Osteoporosis and Bone Health Flashcards Preview

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Flashcards in Osteoporosis and Bone Health Deck (10)
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Is bone a greater proportion of cortical or trabecular bone?

Cortical (80%)
Trabecular (20%)


Approximately what percentage of bone is remodelled each year?



Where does bone remodelling occur?

Bone remodelling units
At the beginning the cycle, osteoclasts appear on a previously inactive surface and begin to resorb the bone
Osteoclasts are then replaced by osteoblasts that fill the cavity by putting down osteoid that is mineralised to form new bone
After a normal bone remodelling cycle the resorption cavity is completely refilled with new bone
However, in osteoporosis, there is a relative or absolute increase in resorption over formation that leads to increased bone loss


At which age is bone mass at its peak?

Bone mass peaks at age 30
Bone loss starts around age 40


Deficiency of what is the major determinant of bone loss in women after menopause?

In women, oestrogen deficiency is the major determinant of bone loss after the menopause


Armatase inhibitors and bone mass

Armatase inhibitors stop production of oestrogen in post menopausal women, they are used in breast cancer. They can lead to bone loss.
So can glucocorticoids


Risk factors for fracture

Previous fragility fractures
Current use or frequent past use of oral glucocorticoids
History of falls
Family history of hip fracture
Other secondary causes of osteoporosis
Low BM (10 cigarettes per day)
Alcohol intake >4 units per day


Family history of which type of fracture is a risk factor for fractures?

Hip fracture


Previous fractures as prediction of future fracture (colles, hip and spine)

Colles fractures DOUBLES risk of hip fracture
Fracturing one side of hip increases risk of fracturing other side
Any previous fractures increase risk of spine fracture independent of bone density


Corticosteroids and bone

Direct: Reduction of osteoblast activity and lifespan
Suppression of replication of osteoblast precursors
Reduction in calcium absorption

Indirect: Inhibition of gonadal and adrenal steroid production