Within the next 25 years, roughly 20% of the U.S. population (~71 million people) will be ¡Ý65 years.2 Current estimates indicate that 10 million Americans have osteoporosis and 34 million are at risk of developing it.1 By 2020, those numbers are expected to reach 14 million and 47 million, respectively.1
Osteoporosis poses a significant health risk in the United
States, particularly among women, and the problem is expected to
only intensify as the population ages, according to a recent
Surgeon General's Report.
The scope of the problem
Within the next 25 years, roughly 20% of the U.S. population
(~71 million people) will be ≥65 years.
Current estimates indicate that 10 million Americans have
osteoporosis and 34 million are at risk of developing it.
By 2020, those numbers are expected to reach 14 million and 47
Each year, 1.5 million adults suffer an osteoporotic fracture.
According to the National Osteoporosis Foundation, a woman's risk
of hip fracture is equal to her risk of breast, uterine, and
ovarian cancer combined.
Nearly 3 times as many women have an osteoporotic fracture as have
a heart attack.
For the approximately 300,000 of those who suffer a hip fracture,
the outcome can be devastating.
The 1-year mortality rate for people >50 years who experience a
hip fracture is approximately 24%.
For many of those who do survive, however, life is never the same.
At 6 months, only 15% of hip fracture patients can walk across a
Another 20% who were ambulatory before the injury may require
long-term care as a result,
and up to 80% may be unable to carry out at least 1 independent
activity of daily living following a hip fracture.
In addition to hip factures, osteoporotic vertebral factures, of
which there are approximately 750,000 per year,
can result in chronic pain and disability.
"We're clearly not getting to all the patients who need
treatment," said John Jenkins, Director of Product Management at
Hologic Inc. (Bedford, MA). "The large population of baby boomers
are reaching, or have just passed, menopause. They are now in the
target period for osteoporosis testing. With the number of patients
who have osteoporosis now, factoring in the changing demographics
through 2020, it's clear that it is a growing health concern."
The financial burden of bone disease on the healthcare system is
enormous. In 2002, it was estimated that the national direct-care
expenditures for osteoporotic factures was $18 billion.
This number can only be expected to rise. In his recent report, the
Surgeon General warned, "Due primarily to the aging of the
population and the previous lack of focus on bone health, the
number of hip fractures in the United States could double or even
triple by the year 2020."
Risk factors for developing osteoporosis
In addition to being female and of advanced age, risk factors
for developing osteoporosis include: history of fracture after age
50, low bone mass, being thin or having a small frame, a family
history of osteoporosis or fracture in a close relative, estrogen
deficiency, amenorrhea, anorexia nervosa, low lifetime intake of
calcium, Vitamin D deficiency, an inactive lifestyle, the presence
of certain chronic medical conditions, and the use of certain
medications, among others.
What can be done?
Creation of maximum bone mass early in life and prevention of
bone loss later in life are the keys to long-term skeletal health.
Approximately 98% of a woman's bone mass is formed before the age
of 20; therefore, building a healthy skeletal system during
childhood and adolescence is the best defense against later
This process can be aided by a lifetime diet high in calcium and
Vitamin D, performance of weight-bearing exercise, and avoidance of
smoking and excessive alcohol intake.
One of the greatest challenges with osteoporosis is that the
first recognized symptom is often a fracture. Therefore, bone
mineral density (BMD) testing before a fracture occurs is extremely
important for the diagnosis of osteoporosis and the prevention of
fractures. The National Osteoporosis Foundation recommends that all
women over the age of 65 undergo BMD testing regardless of their
They also recommend testing for younger, postmenopausal women with
≥1 risk factor other than gender and age, and postmenopausal women
who present with any facture.
For those over the age of 65, Medicare covers the cost of BMD
testing every 2 years.
Many imaging centers suggest that patients undergo mammography
and BMD testing during the same visit. "The women who need
mammograms also need bone density studies," noted Jenkins.
Advances in osteoporosis assessment technology
A variety of technologies have been used to assess skeletal
health, the most common of these is dual-energy X-ray
absorptiometry (DXA), which measures the spine, hip, or total body.
Recent advances in this imaging technology have made the assessment
of skeletal health faster and more accurate.
The Discovery QDR Series bone densitometer (Hologic Inc.,
Bedford, MA) features High Definition Instant Vertebral Assessment
(IVA), which takes a 10second scan of the lumbar thoracic spine to
visualize vertebral deformities (Figure 1). "This helps classify
additional patients as osteoporotic even with border-line results
by typical BMD," said Jenkins. "With this, the physician can take
rapid images and determine whether or not there is a vertebral
The system also features CAD
, a computer-aided detection system. "With CAD
, the user clicks on a vertebral body," explained Jenkins. "The
software outlines the vertebral body and takes a quantitative
measurement that compares the anterior height and the medial height
of the vertebral body to the posterior height. This provides
quantification for grading vertebral deformities." Discovery also
features Hip Structure Analysis (HSA) software designed by The
Johns Hopkins University Applied Physics Laboratory (Baltimore, MD)
to examine the structural geometry of the hip with 2-dimensional
densitometry images. This software was developed to assess the
structural integrity of the bone, not just bone mineral
Hologic recently received U.S. Food and Drug Administration
clearance for use of the Discovery images as "a measure of the
possibility of coronary heart disease, stroke, and other forms of
cardiovascular disease" through the assessment of aortic
calcifications on the densitometry images (Figure 2). With this,
physicians can use the information already contained within the
scan to assess the patient's risk of a cardiovascular event, since
aortic calcification is a strong predictor of cardiovascular
"All of these advances are ways to make the DXA basic bone
density system a more useful tool in looking at overall patient
health," explained Jenkins. "You start out with a basic bone
density value, which is a good assessment of fracture risk. When
you add vertebral imaging, it becomes a better assessment of
fracture risk. Then, since hips are essentially a mechanical device
that hold the body up, with bone geometry, the clinician is better
able to predict potential bone failure. With the ability to assess
cardiovascular risk, there is yet another layer of value."
Looking to the future, Jenkins predicts that the next advance in
DXA technology will be 3-dimensional reconstruction of the hip with
bone densitometry images, similar to computed tomography
reconstructions. "By taking a limited data set and reconstructing a
3D image of the hip," he concluded, "we hope to take very accurate
geometric measurements of the hip and to better assess its