and structural deterioration of bone tissue, leading to
bone fragility and an increased susceptibility to fractures of the hip,
spine, and wrist. Men as well as women suffer from osteoporosis, a disease
that can be prevented and treated.
Facts and Figures
* Osteoporosis
is a major public health threat for 28 million Americans, 80% of whom are
women.
* In the U.S.
today, 10 million individuals already have osteoporosis and 18 million more
have low bone mass, placing them at increased risk for this disease.
* One out of
every two women and one in eight men over 50 will have an osteoporosis-related
fracture in their lifetime.
* More than
2 million American men suffer from osteoporosis, and millions more are
at risk. Each year, 80,000 men suffer a hip fracture and one-third of these
men die within a year.
* Osteoporosis
can strike at any age.
* Osteoporosis
is responsible for more than 1.5 million fractures annually, including
300,000 hip fractures, and approximately 700,000 vertebral fractures, 250,000
wrist fractures, and more than 300,000 fractures at other sites.
* Estimated
national direct expenditures (hospitals and nursing homes) for osteoporosis
and related fractures is $14 billion each year.
What is Bone?
Bone is living, growing tissue. It is made mostly of
collagen, a protein that provides a soft framework, and calcium phosphate,
a mineral that adds strength and hardens the framework. This combination
of collagen and calcium makes bone strong yet flexible to withstand stress.
More than 99% of the body's calcium is contained in the bones and teeth. The remaining 1% is
found in the blood.
Throughout your lifetime, old bone is removed
(resorption)
and new bone is added to the skeleton (formation). During childhood and
teenage years, new bone is added faster than old bone is removed. As a result, bones become larger, heavier, and denser. Bone
formation continues at a pace faster than resorption until peak bone mass
(maximum bone density and strength) is reached during the mid-20s.
After age 30, bone resorption slowly begins to exceed
bone formation. Bone loss is most rapid in the first few years after menopause
but persists into the postmenopausal years. Osteoporosis develops when
bone resorption occurs too quickly or if replacement occurs too slowly.
Osteoporosis is more likely to develop if you did not reach optimal bone
mass during your bone building years.
Risk Factors
Certain factors are linked to the development of osteoporosis
or contribute to an individual’s likelihood of developing the disease.
These are called “risk factors.” Many people with osteoporosis have several
of these risk factors, but others who develop osteoporosis have no identified
risk factors. There are some risk factors that you cannot change, and others
that you can:
Risk factors you cannot change -
* Gender -
Your chances of developing osteoporosis are greater if you are a woman.
Women have less bone tissue and lose bone more rapidly than men because
of the changes involved in menopause.
* Age - the
older you are, the greater your risk of osteoporosis. Your bones become
less dense and weaker as you age.
* Body size
- Small, thin-boned women are at greater risk.
* Ethnicity
- Caucasian and Asian women are at highest risk. African-American and Hispanic
women have a lower but significant risk.
* Family history - Susceptibility to fracture may be, in part, hereditary.
People whose parents have a history of fractures also seem to have reduced bone
mass and may be at risk for fractures.
Risk factors you can change - Sex
hormones: abnormal absence of menstrual periods (amenorrhea), low estrogen level
(menopause), and low testosterone level in men.
* Anorexia
*A lifetime
diet low in calcium and vitamin D.
* Use of certain
medications, such as glucocorticoids or some anticonvulsants.
* An inactive
lifestyle or extended. bed rest.
* Cigarette
smoking.
* Excessive
use of alcohol.
Prevention
To reach optimal peak bone mass and continue building
new bone tissue as you get older, there are several factors you
should consider:
Calcium. An inadequate supply of calcium over the
lifetime is
thought to play a significant role in contributing to
the
development of osteoporosis. Many published studies show
that
low calcium intakes appear to be associated with low
bone mass, rapid bone loss, and high fracture rates.
National nutrition
surveys have shown that many people consume less than
half the amount of calcium recommended to build and maintain healthy bones. Good sources of calcium include low fat dairy
products, such as milk, yogurt, cheese and ice cream; dark green,
leafy vegetables, such as broccoli, collard greens, bok choy
and spinach; sardines and salmon with bones; tofu; almonds;
and foods fortified with calcium, such as orange juice, cereals
and breads.
Depending upon how much calcium you get each
day from food, you may need to take a calcium supplement. Calcium needs change during one’s lifetime.
The body’s demand for calcium is greater during childhood
and adolescence, when the skeleton is growing rapidly, and during pregnancy
and breastfeeding. Postmenopausal women and older men also
need to consume more calcium.
This may be caused by inadequate amounts of vitamin D, which is necessary for intestinal absorption of calcium. Also, as you age, your body becomes
less efficient at absorbing calcium and other nutrients. Older
adults also are more likely to have chronic medical problems
and to use medications that may impair calcium absorption.
Vitamin D. Vitamin D plays an important role in
calcium
absorption and in bone health. It is synthesized in the
skin
through exposure to sunlight. While many people are able
to
obtain enough vitamin D naturally, studies show that
vitamin D
production decreases in the elderly, in people who are
housebound, and during the winter. These individuals
may
require vitamin D supplementation to ensure a daily intake
of
between 400 to 800 IU of vitamin D. Massive doses are
not
recommended.
Exercise. Like muscle, bone is living tissue that
responds to
exercise by becoming stronger. The best exercise for
your bones is weight-bearing exercise, that forces you to work against gravity. These exercises include walking, hiking, jogging, stair-climbing, weight training, tennis, and dancing.
Smoking. Smoking is bad for your bones as well
as for your
heart and lungs. Women who smoke have lower levels of
estrogen compared to nonsmokers and frequently go through
menopause earlier. Postmenopausal women who smoke may
require higher doses of hormone replacement therapy and
may
have more side effects. Smokers also may absorb less
calcium
from their diets.
Alcohol. Regular consumption of 2 to 3 ounces a
day of alcohol
may be damaging to the skeleton, even in young women
and
men. Those who drink heavily are more prone to bone loss
and
fractures, both because of poor nutrition as well as
increased risk of falling.
Medications that cause bone loss. The long-term
use of
glucocorticoids (medications prescribed for a wide range
of
diseases, including arthritis, asthma, Crohn’s disease,
lupus, and other diseases of the lungs, kidneys, and liver) can
lead to a loss of bone density and fractures.
Other forms of drug therapy
that can cause bone loss include long-term treatment with
certain antiseizure drugs, such as phenytoin (Dilantin), barbiturates, and valproate (Depakote); gonadotropin releasing hormone (GnRH) analogs used to treat endometriosis; excessive
use of aluminum-containing antacids; certain cancer treatments;
and excessive thyroid hormone. It is important to discuss
the use of these drugs with your physician, and not to stop or alter
your medication dose on your own.
Prevention Medications. Various medications are
available for the prevention, as well as treatment, of osteoporosis. See
section entitled “Therapeutic Medications.”
Symptoms. Osteoporosis is often called the “silent
disease” because bone loss occurs without symptoms. People may not know that they
have osteoporosis until their bones become so weak that a
sudden strain, bump, or fall causes a hip fracture or a vertebra to
collapse. Collapsed vertebra may initially be felt or seen in the
form of severe back pain, loss of height, or spinal deformities such
as kyphosis, or severely stooped posture.
Detection. Following a comprehensive medical assessment,
your doctor may recommend that you have your bone mass measured. Bone
mineral density (BMD) tests measure bone density in the spine,
wrist, and/or hip (the most common sites of fractures due to osteoporosis),
while others measure bone in the heel or hand. These tests
are painless, noninvasive, and safe.
Bone density tests can:
* Detect low
bone density before a fracture occurs. Confirm a diagnosis of osteoporosis
if you have already fractured.
* Predict your
chances of fracturing in the future.
* Determine
your rate of bone loss and/or monitor the effects of treatment if the test
is conducted at intervals of a year or more.
Treatment
A comprehensive osteoporosis treatment program includes a
focus on proper nutrition, exercise, and safety issues to prevent
falls that may result in fractures. In addition, your physician may
prescribe a medication to slow or stop bone loss, increase bone density,
and reduce fracture risk.
Nutrition. The foods we eat contain a variety of
vitamins, minerals, and other important nutrients that help keep our bodies
healthy. All of these nutrients are needed in a balanced proportion.
In particular, calcium and vitamin D are needed for strong bones as
well as for your heart, muscles, and nerves to function properly.
(See Prevention section for recommended amounts of calcium.)
Exercise. Exercise is an important component of
an osteoporosis prevention and treatment program. Exercise not only improves
your bone health, but it increases muscle strength, coordination,
and balance and leads to better overall health. While exercise
is good for someone with osteoporosis, it should not put any sudden
or excessive strain on your bones. As extra insurance against fractures,
your doctor can recommend specific exercises to strengthen
and support your back.
The Therapeutic Role of Medication. Currently,
estrogen,
calcitonin, and alendronate are approved by the U. S.
Food and Drug Administration (FDA) for the treatment of postmenopausal
osteoporosis. Estrogen, raloxifene and alendronate are
approved for the prevention of the disease. Estrogen.
Estrogen replacement therapy (ERT) has been
shown to reduce bone loss, increase bone density in both the
spine and hip, and reduce the risk of hip and spinal fractures
in postmenopausal women.
ERT is administered most commonly
in the form of a pill or skin patch and is effective even
when started after age 70. When estrogen is taken alone, it can increase
a woman’s risk of developing cancer of the uterine lining (endometrial cancer).
To eliminate this risk, physicians
prescribe the hormone progestin in combination with estrogen (hormone replacement therapy or HRT) for those women who have
not had a hysterectomy. ERT/HRT relieves menopause symptoms and has been shown to have beneficial effects on both the
skeleton and heart.
Experts recommend ERT for women at high risk for
osteoporosis. ERT is approved for both the prevention
and
treatment of osteoporosis. ERT is especially recommended
for
women whose ovaries were removed before age 50.
Estrogen
replacement should also be considered by women who have
experienced natural menopause and have multiple osteoporosis
risk factors, such as early menopause, family history
of
osteonorosis, or below normal bone mass for their age.
As with
all drugs, the decision to use estrogen should be made
after
discussing the benefits and risks and your own situation
with
your doctor.
Raloxifene. Raloxifene (brand name
Evista@) is
a drug that was
recently approved for the prevention of osteoporosis.
It is from a new class of drugs called Selective Estrogen Receptor
Modulators (SERMs) that appear to prevent bone loss at
the
spine, hip, and total body.
Raloxifene’s effect on the
spine does
not appear to be as powerful as either estrogen replacement
therapy or alendronate, but its effect on the hip and
total body are more comparable. While side-effects are not common with
raloxifene, those reported include hot flashes and deep
vein
thrombosis, the latter of which is also associated with
estrogen
therapy. Additional research studies on raloxifene will
be
ongoing for several more years.
Alendronate. Alendronate (brand name
Fosamax) is
a
medication from the class of drugs called bisphosphonates.
Like
estrogen, alendronate is approved for both the prevention
and
treatment of osteoporosis. In postmenopausal women with
osteoporosis, the bisphosphonate alendronate reduces
bone loss, increases bone density in both the spine and hip, and
reduces the risk of both spine fractures and hip fractures.
Side
effects from alendronate are uncommon, but may include abdominal or musculoskeletal pain, nausea, heartburn, or irritation
of the esophagus. The medication should be taken on an empty
stomach and with a full glass of water first thing in the morning.
After taking alendronate, it is important to wait in an upright
position for at least one-half hour, or preferably one hour, before
the first food, beverage, or medication of the day.
Calcitonin. Calcitonin is a naturally occurring
non-sex hormone
involved in calcium regulation and bone metabolism. In
women
who are at least 5 years beyond menopause, calcitonin
slows
bone loss, increases spinal bone density, and according
to
anecdotal reports, relieves the. pain associated with
bone
fractures. Calcitonin reduces the risk of spinal fractures
and may
reduce hip fracture risk as well.
Studies on fracture
reduction are ongoing. Calcitonin is currently available as an injection
or nasal spray. While it does not affect other organs or systems
in the body, injectable calcitonin may cause an allergic reaction
and unpleasant side effects including flushing of the face
and hands, urinary frequency, nausea., and skin rash. The only side
effect reported with nasal calcitonin is a runny nose.
Fall prevention is a special concern for men and
women with
osteoporosis. Falls can increase the likelihood of fracturing
a bone in the hip, wrist, spine or other part of the skeleton.
In addition to the environmental factors listed below, falls can also be
caused by impaired vision and/or balance, chronic diseases that
impair mental or physical functioning, and certain medications, such
as sedatives and antidepressants.
It is important that individuals
with osteoporosis be aware of any physical changes they may be experiencing
that affect their balance or gait, and that they discuss these
changes with their health care provider.
Some tips to help eliminate the environmental factors
that lead to falls include:
Outdoors. Use a cane or walker for added stability;
wear
rubber-soled shoes for traction; walk on grass when sidewalks
are slippery; in winter, carry salt or kitty litter to
sprinkle on
slippery sidewalks; be careful on highly polished floors
that
become slick and dangerous when wet. Use plastic or carpet
runners when possible.
Indoors. Keep rooms free of clutter, especially
on floors; keep
floor surfaces smooth but not slippery; wear supportive,
low-healed shoes even at home; avoid walking in socks,
stockings, or slippers; be sure carpets and area rugs
have
skid-proof backing or are tacked to the floor; be sure
stairwells
are well lit and that stairs have handrails on both sides;
install
grab bars on bathroom walls near tub, shower, and toilet;
use a
rubber bath mat in shower or tub; keep a flashlight with
fresh
batteries beside your bed; if using a step stool for
hard to reach
areas, use a sturdy one with a handrail and wide steps;
add
ceiling fixtures to rooms lit by lamps. Consider purchasing
a
cordless phone so that you don’t have to rush to answer
the
phone when it rings or you can call for help if you do
fall.
|