Bone Voyage
Keeping bones healthy and preventing osteoporosis is not a quick trip but a lifelong journey.
Keeping bones healthy might seem like a far-off concern to many-something
to address long after the arrival of a first gray hair or wrinkle. After all,
the effects of thinning bones usually 
lie low until the retirement years. What often gets lost, though,
is the hard truth: The origins of osteoporosis may reach as far
back as childhood.
That is why Keck School of Medicine of USC doctors tout the importance
of good bone health for all patients, regardless of age. They
encourage a balanced diet and regular exercise to build and maintain
bone, screen patients for the earliest signs of bone thinning,
and when they diagnose osteoporosis, ensure
that patients have access to the latest treatments.
Although all bones gradually lose density as we age, osteoporosis
is a condition in which bones are so weak and thin that they
break easily. Rather than simply an inevitable part of getting
older, osteoporosis is a disease that can wreak daily, debilitating
pain through bone fractures-and even lead to deadly complications.
But it need not be so.
"It's much easier and better to prevent osteoporosis than
to deal with it when you have it," says Robert K. Rude,
M.D., professor of medicine at the Keck School of Medicine and
an osteoporosis specialist. "There are things we can do
to help."
Bone primer
Though they are rigid and sturdy, bones are far from lifeless.
They may thrive-or decline-just like the tissues around them.
Bones are mostly made of collagen, which forms a soft scaffold
within bone, and calcium phosphate, a mineral that strengthens
and hardens that scaffold. The body constantly renews old bone
by tearing away these materials and building them back up.
The more effectively the body does this, the healthier the bones.
"Special cells called osteoclasts start the process by biting
on bone and secreting acid into it," explains Baruch Frenkel,
Ph.D., D.M.D., assistant professor of orthopaedic surgery and
biochemistry and molecular biology at the Keck School. "It
is dissolved like stone."
Then, cells called osteoblasts come in to create new bone. "As
the osteoclast moves along, the osteoblast follows behind it,
refilling the trench," he says. The two cells, operating
in tandem, form a bone construction crew that works night and
day, day after day.
The give-and-take creates a fragile balance in the bones.
"Over the period of a year, every piece of your bone undergoes
this process," Frenkel says. "But when this process
is impaired, you get osteoporosis."
Strengthening bones
During childhood and adolescence, bones grow bigger and become
denser because osteoblasts add more bone than osteoclasts remove.
This growth peaks in the 20s, when bones are their densest.
The denser the bones are when they reach their peak, the more
they can stand to lose later and still remain strong. Although
genetics determines much of this density, physicians know that
getting enough calcium through diet plays a big part too. That
is why internists such as Betsy Felser, M.D., assistant professor
of clinical medicine, asks even her youngest patients about their
calcium intake.
Consuming calcium provides raw material for new bone during youth
and beyond. Yet studies show that fewer than 25 percent of teenage
girls, for instance, get the daily calcium they need. (And girls
who have eating and exercise disorders can even experience early
osteoporosis.)
But in the 30s, the balance shifts. Osteoclasts slowly begin
removing more bone than the tiring osteoblasts can add, causing
a quiet weakening in bones that continues over the rest of a
lifetime.
Before menopause, the female hormone estrogen protects women's
bones. When menopause begins, though, estrogen levels drop and
bone loss accelerates. Some women lose as much as 30 percent
of their bone mass in the first five years after menopause.
"Between diet and supplements, a premenopausal woman should
get 1,000 milligrams a day of calcium," Felser says. "After
menopause, calcium should go up to between 1,200 and 1,500 milligrams
a day."
She recommends that patients swallow a calcium carbonate supplement
with vitamin D along with lunch or dinner. Calcium chews are
a good option, too.
Older bones
Not long ago, a dowager's hump, the slumping back that often
characterizes osteoporosis, was just a sign of getting older.
In today's society, though, more people-both within and outside
the health professions-appreciate that prevention and early diagnosis
can head off the disease before the bones of the spine can crumble.
Rude, an endocrinologist specializing in osteoporosis, starts
by making sure older patients are getting the most out of their
diet.
When seniors stay indoors and out of the sun, Rude says, they
often do not get enough vitamin D, which the intestines need
to absorb calcium. "I always try to ensure that patients
get between 400 and 800 milligrams of vitamin D a day,"
he says. "It's never too late for good nutrition."
Although osteoporosis afflicts four times as many women as men,
about 2 million American men also have the disease-so men should
watch calcium intake, too, Rude says. Men older than age 50 should
consume more than 1,200 mg of calcium a day.
Moreover, one in eight men will have an osteoporosis-related
fracture during their lifetime, according to the National Osteoporosis
Foundation. Although the rate of hip fractures in women is two
to three times higher than that in men, men are more likely to
die within a year after a hip break than women, Rude says. Unfortunately,
many men are not tested for the disease, even after a fracture.
Some theorize that losing testosterone later in life spurs male bone loss.
"One third of men develop subnormal levels of testosterone as they age,"
says Loren Lipson, 
M.D., Keck
School associate professor of medicine and chief of geriatric medicine. "We're
still not sure of the correlation with osteoporosis, though."
Bones at risk
Physicians usually customize recommendations for patients with
a family history of osteoporosis or those who have endocrine
disorders such as hyperthyroidism, an excessive amount of thyroid
hormone in the body, which can speed up bone loss.
Risks also are linked to certain gastrointestinal and bone marrow
diseases, as well as prolonged use of certain drugs including
steroids such as cortisone or prednisone, which are commonly
used to treat rheumatoid arthritis, asthma, inflammatory bowel
disease and other disorders.
Smoking, a thin body build, Asian or Caucasian ethnicity and
excessive alcohol use-more than two drinks a day-also raise risk.
Building bone
Along with diet, Felser suggests weight-bearing exercise to her
patients, such as taking regular walks wearing light wrist weights.
Weight-bearing exercise helps build bone. It cannot reverse lost
bone mass in older people, Rude says, "but exercise does
improve agility, and that is important, because that can help
people from falling and breaking a bone."
And fractures are the prime danger of osteoporosis, which may
go undetected until the first bone snaps.
"The most common break is a fracture of the vertebrae, which
may cause chronic pain and hunching," says Lipson. "The
second most common is a broken hip."
Not only do these fractures hurt, but subsequent complications-bleeding,
blood clots, heart attacks, pneumonia and the like-may be deadly.
Even a violent sneeze or a bump against a table can crunch fragile
vertebrae
Bone protection
To stave off osteoporosis before it happens, USC physicians offer
regular bone mineral density tests to measure density in the
spine, wrist or hip. The National Osteoporosis Foundation recommends
these painless scans for all women ages 65 and older and postmenopausal
women under age 65 who have at least one risk factor for osteoporosis.
Postmenopausal women who break a bone also should be tested.
The Osteoporosis Foundation has no recommendation for men or
younger women, but the International Society for Clinical Densitometry
published guidelines in October 2002 to help physicians decide
when to test bone density in male patients. They suggest testing
for men who have suffered broken bones from low-impact accidents
as well as men with significant osteoporosis risk factors. Some
believe all men over age 70 should be screened; it is up to physicians,
however, to recommend testing for each patient depending on individual
risk factors.
Depending on results, called a "T score," physicians
create a plan for bone health, which may span from continued
regular checkups to dietary changes to medicines.
Fortunately, four drug treatments today are approved to slow
osteoclasts' appetite and the bone loss it causes: bisphosphanate
drugs such as Fosamax or Actonel; estrogen; selective estrogen
receptor modulators, or SERMs, such as Evista, and calcitonin,
a nasal spray. None of these can stoke bone-building cells into
returning bone already lost, but they can stem the tide.
Bisphosphanates have shown the most protection against all types
of fractures, notes Rude, who is running a clinical trial for
an experimental once-a-year infused bisphosphanate called zoledronic
acid. But physicians may prescribe other drugs as appropriate
for each patient.
In late 2002, federal officials approved another promising alternative:synthetic
human parathyroid hormone, or PTH, injections under the trade
name Forteo.
Rude hopes for the day when physicians
can prescribe drugs that eradicate osteoporosis altogether. PTH is the first
drug that seems to actually increase bone density, at least for a while.
"Eventually, we'll probably look at giving a combination
of drugs,"
Rude says, "those that both build bone and keep you from
losing it."
In the future, say Rude and other physicians, better awareness
of osteoporosis, testing and preventive drugs may keep the disease
from disabling so many-and help to build better bones from the
start.
For more information about osteoporosis prevention and treatment,
call 1-800-USC-CARE (1-800-872-2273).
Back Next Index