Mar 28 Bone Health - Osteoporosis Flashcards
Bone composition (3 things)
– 50% mineral crystals (i.e. calcium
phosphate)
– 50% protein (collagen)
– Trabecular (quicker turnover aka breaks down and rebuilds more quickly) and
cortical
Bone is alive:
2 ways bones heal themselves:
Continually broken down and reformed ->(re)modeling cycle
Bone modeling happens mostly during childhood and adolescence — it’s how bones grow and become stronger as kids develop. This is called pediatric bone accrual (building new bone mass).
Bone remodeling is a lifelong process where old or damaged bone is broken down and replaced with new bone. In adulthood, this helps maintain bone strength and repair minor damage.
In a constant state of turnover (resorption and formation): (5 things)
- Osteoblasts – bone forming/building cells
- Osteoclasts – bone resorbing cells
- Remodeling cycle starts with resorption
- Balance between resorption and formation = bone mass
- Issue when these processes are “uncoupled”
Bone Mass Across the Lifespan: (2 things)
Lifestyle practices when young affect peak bone mass development. Diet and exercise influence 20-40% of adult peak bone mass.
Osteoporosis Canada says:
“pediatric disease with geriatric consequences”
What is Osteoporosis?
Osteoporosis is a _____ characterised by:
– Compromised bone strength
* Density and microarchitecture
– Predisposition to an increased risk of fracture
* i.e. fragility fractures (following minor trauma)
Low Bone Mass - Osteoporosis: (2 things)
Diagnosis:
- In osteoporosis, bones are thinned due to mineral loss and are vulnerable to fracture.
- Affects trabecular bone more
– Regions with high trabecular bone = fracture sites - Wrist, femoral neck, vertebral bodies
- Diagnosis: DXA scans to assess risk by comparison to healthy young adults
– T-score ≤ -2.5 at any site (e.g. hip, L1-L4)
Osteoporosis - DXA:
2 main clinical sites for osteoporosis diagnosis. – Lumbar spine – Femoral neck
OVERALL risk depends on:(2 things)
OVERALL risk depends on:
(1) starting peak bone mass (BMD)
(2) rate at which it is lost
Do men get Osteoporosis? (2 things)
Yes, but less often than women
* Men have greater bone mass to start (bigger bodies, more muscle, more testosterone) and don’t go through menopause (hormonal fluctuations)
Risk Factors for Osteoporosis (6 things)
Diet: inadequate intakes of protein, key vitamins and minerals (vit D, calcium)
Exercise: lack of weight bearing/impact exercise to stimulate bone formation
Age: bone loss starts to occur ~35 yrs (rate of 0.3-0.5%/yr)
Sex: greater risk to women because women have lower peak bone mass and go
through hormonal changes
Genetics: important determinants of bone density, bone size, bone turnover rates
(racial differences).
Smoking and Alcohol: affect ovarian function, hormone production, nutrient
intakes.
Common Symptoms of Osteoporosis (Name 6)
- Pain in bones and lower back
- Height loss (~1.5 inches every 10 yrs after menopause)
- Night cramps in legs and feet
- Fatigue
- A forward bending of cervical/thoracic spine (dowager’s
hump, kyphosis) - Non-traumatic/fragility fractures (osteoporosis causes 90%
of fractures after age 65).
Common Fragility Fractures: Name 3
Vertebral body compression fractures:
* Loss of height, forward hump
Colles’ wrist fracture:
* Distal radius fracture – break a fall with outstretched hands
Hip fractures:
* At femoral neck, intertrochanteric line, proximal shaft
Incidence of Osteoporotic Fracture by Age Group. Which fracture is most common
Hip, vertebrae, wrist
Relative risk of mortality following fractures:
Hip and spine fractures = increased mortality
PREVENTING AND TREATING OSTEOPOROSIS (Name 5)
- Calcium
- Vitamin D
- Protein
- Exercise
- Medication
Diet - Calcium
RDA for calcium:
– Children (4-8 yrs):
– Youth/adolescents (9-18 yrs):
– Young adults (F 19-50, M 19-70 yrs):
– older adults (F 51+, M 71+ yrs): 1200 mg/d;
RDA for calcium
– Children (4-8 yrs): 1000mg/d; ensure enough for bone growth
– Youth/adolescents (9-18 yrs): 1300 mg/d; ensure enough for bone growth
– Young adults (F 19-50, M 19-70 yrs): 1000 mg/d; maintain bone mass and prevent loss
– older adults (F 51+, M 71+ yrs): 1200 mg/d; prevent bones loss and Osteoporosis
Diet - Vitamin D: ( 4 things)
RDA for Vitamin D:
RDA for Vitamin D:
<70y: 600 IU/d or 15 μg/d; ≥70y: 800 IU/d or 20 μg/d
- Fatty fish, liver, egg yolks, fortified
milk, margarine, juices, sun exposure (UVA/UVB) - Risk for deficiency in Canada…..
- OC recommends that all Canadian
adults take a vitamin D supplement
(specifically, D3 or cholecalciferol)
year-round. - Essential for the absorption of calcium
Diet - Protein and Dairy Products:
Dairy/Milk products:
Adequate supply of amino acids is essential for bone.
Dairy/Milk products:
* High in protein
* Most readily available dietary sources of calcium
* Mandatory fortification with vitamin D in Canada (milk only)
* Contain other micronutrients (Mg, Zn, P, K, B12,Vit A), more per unit energy than any other typical food
Are Canadians getting enough Bone Supporting Nutrients?
for protein, as a % of total kcals, yes. As a relative amount, yes.
