Osteoporosis Flashcards
What is osteoporosis?
skeletal disorder characterized by low bone mass and deterioration of bone tissue leading to increased bone fragility and risk of fracture
* osteoporotic bone is thinner, more porous, and weaker than healthy bone
What is diagnosis of osteoporosis?
Bone density is obtained through DXA (dual energy x-ray absorptiometry)
* Postmenopausal women
What is a T-score?
calculated by comparing the result to the distribution of bone density in healthy young women
What does a T-score between -1 and -2.5 indicates?
osteopenia
* stage before osteoporosis
What does a T-score greater or equal to -2.5 indicates?
osteoporosis
What is osteoporosis prevalence in Canada?
- 2.5 million Canadians are affected by osteoporosis (about 80% women)
- 14.7% of women and 2.5% of men 50-70 yrs
- 31.3% of women and 6.4% of men over 70
How does osteoporosis increased fracture risk in canada?
- In Canada, osteoporosis causes over80% of all fractures in people 50+
- An estimated 1 in 3 women and 1 in 5 men in a group of 50+ will experience an osteoporotic fracture
- Common fracture sites include hip, spine & wrist
- 22% of women and 33% of men who suffer a hip fracture will die within the following year
What are the modifiable risk factors for osteoporosis?
- Smoking
- Low body weight
- Low calcium intake
- Low sun exposure
- Alcohol abuse
- History amenorrhea
- Estrogen deficiency (females)
- Testosterone deficiency (males)
- Repeated falls
- Sedentary lifestyle
What are non-modifiable risk factors for osteoporosis?
- Older age
- Caucasian or Asian
- History of fracture
- Family history osteoporosis
- Female
What are the stages of bone development?
Begins in utero and continues to early adulthood
* Bone growth
* Bone modeling
Occurs primarily in adulthood
* Bone remodeling
What is bone growth?
Increased size
What is bone modeling?
Determines bone shape
What is bone remodeling?
- Maintain integrity of bone
- Replaces old bone with new
What are the two types of bone cells in bone remodeling?
Osteoclast
Osteoblast
What is osteoclast?
type of bone cell that
resorbs/dissolves bone using acid & enzymes
What is osteoblast?
bone building cell
What is the process of bone remodeling?
1) Osteoclasts break down bone by resorption
- Release calcium (& other minerals) into blood
- Repair damaged bone
- Strengthen bone
2) Osteoblasts rebuild bone
How does bone develop through the lifespan?
- Childhood/adolescence:
- Bone formation > bone resorption → bone
growth - Early to middle adulthood
- Bone formation = bone resorption
- Later adulthood and older age (~40+):
- Bone formation < bone resorption → bone loss
Bone density decreases as we age. The rate of bone loss is greatest:
A) Right after peak bone mass is
reached, ~30 yrs of age
B) At the onset of menopause
C) After age 70
B) At the onset of menopause
Why is peak bone density important?
- How much bone you have accumulated at peak bone mass determines how much you can remove before crossing the
threshold for osteoporosis - Bone health is important across the lifespan
What is prevention of osteoporosis?
depends on optimizing peak bone mass, minimizing exposures that lead to bone loss, and optimizing nutritional exposures for bone
maintenance throughout life
Which bone has a faster turnover rate?
Trabecular bone has faster turnover rate than cortical bone
- Higher rate of fracture in regions with greater proportion of trabecular bone
- Hip, spine, wrist
What is cortical bone?
outer part of all skeletal structures; is dense and compact with a slow turnover rate and is highly resistant to bending and torsion.
What is trabecular bone?
found inside of long bones, vertebrae, pelvis, and other large flat bones; is less dense than cortical bone and has a higher turnover rate.
