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Postmenopausal women are more likely to develop osteoporosis: a condition characterised by weakened bones that fracture easily.
The female sex hormone oestrogen plays an important role in maintaining bone strength. The drop in oestrogen levels that occurs at menopause may result in increased bone loss. It is estimated that the average woman loses up to 10 per cent of her bone mass in the first five years after menopause.
 Menopause and osteoporosis 90.35 Kb
Peak bone mass is reached when the skeleton has stopped growing and bones are at their strongest. This usually occurs in young adulthood. If the peak bone mass before menopause is less than ideal, the bone loss during menopause may result in osteoporosis. Research suggests that about half of all women over the age of 60 years will have at least one fracture due to osteoporosis.
What is osteoporosis?
Within bones a continuous balanced process of formation and breakdown (called resorption) occurs. Osteoporosis occurs when resorption is greater than formation, leading to loss of bone strength and density. The bones thus become fragile and fracture (break) more easily.
Usually there is no sign that osteoporosis is developing until a fracture occurs. Breaks are most common in the spine, hip and wrist, and often occur after only a minor fall. Osteoporotic fractures of the spine cause loss of height, pain and gradual development of the ‘dowager's hump'.
Diagnosing osteoporosis
Osteoporosis is commonly diagnosed using a specialised x-ray technique (DEXA). A DEXA measures bone mineral density and presents the result as a T score. The T score compares the bone density of the woman being scanned with that of a young woman (when peak bone mass is at its best).
The various T scores used in diagnosis are:
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Normal bone density is when the T score measures greater than -1.
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Osteopaenia is diagnosed when T scores are between -1 and -2.5. This means there is some loss of bone mineral density, but it is not severe enough to be called osteoporosis.
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Osteoporosis is diagnosed when the T score measures -2.5 or less. Osteoporosis is also diagnosed when a person has a minimal impact fracture, regardless of the T score.
Preventing osteoporosis
Lifestyle changes
During menopause a woman can reduce her risk of developing osteoporosis by making a few lifestyle changes:
- Adequate dietary calcium (equivalent to three to four serves of dairy food per day).
- Maintain adequate vitamin D levels - approximately five to 15 minutes of sunlight (before 10am and after 2pm) will provide the necessary daily requirement (this varies depending on the season and where you live). Some people are unable to obtain adequate vitamin D through sun exposure and vitamin D supplements may be required.
- Do regular and appropriate physical activity.
- Stop smoking.
- Use caffeine and alcohol only in moderation.
Ideally, these lifestyle habits should be in place from childhood and during adolescence to maximise bone mass before menopause.
Physical activity
Exercising regularly throughout life can reduce the risk of osteoporosis. Doing some type of physical activity on most days of the week for 30-40 minutes is recommended. Physical activities that are beneficial in preventing fracture are weight bearing and resistance training exercises.
Weight bearing exercise refers to any exercises performed on your feet. Examples include walking, running, tennis, Tai Chi and dancing. Studies to evaluate the effects of exercises such as walking have not shown a significant improvement in bone mass unless this activity is performed as a high intensity activity (e.g. walking at a fast pace, jogging).
Resistance training exercises are also known as strength training exercises. Strength training uses weights of some kind - for example machines, dumbbells, ankle or wrist weights - to create resistance, which helps build muscle mass and places a load (force) on the involved limb bones. It also includes exercises using your body weight as the load, such as push-ups where the load is placed through the arms and shoulders.
Physical activity will improve muscle strength, balance and fitness and also reduce the incidence of falls and fractures.
General recommendations for physical activity
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Avoid high impact activities or those that require sudden, forceful movements
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Do weight bearing exercise such as Tai Chi, dancing and weight training
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Do aerobic activity two or three times a week
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Undertake strength training once or twice weekly
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Include flexibility exercises or stretching
Be guided by your healthcare professional when deciding on your exercise program.
Medical prevention and treatments
While prevention is best, there are a number of medical treatments available for the management of osteoporosis. These include:
Vitamin D deficiency is common in Australia. Studies indicate that 30 to 50 per cent of postmenopausal women are deficient in vitamin D, at various times of the year. Studies also show that up to 60 per cent of postmenopausal women are not meeting their required dietary calcium intake. Vitamin D is important for assisting in the deposition of calcium into bone. Calcium is the main mineral within the human skeleton. Fifteen to twenty minutes of exposure to sunlight every day can also boost vitamin D production and contribute to bone health.
When taking specific osteoporosis therapies, there may be a requirement for additional vitamin D and calcium supplements if measured vitamin D levels are low or dietary calcium intake is insufficient. The need for supplementation will be determined by your physician.
Recently, an observational study in older women suggested one gram of calcium supplement (more than one tablet daily) may increase the risk of heart disease. Further research is needed.
Bisphosphonates
Bone cells are constantly being broken down and renewed. Bisphosphonates prevent bone loss by reducing bone resorption. Possible side effects of treatment include gastrointestinal upset and in particular, gastroesophageal reflux (heartburn), and a rare but important side effect of osteonecrosis (death of bone) of the jaw. Bisphosphonates may be taken daily or weekly, but are only available on the Pharmaceutical Benefits Scheme with restrictions (either any age with a low impact fracture OR persons over 70 years with a T score less than -3.0). The most commonly used bisphosphonates in Australia are alendronate (Fosamax) and risedronate (Actonel).
Selective oestrogen receptor modulators (SERMs)
The female body contains oestrogen receptors, which are located on many body tissues including bone.
These receptors respond to the hormone oestrogen. Selective oestrogen receptor modulators (SERMs) are medications that work by blocking the oestrogen effect at some receptor sites, while prompting an oestrogen effect at others. In bone they work like oestrogen and lead to an increase in bone mass (density). The most common SERM in use in Australia is raloxifene (Evista). Potential side effects of SERMs include hot flushes and a slight increased risk of deep vein thrombosis (DVT), but SERMs do not increase the risk of breast cancer.
Hormone therapy
Hormone therapy (HT) (also known as hormone replacement therapy (HRT)) relieves menopausal symptoms such as vaginal dryness, hot flushes and night sweats. When taken at the beginning of menopause, HT can also prevent bone loss and should be started soon after menopause for maximum benefit. Some studies have shown that HT can increase bone density by around five per cent in two years. On average, HT reduces the risk of spinal fractures by 40 per cent. Bone loss will resume once HT is stopped.
The use of hormone therapy for prevention of diseases, such as heart disease or stroke, is not recommended. However, some women may elect to use hormone therapy for osteoporosis - this needs to be done in consultation with the woman's treating physician and the woman needs to understand the risks and benefits of this therapy.
HT started after the age of 60 years has a higher risk of cardiovascular disease (stroke and heart attack) and DVT than if used nearer the menopause. However, there is evidence that there is a therapeutic window of opportunity for use of hormone therapy for the prevention of cardiovascular disease, if it is started at the time of onset of menopause (around 50 years of age), before atheromatous plaques (blockages) develop in the arteries. This benefit appears to be lost if HT is started in women after the age of 60 years when plaque has already developed in the arteries. It may be at this stage that the use of HT may destabilise these plaques and lead to cardiovascular disease.
This therapy is a different form of hormone therapy with the same benefits for relieving menopausal symptoms. There is evidence that tibolone has beneficial effects on bone and leads to an increased bone density and fracture prevention. It may have the same risks as conventional HT.
Strontium ranelate (Protos)
Strontium is a trace element that is naturally found within soft tissues, blood, teeth and bone. How it works is unclear, but it seems to lead to decreased bone loss and may enhance bone formation. Studies with this medication in postmenopausal women have shown a reduction in vertebral (spinal), hip and other fractures.
This medication has recently become available in Australia for the treatment of postmenopausal osteoporosis under the PBS. It is taken in the form of granules which are dissolved in water and should be taken at bedtime at least two hours after eating. It appears to be well tolerated, but may be associated with side effects of diarrhoea, nausea and headache. There is also a slight risk of DVT. There is a rare but important side effect of a hypersensitivity rash and abnormal liver function tests.
Teriparatide (Forteo)
This is like an artificial parathyroid hormone that is administered daily via a subcutaneous (just below the skin) injection. It functions to increase bone formation and absorption of calcium from the gut and kidney. Calcium and vitamin D supplements may be necessary with this medication and must be monitored under the care of a specialist physician. Most of the studies with this medication have only been for up to two years.
In Australia, treatment is limited to one 18 month course per lifetime. There appears to be a clear benefit in terms of reducing all types of fractures in postmenopausal women, except for hip fractures. The lack of benefit in preventing hip fracture may have been due to the way the studies were designed. This therapy became available in Australia in November 2003 and is not currently listed for use by the PBS. Due to the expense and limited access of this therapy, it is not readily available to all Australians. Its prescription for use is confined to specialists in osteoporosis.
Where can I get more information?
http://www.jeanhailes.org.au/
http://www.bonehealthforlife.org.au/
http://www.menopause.org.au
http://www.osteoporosis.org.au/ - Osteoporosis Australia (02) 9518 8140
This fact sheet has been developed by the Australasian Menopause Society in partnership with The Jean Hailes Foundation for Women's Health.
Note: Medical and scientific information provided and endorsed by the Australasian Menopause Society might not be relevant to a particular person's circumstances and should always be discussed with that person's own healthcare provider.
This Information Sheet may contain copyright or otherwise protected material. Reproduction of this Information Sheet by Australasian Menopause Society Members and other health professionals for clinical practice is permissible. Any other use of this information (hardcopy and electronic versions) must be agreed to and approved by the Australasian Menopause Society.
Content Updated June 2008
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