Bone Health - Lecture

Question 1

Two types of bone

Answer 1

Cortical (compact)
Trabecular (spongey, cancellous)

Question 2

What is within bone structure?

Answer 2

Question 3

Function of bone

Answer 3

Structure:
* Shape of body
* Protect organs
* Locomotion
* Respiration

Metabolic:
* Calcium reservoir
* Phosphorus
* Carbonate
* Buffer H+ changes

Haemopoesis
* RBC
* WBC
* Platelets

Question 4

Deteminants of bone health

Answer 4

• Genetics
• Calcium
• Vitamin D
• Physical activity
• Healthy weight

Question 5

Negative factors on bone health

Answer 5

• Smoking
• Alcohol
• Hypogonadism
• Malnutrition
• Drugs eg steroids, PPIs, statins, antiretrovirals, antifungals, anticonvulsants

Question 6

Daily requirment of calcium

Answer 6

700mg per day for adults

Question 7

What is calcium levels determined by?

Answer 7

• Dietary intae
• Intestinal absorption
• Bone resorption
• Urinary excretion

Question 8

Foods high in calcium

Answer 8

• Milk/dairy products
• Tofu
• Nuts
• Fish

Question 9

Vitamin D activation pathway

Answer 9

Question 10

Main source of vitamin D

Answer 10

Sunlight
Then synthesised from 7-dehydroxycholesterol in body

Question 11

What is Vitamin D2 and D3

Answer 11

D2 - ergocalciferol
D3 - cholecalciferol

Question 12

Sources of dietary vitamin D

Answer 12

• Oily fish
• Red meat
• Liver
• Egg yolks
• Fortified cereals etc

Question 13

Levels of 25 (OH) Vitamin D (Calcifediol) which are adequeate

Answer 13

• Less than 25nmol/L = deficient
• 25-50 = inadequate
• More than 50 = sufficient

Question 14

RF for vitamin D deficiency

Answer 14

• 65 and older
• Low/no exposure to sun
• Malabsorption
• Severe liver or end stage CKD
• Medications eg laxatives, steroids
• Pregnancy and breastfeeding
• Obesity

Question 15

Preventative measures for Vitamin D deficiency

Answer 15

• Safe sun exposure information
• Good diet sources of Vitamin D
• 400 IU of Vitamin D daily all year round for those with deficiency
• Others can have 400 IU just in autumn and winter

Question 16

Complications of Vitamin D deficiency

Answer 16

• Rickets - children, Osteomalacia - adults
• Osteoporosis
• Fragility fractures

Question 17

Exercise and bone health

Answer 17

• Need weight bearing exercise for bone health
• Over 65s need 150 mins per week of moderate exercise
• Can inc dancing, carrying groceries, up and down stairs, heavy gardening, yoga etc

Question 18

What is peak bone mass?

Answer 18

• Max bone mass achieved during life
• Usually third decade
• Time to attain depends on genetics, hormones and environment

Question 19

What is osteoporosis?

Answer 19

• Low bone mass
• Microarchitectural disruption
• Increased fragility

Question 20

How is diagnosis of OP made?

Answer 20

• Fragility fracture - eg of spine, hip, wrist, humerus, pelvis, ribs
• OR T score -2.5 or less standard deviations at any site

Question 21

How is T score calculated?

Answer 21

Do DEXA scan - dual energy x-ray absorbtiometry
This calculates bone mineral density
This is compared to bone density average of healthy young adult aged 30 of same sex
Standard deviation is calculated

Question 22

T score value cut offs

Answer 22

-1 –> -2.4 is osteopenia
-2.5 or less = osteoporosis

Question 23

When is DEXA scan not used?

Answer 23

• Pregnancy
• Implants, hardware devices in area of measurement - some reports are autogenerated, be careful with this as may be reading hip replacement density rather than bone etc
• Recently administered contrast

Question 24

What is a fragility fracture?

Answer 24

Fracture that results from minor trauma or spontaneously eg falling from standing height

Question 25

Who should be risk assessed for osteoporosis?

Answer 25

• Women over 65
• Men over 75

Or under these ages if:
* Previous fragility fracture
* Falls history
* Family history of hip fracture
* Rheumatoid arthirits
* Alcohol more than 3 units per day

Question 26

FRAX score domains

Answer 26

• Age
• Height
• Weight
• Previous fragility fracture
• Parental hip fracture
• Current smoker?
• Glucocorticoid use
• RA
• Secondary OP
• Alcohol 3 or more units daily
• Femoral neck bone density - don’t have to use

Question 27

What is then done following calculation of FRAX?

Answer 27

• Use FRAX to see what the 10yr risk of makor osteoporitic fracture is
• Then use NOGG (national OP guideline group) graph to see whether low, intermediate, high or very high risk (green, amber, red, dark red)

Question 28

NOGG algorthim treatment

Answer 28

• Green Low risk - offer lifestyle advice
• Amber Intermediate risk - check BMD and recalculate
• Red High risk - treat and measure BMD
• Dark red very high risk - treat and consider specialist referral to rheum (paraenteral treatment maybe considered by them)

Question 29

Treatment for OP

Answer 29

• Check calcium and vitamin D are adequate
• Bisphosphonates
• SERMs (selective oestrogen receptor modulators)
• Parathyroid hormone (teriparatide)
• Denosumab, Romosozumab - Biologics

Question 30

Guidance for taking bisphosphonates

Answer 30

• Sit up for 45 minutes after taking - can cause oesophagitis
• Take on empty stomach - for absorption
• Do not eat and drink for 30mins-2hrs after taking

Question 31

Examples of bisphosphonates

Answer 31

• Alendronic acid
• Ibandronic
• Risedronate
• Zoledronic acid (given once yearly IV infusion)

Come in tablet, liquid and injection
Takes 6-12 months to see effects
May need to take for 5+ yrs

Question 32

Bisphosphonates side effects

Answer 32

• Oesophagitis
• Swallowing problems
• Stomach pain
• Osteonecrosis of jaw - esp occurs if existing dental problems

Question 33

When is Denosumab given?

Answer 33

If bisphosphonates not seem to work/contraindicated

Question 34

How is Denosumab taken?

Answer 34

• SC injections every 6 months
• Take for 5-10 yrs

Question 35

Side effects of Denosumab

Answer 35

• Atypical fractures
• Hypocalcaemia
• Infection - immunosupression?
• Osteonecrosis of jaw

Question 36

Z score Vs T score

Answer 36

Z score - compares to others same age and gender
T score - compares to that of 30yr old