Bone health

Question 1

What is bone mineral content and bone mineral density?

Answer 1

• BMC: bone mineral content- mass expressed as absolute value (g)
• BMD: bone mineral density- mass expressed as mass per unit area or volume

Question 2

What age does bone mass peak?

Answer 2

30

Question 3

When is the maximum bone mineral density attained?

Answer 3

Adolescence

Question 4

What do osteoblasts and osteoclasts do?

Answer 4

-B- building (osteoblasts)

-C- catabolising (osteocytes)

Question 5

What is bone remodelling?

Answer 5

continuous cycle of replacement of old bone tissue with new bone tissue

Question 6

What is the role of vitamin D in bone remodelling?

Answer 6

Vitamin D maintains calcium and phosphate homeostasis by a negative feedback loop with PTH, aids calcium and phosphate absorption and triggers calcium mobilisation from bone when blood calcium is low

Question 7

What are signs of a vitamin D deficiency?

Answer 7

Often see higher PTH level (secondary hyperparathyroidism)
Under-mineralized or under calcified bone matrix
Hypocalcaemia- muscle cramps and twitching

Question 8

What are the consequences of vitamin D deficiency?

Answer 8

Rickets and osteomalacia

Question 9

What is osteomalacia?

Answer 9

Impaired bone remodelling- not enough minerals coming in to repair rigidity of the bone in final process of modelling due to lack of vitamin D
Pseudofractures
‘‘Softening of the bones’’

Question 10

What is rickets?

Answer 10

Disorder of the growth plates
Impaired bone mineralization and long bone growth
Treated with vitamin D and calcium intake or supplements combined
Can be hereditary or non hereditary

Question 11

What are the most common causes of rickets?

Answer 11

Vitamin D or calcium deficiency

Question 12

What is osteoporosis?

Answer 12

Often referred to as a silent disease
Multifactorial skeletal disease
Low bone mass and microartchitectural deterioration

Question 13

How is osteoporosis diagnosed?

Answer 13

Low bone mineral density or fragility fracture

Question 14

What is the appearance of osteoporosis?

Answer 14

gaps within bone tissue- honeycomb pattern with big holes

Question 15

What are the modifiable, non modifiable and other risk factors for osteoporosis?

Answer 15

-Non-modifiable: being female, age, family history, white or asian, early menopause
-Modifiable: diet, excess alcohol, cigarette smoking, sedentary lifestyle
-Other: anorexia, oophorectomy, steroids, low testosterone

Question 16

What is osteopenia?

Answer 16

At risk of osteoporosis but not progressed enough

Question 17

What is a DEXA scan?

Answer 17

The new gold standard of bone mineral measuring, X-ray beams at different energies, bone and soft tissue calculated by attenuation of x-ray beams passing through the body

Question 18

What are the negatives of DEXA scan?

Answer 18

Some radiation exposure and difficult to make comparisons in growing children or children with linear growth faltering.
Children may be moving too much

Question 19

What did the BONUSkids study look at?

Answer 19

-Bone and muscle mass in kids
-have compared children in the UK and Bangladesh
-Looking at how different levels of vitamin D supplementation affects childs bone and muscle development

Question 20

What is the FRAX tool?

Answer 20

Simiilar to QRISK tool, assesses risk of fracture in the next 10 years

Question 21

What are the treatment options of osteoporosis?

Answer 21

Anti-catabolic agents, anabolic agents

Question 22

What is the dominant mineral in hydroxyapatite?

Answer 22

Calcium

Question 23

What is the VITamin D and omegA-3 trial? (VITAL)

Answer 23

RCT in US- supplemented high dose vit D vs placebo, found no effect on fracture prevention. Findings not generalisable to populations at risk of calcium/vit D deficiency as there was already a high baseline vit D status. Controversy around the trial

Question 24

When does dietary protein have a protective effect on bone mass?

Answer 24

If calcium and vitamin D is adequate

Question 25

What effect is alcohol and salt thought to have on bones?

Answer 25

-non-linear positive relationship of alcohol with fracture risk
-high salt intake suggested to ↓ bone mass as excess sodium ↑ calciuria but trial evidence is limited

Question 26

What may phytoestrogens be good for in post-menopausal women?

Answer 26

Some evidence for protective effects on prevention of bone loss but inconsistent results