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Osteoporosis
More
from the Osteoporosis Consensus
More
from the Osteoporosis Consensus
This is more information from the Consensus, they have written
such thorough information that we have to share it.
What is osteoporosis and what are
its consequences?
Osteoporosis is defined as a skeletal
disorder characterized by compromised bone strength predisposing to an
increased risk of fracture. Bone strength reflects the integration of
two main features: bone density and bone quality. Bone density is
expressed as grams of mineral per area or volume and in any given
individual is determined by peak bone mass and amount of bone loss. Bone
quality refers to architecture, turnover, damage accumulation (e.g.,
microfractures) and mineralization. A fracture occurs when a
failure-inducing force (e.g., trauma) is applied to osteoporotic bone.
Thus, osteoporosis is a significant risk factor for fracture, and a
distinction between risk factors that affect bone metabolism and risk
factors for fracture must be made.
It is important to acknowledge a common misperception that osteoporosis
is always the result of bone loss. Bone loss commonly occurs as men and
women age; however, an individual who does not reach optimal (i.e.,
peak) bone mass during childhood and adolescence may develop
osteoporosis without the occurrence of accelerated bone loss. Hence
sub-optimal bone growth in childhood and adolescence is as important as
bone loss to the development of osteoporosis.
Currently there is no accurate measure of overall bone strength. Bone
mineral density (BMD) is frequently used as a proxy measure and accounts
for approximately 70 percent of bone strength. The World Health
Organization (WHO) operationally defines osteoporosis as bone density
2.5 standard deviations below the mean for young white adult women. It
is not clear how to apply this diagnostic criterion to men, children,
and across ethnic groups. Because of the difficulty in accurate
measurement and standardization between instruments and sites,
controversy exists among experts regarding the continued use of this
diagnostic criterion.
Osteoporosis can be further characterized as either primary or
secondary. Primary osteoporosis can occur in both genders at all ages
but often follows menopause in women and occurs later in life in men. In
contrast, secondary osteoporosis is a result of medications, other
conditions, or diseases. Examples include glucocorticoid-induced
osteoporosis, hypogonadism, and celiac disease.
The consequences of osteoporosis include the financial, physical, and
psychosocial, which significantly affect the individual as well as the
family and community. An osteoporotic fracture is a tragic outcome of a
traumatic event in the presence of compromised bone strength, and its
incidence is increased by various other risk factors. Traumatic events
can range from high-impact falls to normal lifting and bending. The
incidence of fracture is high in individuals with osteoporosis and
increases with age. The probability that a 50-year-old will have a hip
fracture during his or her lifetime is 14 percent for a white female and
5 to 6 percent for a white male. The risk for African Americans is much
lower at 6 percent and 3 percent for 50-year-old women and men,
respectively. Osteoporotic fractures, particularly vertebral fractures,
can be associated with chronic disabling pain. Nearly one-third of
patients with hip fractures are discharged to nursing homes within the
year following a fracture. Notably, one in five patients is no longer
living 1 year after sustaining an osteoporotic hip fracture. Hip and
vertebral fractures are a problem for women in their late 70s and 80s,
wrist fractures are a problem in the late 50s to early 70s, and all
other fractures (e.g., pelvic and rib) are a problem throughout
postmenopausal years. The impact of osteoporosis on other body systems,
such as gastrointestinal, respiratory, genitourinary, and craniofacial,
is acknowledged, but reliable prevalence rates are unknown.
Hip fracture has a profound impact on quality of life, as evidenced by
findings that 80 percent of women older than 75 years preferred death to
a bad hip fracture resulting in nursing home placement. However, little
data exist on the relationship between fractures and psychological and
social well-being. Other quality-of-life issues include adverse effects
on physical health (impact of skeletal deformity) and financial
resources. An osteoporotic fracture is associated with increased
difficulty in activities of daily life, as only one-third of fracture
patients regain pre-fracture level of function and one-third require
nursing home placement. Fear, anxiety, and depression are frequently
reported in women with established osteoporosis and such consequences
are likely under-addressed when considering the overall impact of this
condition.
Direct financial expenditures for treatment of osteoporotic fracture are
estimated at $10 to $15 billion annually. A majority of these estimated
costs are due to in-patient care but do not include the costs of
treatment for individuals without a history of fractures, nor do they
include the indirect costs of lost wages or productivity of either the
individual or the caregiver. More needs to be learned about these
indirect costs, which are considerable. Consequently, these figures
significantly underestimate the true costs of osteoporosis.
How do risks vary among different segments of the population?
Gender/Ethnicity
The prevalence of osteoporosis, and incidence of fracture, vary by
gender and race/ethnicity. White postmenopausal women experience almost
three-quarters of hip fractures and have the highest age-adjusted
fracture incidence. Most of the information regarding diagnosis and
treatment is derived from research on this population. However, women of
other age, racial, and ethnic groups, and men and children, are also
affected. Much of the difference in fracture rates among these groups
appears to be explained by differences in peak bone mass and rate of
bone loss; however, differences in bone geometry, frequency of falls,
and prevalence of other risk factors appear to play a role as well.
Both men and women experience an age-related decline in BMD starting in
midlife. Women experience more rapid bone loss in the early years
following menopause, which places them at earlier risk for fractures. In
men, hypogonadism is also an important risk factor. Men and
perimenopausal women with osteoporosis more commonly have secondary
causes for the bone loss than do postmenopausal women.
African American women have higher bone mineral density than white
non-Hispanic women throughout life, and experience lower hip fracture
rates. Some Japenese women have lower peak BMD than white non-Hispanic
women, but have a lower hip fracture rate; the reasons for which are not
fully understood. Mexican American women have bone densities
intermediate between those of white non-Hispanic women and African
American women. Limited available information on Native American women
suggests they have lower BMD than white non-Hispanic women.
Risk Factors
Risks associated with low bone density are supported by good evidence,
including large prospective studies. Predictors of low bone mass include
female gender, increased age, estrogen deficiency, white race, low
weight and body mass index (BMI), family history of osteoporosis,
smoking, and history of prior fracture. Use of alcohol and
caffeine-containing beverages is inconsistently associated with
decreased bone mass. In contrast, some measures of physical function and
activity have been associated with increased bone mass, including grip
strength and current exercise. Levels of exercise in childhood and
adolescence have an inconsistent relationship to BMD later in life. Late
menarche, early menopause, and low endogenous estrogen levels are also
associated with low BMD in several studies.
Although low BMD has been established as an important predictor of
future fracture risk, the results of many studies indicate that clinical
risk factors related to risk of fall also serve as important predictors
of fracture. Fracture risk has been consistently associated with a
history of falls, low physical function such as slow gait speed and
decreased quadriceps strength, impaired cognition, impaired vision, and
the presence of environmental hazards (e.g., throw rugs). Increased risk
of a fracture with a fall includes a fall to the side and attributes of
bone geometry, such as tallness, hip axis, and femur length. Some risks
for fracture, such as age, a low BMI, and low levels of physical
activity, probably affect fracture incidence through their effects on
both bone density and propensity to fall and inability to absorb impact.
Results of studies of persons with osteoporotic fractures have led to
the development of models of risk prediction, which incorporate clinical
risk factors along with BMD measurements. Results from the Study of
Osteoporotic Fractures (SOF), a large longitudinal study of
postmenopausal, white non-Hispanic women, suggest that clinical risk
factors can contribute greatly to fracture risk assessment. In this
study, 14 clinical risk factors predictive of fracture were identified.
The presence of five or more of these factors increased the rate of hip
fracture for women in the highest tertile of BMD from 1.1 per 1,000
woman-years to 9.9 per 1,000 woman-years. Women in the lowest tertile of
BMD with no other risk factors had a hip fracture rate of 2.6 per 1,000
woman-years as compared with 27.3 per 1,000 woman-years with five or
more risk factors present. A second model, derived from the Rotterdam
study, predicted hip fractures using a smaller number of variables,
including gender, age, height, weight, use of a walking aid, and current
smoking. However, these models have not been validated in a population
different from that in which they were derived.
Secondary Osteoporosis
A large number of medical disorders are associated with osteoporosis and
increased fracture risk. These can be organized into several categories:
genetic disorders, hypogonadal states, endocrine disorders,
gastrointestinal diseases, hematologic disorders, connective tissue
disease, nutritional deficiencies, drugs, and a variety of other common
serious chronic systemic disorders, such as congestive heart failure,
end-stage renal disease, and alcoholism.
The distribution of the most common causes appears to differ by
demographic group. Among men, 30 to 60 percent of osteoporosis is
associated with secondary causes; with hypogonadism, glucocorticoids,
and alcoholism the most common. In perimenopausal women, more than 50
percent is associated with secondary causes, and the most common causes
are hypoestrogenemia, glucocorticoids, thyroid hormone excess, and
anticonvulsant therapy. In postmenopausal women, the prevalence of
secondary conditions is thought to be much lower, but the actual
proportion is not known. In one study, hypercalciuria,
hyperparathyroidism, and malabsorption were identified in a group of
white postmenopausal osteoporotic women who had no history of conditions
that cause bone loss. These data suggest that additional testing of
white postmenopausal women with osteoporosis may be indicated, but an
appropriate or cost-effective evaluation strategy has not been
determined.
Glucocorticoid use is the most common form of drug-related osteoporosis,
and its long-term administration for disorders such as rheumatoid
arthritis and chronic obstructive pulmonary disease is associated with a
high rate of fracture. For example, in one study, a group of patients
treated with 10 mg of prednisone for 20 weeks experienced an 8 percent
loss of BMD in the spine. Some experts suggest that any patient who
receives orally administered glucocorticoids (such as Prednisone) in a
dose of 5 mg or more for longer than 2 months is at high risk for
excessive bone loss.
People who have undergone organ transplant are at high risk for
osteoporosis due to a variety of factors, including pretransplant organ
failure and use of glucocorticoids after transplantation.
Hyperthyroidism is a well-described risk factor for osteoporosis. In
addition, some studies have suggested that women taking thyroid
replacement may also be at increased risk for excess bone loss,
suggesting that careful regulation of thyroid replacement is important.
Children and Adolescents
Several groups of children and adolescents may be at risk for
compromised bone health. Premature and low birth weight infants have
lower-than-expected bone mass in the first few months of life, but the
long-term implications are unknown.
Glucocorticoids are now commonly used for the treatment of a variety of
common childhood inflammatory diseases, and the bone effects of this
treatment need to be considered when steroid use is required
chronically. The long-term effects on bone health of intermittent
courses of systemic steroids or the chronic use of inhaled steroids, as
are often used in asthma, are not well described.
Cystic fibrosis, celiac disease, and inflammatory bowel disease are
examples of conditions associated with malabsorption and resultant
osteopenia in some individuals. The osteoporosis of cystic fibrosis is
also related to the frequent need for corticosteroids as well as to
other undefined factors.
Hypogonadal states, characterized clinically by delayed menarche,
oligomenorrhea, or amenorrhea, are relatively common in adolescent girls
and young women. Settings in which these occur include strenuous
athletic training, emotional stress, and low body weight. Failure to
achieve peak bone mass, bone loss, and increased fracture rates have
been shown in this group. Anorexia nervosa deserves special mention.
Although hypogonadism is an important feature of the clinical picture,
the profound undernutrition and nutrition-related factors are also
critical. This latter point is evidenced, in part, by the failure of
estrogen replacement to correct the bone loss.
Residents of Long-Term Care Facilities
Residents of nursing homes and other long-term care facilities are at
particularly high risk of fracture. Most have low BMD and a high
prevalence of other risk factors for fracture, including advanced age,
poor physical function, low muscle strength, decreased cognition and
high rates of dementia, poor nutrition, and, often, use of multiple
medications.
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