aging and disease lecture 6- musculoskeletal system Flashcards
what is the social and physical impact from age related conditions?
- Pain
- Limited mobility
- Reduced quality of life
- Direct expenditure on diagnosis and treatment
- Indirect cost from loss of labour force
what are stats for aged related conditions of musculoskeletal systems?
-8.75m people aged 45 and over in the UK have sought treatment for osteoarthritis
-3m people in the UK have osteoporosis
-Over 300,000 fragility fractures occur in the UK each year
-78% of people with arthritis experience pain most days
-hip fracture costs £1.9b per year in the uk
what is osteoporosis?
- Loss in bone density
- Osteopenia
– 1 – 2.5 standard deviations below mean peak bone mass - Osteoporosis
– bone mass at least 2.5 SDs below mean - Often only diagnosed following a fracture
what are the risk factors of osteoporosis?
- Age
- Physical activity
- Calcium nutritional state
- Hormones
- Genetic factors
how does osteoporosis occur?
- Bone undergoes remodelling
throughout life - Imbalance between rates of
resorption and formation can
lead to bone loss - Reduced osteoblast number
- Reduced proliferative and
biosynthetic potential - Cellular response to growth
factors is reduced
how does physical activity help osteoporosis?
- Stimulates bone remodelling
- Load magnitude has a greater influence on
bone density than number of load cycles - Physical activity tends to decrease with age
- Linked to decrease in skeletal muscle mass
- Wolff’s law
what’s the relationship between calcium and osteoporosis?
- Bone comprises cells in a mineralised matrix
- Matrix
– Organic portion – protein fibres
– Inorganic portion – calcium and phosphate salts - NHS recommend a bone-friendly diet
- Calcium and Vitamin D are important
what is the relationship between calcium and vitamin d in osteoporosis?
> absorption of Ca2+ from GI tract
kidney reabsorption of Ca2+
<Ca2+ release from bone
* Main source is sunlight
* Also from oily fish, eggs and
fortified foods
* Deficiency in adolescence can
lead to low peak bone mass
* Gut absorption decreases with
age
what is the relationship between hormones and osteoporosis?
- After the onset of menopause, women lose an
average of 2.5% of bone per year - Decrease in oestrogen production
- Increased osteoclast activity
- Calcitonin and parathyroid hormone (PTH) regulate
bone calcium
– Age-related increase in PTH - Glucocorticoids increase bone resorption
– Glucocorticoid medication can lead to steroid-induced
osteoporosis
– Age-related changes in glucocorticoids
what is the relationship between genetic factors and osteoporosis?
- Up to 40% of variance in bone loss may be
attributable to genes - Genetic studies
– Cell growth pathway genes
– Bone mineral density genes
– Metabolism genes - Some genes associated with osteoporosis have
also been linked to sarcopenia, osteoarthritis
and obesity
what are synovial joints in osteoarthritis?
- Permit free movement of bones
- Flexibility declines with age
- Cartilage thins and changes
what is cartilage in osteoarthritis?
- Decrease in water content
- Changes to matrix proteins, e.g. collagen
- Senescence in chondrocytes
who does osteoarthritis affect?
- Affects almost half of over 75s
- Prevalence higher in women
- Also associated with
– Obesity
– Occupation
– Genetics
what is sarcopenia?
- Loss of skeletal muscle mass
and function - Up to 50% mass loss by age
70 - Reduction in size and
number of muscle fibres - Infiltration of fibrous and
adipose tissue into muscle - Reduction in satellite cells
- Associated with disease,
insulin resistance, fatigue,
falls and mortality
how are these conditions prevented?
- Exercise
– Maintains muscle mass
– Increases bone density
– Increases number of mitochondria - Nutrient intake
– Calcium
– Vitamin D
– Lean protein - Calorific restriction?
– Metformin/resveratrol - Drugs
– Bisphosphonates
– Hormone replacement therapy - Whole body vibration
