OsteoporosisOsteoporosis

UBC Internal Medicine Program

Dr. Mark FokDr. Maria Ashley

DefinitionDefinitionOsteoporosis and osteopenia are skeletal

disorders characterized by low bone mass and microarchitectural fragility.

Bone remodellingBone remodelling

IncidenceIncidence

1.4 million Canadians affected1 in 4 women over age 50 and 1 in 8 men

over age 50Estimated cost of $1.9 billion to treat

osteoporosis and fractures in Canada70% of hip fractures are osteoporosis

related www.osteoporosis.ca

What else do you want to know?What else do you want to know?

Major Risk Factors for OsteoporosisAge >65Vertebral compression #Family hx of osteoporotic #>5 months glucocorticoid txMalabsorbtion syndrome1 hyperparathyroidismOsteopenia on XRHypogonadismEarly menopause (before 45)

Minor Risk Factors

◦Rheumatoid arthritis◦Hyperthyroidism◦Prolonged anticonvulsants◦Prolonged heparin use◦Body weight <57kg◦Low calcium intake◦Excess caffeine (>4 cups/day)◦Excess alcohol (>2 drinks/day)◦Smoker

Risk for FractureRisk for FractureLow Bone Mineral DensityPrior fragility fractureLong term (>3 months) glucocorticoidsIncreasing ageFamily history of osteoporotic fracture

Signs and Symptoms of OsteoporosisSigns and Symptoms of Osteoporosis

Self reported height loss >3cmWeight <51kgKyphosis - Self reported hump backGrip strength <40lbTooth count <20

Diagnosis of OsteoporosisDiagnosis of Osteoporosis

Assessment bone microarchitecture – bone biopsy

Clinical – fracture in the right context

Gold standard…

Bone Mineral Density AssessmentBone 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 1991Marshall D et al. BMJ 1996

DXADXA

Xray tube generates photon beams at two energy levels

Difference in attenuation BMD determination

For comparison, must use same machine

Interpreting a DXA Scan ?Interpreting a DXA Scan ?

Interpreting the DXAInterpreting the DXA

T-score: ◦Standard deviation between a pt’s BMD and

that of a young adult reference population

Z-score: ◦Standard deviation between a pt’s BMD and

that of an age matched population

Interpreting the DXA – WHO criteriaInterpreting the DXA – WHO criteria

Normal - 1 < T score

Low Bone Mass (osteopenia)

- 2. 5 < T score < - 1

Osteoporosis T score < - 2.5

Severe osteoporosis T score < - 2.5 + fragility fracture

DXA scan hip / L-spineDXA scan hip / L-spine

Treatment of OsteoporosisTreatment of Osteoporosis

Non-drug options

Drug options

Weight bearing exercisesWeight bearing exercises

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

Calcium rich foods

Over the counter vitaminsOver the counter vitamins

1200-1500 mg elemental calcium per day

800 IU vitamin D per day

Drugs – “Bisphosphonates”Drugs – “Bisphosphonates”

Alendronate

Risedronate

Etidronate

DosingDosing

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

Risedronate Risedronate

Similar efficacy

Comparable to Alendronate

Rosen et al. J Bone Miner. Res. 2005

““Selective Estrogen Selective Estrogen

Receptor Modulators”Receptor Modulators”

Raloxifene

Tamoxifen Bind with high affinity to Estrogen Receptor and

possess tissue selective agonist / antagonist properties bone specific “estrogen like” action

Bone Forming (Anabolic)Bone Forming (Anabolic) MedicationsMedications

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.

Estrogen therapyEstrogen 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

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 Women:10.Did you undergo menopause before age 45? 11.Have your periods stopped for several months or more (other than for pregnancy or menopause)?

For Men:12.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.

Thank youThank you