Osteoporosis

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Osteoporosis

• UBC Internal Medicine Program
• Dr. Mark Fok
• Dr. Maria Ashley

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Definition

• Osteoporosis and osteopenia are skeletal
  disorders characterized by low bone mass and
  microarchitectural fragility.

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Bone remodelling
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Incidence

• 1.4 million Canadians affected
• 1 in 4 women over age 50 and 1 in 8 men over age
  50
• Estimated cost of 1.9 billion to treat
  osteoporosis and fractures in Canada
• 70 of hip fractures are osteoporosis related
• www.osteoporosis.ca

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What else do you want to know?

• Major Risk Factors for Osteoporosis
• Age gt65
• Vertebral compression
• Family hx of osteoporotic
• gt5 months glucocorticoid tx
• Malabsorbtion syndrome
• 1 hyperparathyroidism
• Osteopenia on XR
• Hypogonadism
• Early menopause (before 45)

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• Minor Risk Factors
• Rheumatoid arthritis
• Hyperthyroidism
• Prolonged anticonvulsants
• Prolonged heparin use
• Body weight lt57kg
• Low calcium intake
• Excess caffeine (gt4 cups/day)
• Excess alcohol (gt2 drinks/day)
• Smoker

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Risk for Fracture

• Low Bone Mineral Density
• Prior fragility fracture
• Long term (gt3 months) glucocorticoids
• Increasing age
• Family history of osteoporotic fracture

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Signs and Symptoms of Osteoporosis

• Self reported height loss gt3cm
• Weight lt51kg
• Kyphosis - Self reported hump back
• Grip strength lt40lb
• Tooth count lt20

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Diagnosis of Osteoporosis

• Assessment bone microarchitecture bone biopsy
• Clinical fracture in the right context
• Gold standard

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Bone Mineral Density Assessment

• Dual-Energy Xray Absorptiometry (DXA)
• Strong correlation between mechanical bone
  strength DXA measurement of BMD
• Strong relationship between fracture risk and BMD
  measurement

Lotz JC et al. J Biomech Eng 1991 Marshall D et
al. BMJ 1996
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DXA

• Xray tube generates photon beams at two energy
  levels
• Difference in attenuation ? BMD determination
• For comparison, must use same machine

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Interpreting a DXA Scan ?

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Interpreting the DXA

• T-score
• Standard deviation between a pts BMD and that of
  a young adult reference population
• Z-score
• Standard deviation between a pts BMD and that of
  an age matched population

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Interpreting the DXA WHO criteria
Normal - 1 lt T score
Low Bone Mass (osteopenia) - 2. 5 lt T score lt - 1
Osteoporosis T score lt - 2.5
Severe osteoporosis T score lt - 2.5 fragility fracture
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DXA scan hip / L-spine
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Treatment of Osteoporosis

• Non-drug options
• Drug options

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Weight bearing exercises
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• Exercises that utilize your own body weight
  include activities like these, but also include
  simple activities like walking.

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Calcium rich foods
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Over the counter vitamins

• 1200-1500 mg elemental calcium per day
• 800 IU vitamin D per day

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Drugs Bisphosphonates

• Alendronate
• Risedronate
• Etidronate

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Dosing

• Once weekly dosing (70 mg q week) as effective as
  daily dosing of alendronate with similar side
  effect profile

Rizzoli et al. J Bone Miner Res 2002
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Risedronate

• Similar efficacy
• Comparable to Alendronate

Rosen et al. J Bone Miner. Res. 2005
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Selective Estrogen Receptor Modulators

• Raloxifene
• Tamoxifen
• Bind with high affinity to Estrogen Receptor and
  possess tissue selective agonist / antagonist
  properties ? bone specific estrogen like action

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Bone Forming (Anabolic) Medications

• Parathyroid Hormone Teriparatide (brand name -
  Forteo).
• Teriparatide, a type of parathyroid hormone, is
  approved for the treatment of osteoporosis in
  postmenopausal women and in men who have very low
  BMD or are at high risk for a fracture.

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Estrogen therapy

• Fallen out of favor for treatment of osteoporosis
  since WHI study
• Increased risk of CHD, VT, breast CA
• Should not be used first line, except for in
  women using it for other indications

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• Quick quiz 1.Are you over 65? 2.Has either of
  your parents broken a bone after a minor bump or
  fall? 3.Have you broken a bone after a minor
  bump or fall? 4.Have you taken glucocorticoid
  pills (cortisone, prednisone, etc.) for more than
  three months? 5.Have you lost more than 4 cm
  (about 1 1/2 inches) in height since age 25 (or 6
  cm if you are over 60)? 6.Do you have a tendency
  to fall? 7.Do you have primary
  hyperparathyroidism? 8.Do you have a medical
  condition (such as celiac disease or Crohn's
  disease) that inhibits absorption of nutrients?
  9.Has a recent x-ray suggested you have low bone
  density (osteopenia)?
• For Women10.Did you undergo menopause before age
  45? 11.Have your periods stopped for several
  months or more (other than for pregnancy or
  menopause)?
• For Men12.Have you ever suffered from impotence,
  lack of libido or other symptoms related to low
  levels of testosterone?
• If you're over 50 and have answered yes to any of
  these questions, Osteoporosis Canada recommends
  that you talk to your doctor about having a bone
  mineral density (BMD) test.

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Thank you