Epidemiology of Osteoporosis By : P.MOTTAGHI MD Associate Professor of Medicine – Rheumatology...
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Transcript of Epidemiology of Osteoporosis By : P.MOTTAGHI MD Associate Professor of Medicine – Rheumatology...
Epidemiology
of Osteoporosis
By : P.MOTTAGHI MD
Associate Professor of Medicine – Rheumatology Department
• Bone accretion occurs during adolescence, when there is a large
increment in bone mass.
• Peak bone density is normally achieved after puberty and into the
third decade of life.
• However, by age 22, most individuals have achieved their peak
bone mass.
• At menopause, an acceleration of bone loss usually occurs over
approximately 5 to 8 years, with an annual 2% to 3% loss of
trabecular bone and a 1% to 2% loss of cortical bone.
• Both men and women lose bone with age. Over a lifetime, women
lose approximately 50% of trabecular and 30% of cortical bone;
men generally lose two thirds of these amounts.
Genetics, gender, and racial differences
• There are few data on ratio or gender differences in age related bone
loss ,although limited evidence suggests that bone loss at the hip is
greater in women than in men.
• Lifestyle factors and level of economic development also contributes to
the geographic variability in facture risk.
• Peak bone mass determined largely by genetics .
• Genetic factors account for about 70 to 80% of interdividual
variation in peak bone mass in both gender.
• Environmental factors , especially diet and mechanical loading ,also
play a role in determining peak bone mass .
• There are few data on racial or gender differences in age- related bone
loss .
BONE REMODELING
Brief summery
animation
• Osteoporosis was previously thought to be a silent disease that
was part of the normal aging process.
• However, the advent of bone densitometry has made it possible
to accurately and reproducibly identify patients at risk for
osteoporosis so that prevention and treatment strategies can be
instituted to reduce fractures.
•
• Osteoporosis, the most common metabolic bone disease, affects 200 million
individuals worldwide.
• 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, especially of the hip, spine and wrist.
• Initial studies of the epidemiology of osteoporosis was based on bone mineral
content ,but no international agreement on the interpretation of the results
made. Some groups rely on age- and sex-specific ‘normal’ ranges; others
interpret their data in the light of the biomechanical concept of an absolute
fracture threshold.
• Therefore, the epidemiology of osteoporosis is still predominantly identical
with the epidemiology of its major consequence, i.e. certain types of bone
fractures claimed to be associated with osteoporosis
Epidemiology
• 40% of women over 50 have osteopenia
7% of women over 50 have osteoporosis
• Presence of osteoporosis carries 4-fold
increase in fracture rate
(over 50 years old)
• Among those who live to 90 years old, 1/3 of women and 1/6
of men will have sustained osteoporotic fracture
• After 50 years of age, there is an exponential rise in fractures, such
that 40% of women and 13% of men develop one or more
osteoporotic fractures in their lifetimes.
• In the United States alone, there are more than 1.5 million
osteoporotic fractures annually, including 250,000 hip, 250,000
wrist, and 500,000 vertebral fractures.
• Hip fractures are associated with a 12% to 24% mortality rate in
women and a 30% mortality rate in men within the first year of
fracture, and 50% of patients are unable to ambulate independently
and require long-term nursing home care.
• These numbers will continue to grow exponentially as the elderly
population of industrialized nations increases.
Clinical Crisis
• 25 million women with osteoporosis or osteopenia in US in
2003
• At 50 years, 10% population
• At 65 years, 20-25% population
• At 75 year, 40% population
• $13 billion for care of patients with osteoporotic spinal
fracture in 1997
Vaccaro 2003
Epidemiology of osteoprosis in IranEpidemiology of osteoprosis in Iran
Risk factors for osteoporosis
Female gender
Age (post-menopausal or > 70 years)
Asian or Caucasian
Smoking, alcohol consumption
Thin body shape
Inactivity/immobility
Diet low calcium, high protein, caffeine, sodium
Some drugs glucocorticoids, chemotherapy, etc.
Some systemic diseases gastrectomy, chronic liver or renal disease, etc.
Risk FactorsRisk Factors
Female GenderFemale Gender
– 3X more likely to have hip or vertebral fracture than 3X more likely to have hip or vertebral fracture than
menmen
– 6X more likely to have forearm fracture6X more likely to have forearm fracture
Caucasian RaceCaucasian Race
– Higher than African-American, Asian raceHigher than African-American, Asian race
SmokingSmoking
Low Body Weight (less than 58 kilos)Low Body Weight (less than 58 kilos)
Risk Factors (cont’d)Risk Factors (cont’d) Sedentary LifestyleSedentary Lifestyle
Excessive Alcohol IntakeExcessive Alcohol Intake
– Ample suggestion that moderate alcohol intake Ample suggestion that moderate alcohol intake
may be protectivemay be protective
– No clear thresholdNo clear threshold
Nursing Home ResidentsNursing Home Residents
– 10X more likely to experience hip fracture than 10X more likely to experience hip fracture than
age-matched non-residents age-matched non-residents
Predisposing Medical ConditionsPredisposing Medical Conditions
Estrogen DeficiencyEstrogen Deficiency
Inflammatory Bowel DiseaseInflammatory Bowel Disease
Type 2 Diabetes Mellitus Type 2 Diabetes Mellitus
Celiac diseaseCeliac disease
Cystic fibrosisCystic fibrosis
HyperthyroidismHyperthyroidism
HyperparathyroidismHyperparathyroidism
HypogonadismHypogonadism
Liver DiseaseLiver Disease
Corticosteroid useCorticosteroid use
Heparin useHeparin use
Cyclosporine useCyclosporine use
Depo-Provera useDepo-Provera use
Risk Factors (cont’d)Risk Factors (cont’d)
No clear increase in risk with carbonated beveragesNo clear increase in risk with carbonated beverages
Although unclear risk association with excessive Although unclear risk association with excessive caffeinecaffeine
Bone mineral density and fracture
• The relationship between BMD and osteoporosis can be
compared with that between blood pressure and stroke.
• Although low BMD is not a prerequisite for osteoporotic
fracture, the risk for fracture is elevated considerably in the
presence of low bone mass.
• Therefore, as with blood pressure, appropriate cut-off values can
be defined to direct intervention toward ‘‘at-risk’’ individuals.
• BMD taken at different sites can be used to predict the future
risk for fracture at the same, or other, sites
Bone Mineral Density (BMD) and fracture rate
Siris et al. Arch Intern Med. 2004; 164:1108-1112
BMD does not fully explain increased fracture risk in the elderly
Age-related changes in bone quality are not fully captured
by BMD
– Bone structure
– Material properties of bone
Increased risk of falls
BMD Does Not Fully Explain the Effect of Age on Fracture Risk
50 80Age
BMD
Fracture risk
Determinants of Bone quality (1) Bone Structure
Macroarchitecture
Microarchitecture
Hip axis length
Cross sectional diameter
TrabecularPerforation
Cortical Porosity
Morbidity
• Overall, a 50-year-old white woman in the United States has a 13%
chance of experiencing attributable functional decline after any
fracture.
• The degree of functional recovery after this injury is age dependent;
in the United States, 14% of patients in the 50- to 55-year age group
who sustained a hip fracture were discharged to nursing homes,
compared with 55% of those aged older than 90 years.
• Hip fracture also has a significant effect on mobility; 1 year after hip
fracture, 40% were unable to walk independently, 60% required
assistance with at least one essential activity of daily living (eg,
dressing, bathing), and 80%were unable to perform at least one
instrumental activity of daily living (eg, driving, shopping)
• The impact of a single vertebral fracture may be low;
however, multiple fractures cause progressive loss of height
and kyphosis and severe back pain in the acute stages. The
resultant loss of mobility can exacerbate underlying
osteoporosis, which leads to the increased risk for further
fractures.
• Although good functional recovery after distal forearm
fracture may be poor, reflecting complications (eg, reflex
sympathetic dystrophy, neuropathies, posttraumatic arthritis),
mortality after Colles’ fracture does not deviate from the
expected rate.
Clinical Features
Clinical manifestations
• Fracture
• Spine
• Hip
• wrist
Clinical manifestations
Kyphosis
Height loss
Symptoms
• Early
• Loss of bone mineral density
• Late • Spine (“Dowager Hump”) & Fx
• Hips Fx
• Colles’ (wrist) Fx
• Secondary Affects• Depression
• Pain
• Deformity
• Dependency
• Fear of falling
• Premature death
Fracture Incidence
Melton 1995
Hip Fracture
• Most commonly treated fracture with respect to osteoporosis
• Requires surgical intervention for future ambulation
• Risk of morbidity 5-20% increase
• The highest rates of hip fracture are seen in white populations that live
in northern Europe, where the age-adjusted 1-year cumulative
incidence in Norway in 1989 was 903/100,000 for women and
384/100,000 for men.
• The rates are intermediate in Asians, in China, and in Kuwait, and are
lowest in black populations.
• In Western populations, among individuals who are older than 50 years
of age, there is a female preponderance of hip fracture, with a
female/male incidence ratio of approximately 2:1.
Risk Factors for Hip Fracture Largely Independent of BMD
Previous fracture
Family history
Glucocorticoid therapy
Smoking
Alcohol intake
Rheumatoid arthritis
Seasonal Variations in Vitamin D and Hip Fracture (Paso et al, 2005, JBMR 19:752)
vertebral Fractures
• Thoracic
• Height loss (often of several inches) with multiple sites,
kyphosis, and secondary pain, discomfort related to altered
biomechanics of the back, restricted respiratory disease
• Lumbar
• Abdominal symptoms including distention, early satiety,
and constipation
• 60% of vertebral fractures remain undiagnosed during first
year of occurrence.
• Only about one third of all vertebral deformities that are
noted on radiographs come to medical attention, and less
than 10% necessitate admission to the hospital
Risk Factors for Vertebral Fracture
Age
Gender
Previous fracture
Low BMD
Premature menopause
Smoking
Use of a walking aid
• Recent data from the Epidemiology of Osteoporosis Study
yielded estimates of the prevalence of vertebral fractures to be
19% among women aged 75 to 79 years, 21.9% among
women aged 80 to 84 years, and 41.4% among those aged 85
years and older.
• Only one quarter of vertebral fractures result from falls. Most
are precipitated by routine daily activities (eg, bending or
lifting light objects),
Wrist fracture
• In white women, the incidence increases linearly between the
ages of 40 and 65 years, and then stabilizes.
• There is no apparent increase in the incidence of wrist fracture
with age in men.; in men, the incidence remains constant
between 20 and 80 years.
• United Kingdom showed that among women, the incidence of
distal radius fracture increased from a premenopausal baseline
of 10 per 10,000 population per year to a peak of 120 per
10,000 population per year over 85 years.
Other fractures
• The incidence of proximal humeral, pelvic, and proximal
tibial fractures also increase steeply with age, and are
greater in women than in men.
Osteoporotic fracture: Influence of Age and Gender
MenMen
35–39 85
Age group (years)
WomenWomen Hip
Vertebrae
Colles’4000
3000
2000
1000
20
35–39 85
Inci
den
ce/1
00,0
00 p
erso
n-y
ears
Survival Following Fracture >65
Years (GPRD) Van Staa et al, 2001, Bone 29:517
Femur/hip Vertebral
Observed Expected Observed Expected
Women
3 months 85.6% 97.7% 94.3% 98.4%
12 months 74.9% 91.1% 86.5% 93.6%
5 years 41.7% 60.9% 56.5% 69.6%
Men
3 months 77.7% 97.3% 87.8% 97.9%
12 months 63.3% 90.0% 74.3% 91.8%
5 years 32.2% 58.2% 42.1% 64.4%