Osteoporosis Flashcards
(26 cards)
What is osteoporosis and how does it affect the skeleton?
Osteoporosis is a skeletal disorder characterized by low bone mass and deterioration of bone tissue, which leads to increased bone fragility and a higher risk of fractures. Osteoporotic bone is thinner, more porous, and weaker than healthy bone.
How is osteoporosis diagnosed?
It is diagnosed using DXA (dual-energy X-ray absorptiometry) to measure bone mineral density (BMD). A T-score is calculated by comparing BMD to that of a healthy young adult.
T-score -1 to -2.5 = osteopenia
T-score < -2.5 = osteoporosis
What are the most common sites for osteoporotic fractures?
Hip, spine, and wrist—areas with high bone turnover and less efficient bone remodeling with age.
Why are women more likely than men to develop osteoporosis?
Due to menopause, which causes a drop in estrogen—a hormone important for bone maintenance. Women also tend to have lower bone mass to begin with.
What percentage of women and men over 70 are affected by osteoporosis in Canada?
31% of women and 6% of men over 70 are affected.
What are the 7 modifiable risk factors for osteoporosis?
Smoking, low body weight, low calcium and vitamin D intake, alcohol abuse, estrogen/testosterone deficiency, sedentary lifestyle, and frequent falls.
What are the 5 non-modifiable risk factors for osteoporosis?
Older age, female gender, family history of osteoporosis, prior fracture, and ethnicity (higher risk in Caucasian and Asian individuals).
What is the difference between bone growth, modeling, and remodeling?
Growth: increase in bone size
Modeling: shaping of bone
Remodeling: replacement of old bone with new bone (maintains bone integrity)
What is the function of osteoblasts?
Osteoblasts are bone-forming cells that build bone by producing collagen and aiding in mineral deposition.
. What is the role of osteoclasts?
Osteoclasts break down bone tissue by secreting acid and enzymes, releasing calcium and minerals into the blood.
What is bone remodeling and why is it important?
Bone remodeling is the continual process of resorption and formation that repairs bone microdamage, maintains mineral homeostasis, and strengthens bone.
. What is cortical bone and where is it found?
Cortical bone is dense and compact bone found on the outer layer of bones. It has slow turnover and is resistant to bending and torsion.
. What is trabecular bone and why is it more fracture-prone?
Trabecular bone is spongy and found in hips, vertebrae, and wrists. It has a higher turnover rate and is more sensitive to hormonal and nutritional changes.
When is peak bone mass typically reached, and why is it important?
Peak bone mass is reached between ages 20–30. A higher peak means more bone can be lost before reaching the threshold for osteoporosis.
What life stages show the most rapid bone loss?
During the 3–5 years around menopause due to hormonal changes, especially a drop in estrogen.
What nutrients are components of bone and support bone structure?
Calcium, phosphorus, magnesium, and trace minerals make up hydroxyapatite, the mineral matrix of bone.
What nutrients help regulate bone formation and resorption?
Vitamin D, vitamin K, magnesium, and potassium help maintain calcium homeostasis and support bone remodeling.
How does vitamin D support bone health?
It enhances calcium absorption in the gut, supports bone mineralization, and is activated in the kidneys and liver with the help of parathyroid hormone.
How does calcium regulation occur when blood levels are low?
Parathyroid hormone (PTH) increases, promoting calcium resorption from bone, calcium reabsorption in kidneys, and activating vitamin D to increase absorption in the gut.
Why should calcium intake be spaced throughout the day?
Because calcium absorption is less efficient when consumed in large doses at once. Multiple smaller doses are better absorbed.
What role does vitamin K play in bone health?
It is required as a cofactor for the activation of proteins like osteocalcin that are involved in bone formation.
How does high protein intake affect bone health?
While essential for bone building, excessive protein can increase calcium loss in urine. This is only problematic if calcium intake is also low.
How do sodium and phosphorus affect bone health?
Excess sodium increases calcium excretion, and high phosphorus (especially from cola) can promote bone resorption through PTH activation.
How can caffeine and alcohol negatively affect bone health?
Caffeine increases urinary calcium excretion, but can be offset by adequate calcium intake.
Alcohol (in high amounts) decreases bone density and interferes with calcium and vitamin D metabolism.
