|
|
Osteoporosis
Osteoporosis is a disease characterised by low bone mass and
deterioration of bone strength. Fragile bones are more prone to
fracture. Common fractures include wrist, arm, leg and ribs, as well as
the hips and spine. Osteoporosis is often called 'the silent thief'
because bone loss occurs without symptoms.
Individuals may not know they have osteoporosis until their bones
are so weak that a strain, bump or fall causes a fracture. In
Australia, two in three women, and one in three men over the age of 60
will suffer an osteoporotic fracture in their remaining lifetime.
Currently over 2 million Australians are affected by the disease.
Osteoporotic problems cost the Australian community an estimated $1
billion per year in direct costs. The total cost, which includes
factors such as carers and lost income, is estimated to be $7 billion
per year (or $20 million every day). Aside from these financial costs,
fractures often affect mobility, lead to loss of confidence and quality
of life, and increases the risk of dying prematurely.
Although osteoporosis usually occurs in older people, it can be seen in children and young adults
Through childhood and adolescence, our bones increase in strength
and density. Bone mass reaches its maximum density at around 25 years
of age and then drops off slowly. Adverse lifestyle habits such as
smoking, excessive drinking or an unhealthy diet can influence peak
bone mass. A low peak bone mass puts individuals at greater risk of
osteoporosis in later life, even with the normal rates of bone loss. As
the bone mineral content falls, the fragility of the bones increases,
and so does the risk of fractures.
Osteoporotic fractures are generally diagnosed by the use of x-rays.
However, a painless bone density test is much more effective as it
allows osteoporosis to be detected before fractures occur, and
treatment can commence without delay. These tests are widely available
at virtually all major hospitals and medical centres.
The factors that increase your likelihood of developing osteoporosis
are:
- Gender – you are more likely to develop osteoporosis if you are
female
- Being post-menopausal – the loss of oestrogen after menopause is a
major risk factor
- A family history of osteoporosis – inherited factors account for a
major part of an individual's disease risk
- Limited physical activity and inadequate dietary calcium
intake
- Limited exposure to sunlight resulting in low vitamin D intake
- Cigarette smoking and excessive alcohol intake
- Prolonged use of certain medications such as high dose
cortisone
- Some diseases, including hyperparathyroidism and intestinal
malabsorption
There are treatments that help patients cope with fracture pain, as
well as those that increase and maintain bone density, and those that
supply the missing key elements involved in bone strength.
They include:
- Hormone replacement therapy (HT), which largely prevents bone loss
in postmenopausal women and can reduce fracture risk
- Bisphosphonates, which prevent bone loss and rebuild lost bone
mass
- Selective oestrogen receptor modulators (SERMs), which help
increase bone density and therefore reduce fracture risk
- Strontium ranelate, which reduces fracture risk but the mechanisms
of action are not well understood
- Vitamin D supplements, which are particularly important for
individuals who are unable to get enough vitamin D from sunlight
The best strategy for osteoporosis is prevention; a balanced diet
rich in calcium and vitamin D, and regular exercise that includes
weight-bearing exersise (eg. running, skipping, weights) at least three
times a week, can help. It is also useful to have regular bone density
tests after the age of 60.
Garvan’s bone and mineral research combines clinical, molecular, and
cellular research to explore the links between genetic, hormonal and
lifestyle influences on the achievement of optimum bone mass.
In our molecular research, scientists have discovered that the brain
hormones leptin and neuropeptide Y have different effects on bone
formation, which could lead to the identification of new treatments for
osteoporosis. Our research has also uncovered two gene variants that
put post-menopausal women at an increased risk of having a hip
fracture.
More recently, other genetic markers that indicate low risk of
osteoporotic fractures have been identified. Markers such as these
provide a starting point for genetic testing for osteoporosis, and most
importantly suggest novel targets for potential therapies.
The research draws on the Dubbo Osteoporosis Epidemiology Study (DOES),
which is the world’s longest running large-scale epidemiological study
of osteoporotic fractures in men and women. This study, which began
in1989, involves over 3500 participants in the NSW regional centre of
Dubbo and aims to identify the lifestyle factors that contribute to
improvement or deterioration of our bones. In addition to this
population study, Garvan is also conducting a genetic study with over
400 members of large extended families, in order to pinpoint the genes
important to bone health.
Results from DOES recently identified that, contrary to popular belief,
osteoporosis is not just a woman’s disease. While women are initially
twice as likely as men to have a first fracture, the risk of a man’s
second fracture substantially increases to the point where it is the
same as in women.
Garvan scientists are now developing a screening model for doctors to
identify, at an early stage, people who have a high risk of fracture.
These patients are the ones who could most benefit from preventative
therapies. The screening model includes simple tests of postural
ability that, in conjunction with bone mineral density measurements,
could be used to better predict fracture risk.
News
We now know that the brain controls the formation of bone
MEDIA RELEASE:
22 Dec 2009
New findings show that bone formation, far from being a straightforward mechanical process dependent on body weight, is delicately orchestrated by the brain, which sends and receives signals through the body’s neural and hormone systems.
Summarising a fractured debate about meat, fish, eggs, vegetables and bones
MEDIA RELEASE:
02 Jul 2009
Until now, medical opinion about the impact of vegetarian diets on bone health has been based on anecdotal evidence and a range of contradictory findings that sometimes rely on studies too small to be biologically relevant. A review and analysis of all relevant existing research shows that differences in bone mineral density between meat eaters and all vegetarians is 5%. The jury is still out on whether that translates into higher fracture risk.
|
