There is no single cause of osteoporosis but there are many risk factors. These include:
- Older age (>50 years)
- Female gender
- Thin build
- Physical inactivity
- Family history of osteoporosis
- Excessive alcohol or caffeine consumption
- Low dietary calcium intake
- Low levels of vitamin D
- Long-term use of some medications eg: corticosteroids (such as prednisone and cortisone), thyroid medications, epilepsy medications
- Deficiency of oestrogen in women eg: post-menopausal, irregular periods, surgical removal of the ovaries, early menopause (before the age of 40 years)
- Deficiency is testosterone in men due to declining levels of testosterone with ageing
- Treatments for prostate cancer that reduce testosterone levels in men and treatments for breast cancer that reduce oestrogen levels in women
- Some medical conditions eg: endocrine diseases such as Cushing's syndrome and thyrotoxicosis; gastrointestinal diseases such as coeliac disease and Crohn's disease; rheumatoid diseases such as rheumatoid arthritis; and blood disorders such as multiple myeloma.
Signs and symptoms
There are usually no symptoms of osteoporosis until a bone breaks. For this reason it is often referred to as a "silent disease". Fractures of the wrist, hip, spine, pelvis and upper arm are most common in osteoporosis. The fractures can be very painful and can lead to disability and loss of independence.
Over time there may be a gradual loss in height due to weakened and compressed vertebrae in the spine. Spinal fractures or crumbling of affected vertebral bones can lead to a Dowager’s Hump or Widow’s Hump. This results in an increasingly bent-over posture and may cause back pain.
Treatment for osteoporosis will depend upon the results of bone density scans, age, gender, medical history and the severity of the condition. Treatment most commonly involves lifestyle changes and medications and aims to maximise bone density and reduce the risk of bone fracture.
If possible, regular weight-bearing exercise (eg: walking, tennis, golf) should be maintained as it can help to reduce bone loss and stimulate new bone formation. To be of benefit, doctors recommend at least 30 minutes of exercise at least three times a week. Prior to beginning any new exercise it is important to consult a doctor to ensure that the proposed exercise is safe to undertake.
As the body cannot make its own calcium, a diet high in calcium is necessary and helps to slow the rate of bone loss. Vitamin D is also essential as it promotes absorption of calcium into the bones. Eating a balanced diet that includes calcium and vitamin D-rich foods is important in supplying the bones with the calcium required. Foods high in calcium include dairy products, dark green vegetables, beans, legumes, fish (especially sardines or salmon which are eaten with the bones), soybean products, cereals and nuts. It is recommended that at least 1000mg of calcium is taken in each day. Foods high in vitamin D include sardines, tuna, eggs and liver.
Smokers will be advised to stop smoking. Minimizing alcohol and caffeine intake (eg: tea, coffee, cola drinks) may also be recommended.
Regular but moderate exposure to sunlight helps to produce vitamin D in the body. Note - excess sun exposure poses other health risks.
It is important to take extra care with movement and daily activities in order to minimise the risk of fractures. This can include using mobility aids if unsteady on the feet, removing objects or hazards that can lead to falls (eg: loose floor rugs), installing hand rails in areas such as entranceways and bathrooms, and using non-slip mats in the bath or shower. Padding to protect vulnerable parts of the body eg: the hips, can also help in the prevention of fractures. Special "hip protectors" have been developed for this purpose. These can be enquired about at GP clinics and pharmacies.
In general, calcium from the diet is preferred to calcium supplements. However, if dietary intake of calcium is insufficient, calcium supplements may be prescribed in order to increase the amount of calcium available in the body. A dosage of 1000mg per day in usually recommended. Note - too much calcium, especially in the form of supplements, has been associated with an increased risk of kidney stones and heart disease.
Vitamin D is important for the effective absorption of calcium into the bones. Most people get adequate amounts of vitamin D from sunlight; however, for people who rarely go outside (eg, the frail elderly) or people who stay covered up when outside, vitamin D supplements may be beneficial. Vitamin D supplements such as calciferol are usually given in conjunction with calcium supplements. An activated form of vitamin D called calcitriol has also been shown to be beneficial.
These non-hormonal medications can increase bone density by reducing the rate of bone loss. They have been shown to reduce the fracture rate in people with osteoporosis. These medications are usually given in an alternating cycle with calcium supplements. Common bisphosphonate medications used in the treatment of osteoporosis include alendronate (Fosamax) and zoledronic acid (Aclasta). A common side effect of these medications is nausea and indigestion. This can limit their use in some people.
Menopausal hormone therapy (formerly known as hormone replacement therapy or HRT) medications that include oestrogen are sometimes recommended for women with osteoporosis. MHT has been shown to reduce bone loss and may increase bone density. While MHThas obvious benefits in the treatment and prevention of osteoporosis, research has indicated that there are risks with long-term MHT use including an increased risk of blood clots, endometrial cancer and breast cancer. It is therefore important that the patient and their practitioner discuss the benefits and risks of taking the medication.
Prevention is better than treatment and evidence suggests that maximising bone density in early and middle life helps to reduce the risk of osteoporosis in later life. Steps that can be taken to help prevent osteoporosis include:
- Stop smoking
- Limit alcohol intake
- Eat high calcium-containing foods
- Undertake regular weight bearing exercise
- Maintain a healthy body weight
- Consider MHT for women during menopause
|Children||9-13 years||1,000-1,300 mg|
|Children||14-18 years||1,300 mg|
|Men||19-70 years||1,000 mg|
|Men||70+ years||1,300 mg|
|Women||19-50 years||1,000 mg|
|Women||50-70+ years||1,300 mg|
Further information and support
Phone: (04) 499 4862
National Health and Medical Research Council, Australian Government Department of Health and Ageing, New Zealand Ministry of Health (2017). Nutrient reference values for Australia and New Zealand including recommended dietary intakes (Guidelines). Canberra: Australian Government Department of Health and Ageing. https://www.nhmrc.gov.au/_files_nhmrc/file/publications/17122_nhmrc_nrv_update-dietary_intakes-web.pdf
Osteoporosis New Zealand (Date unknown). All about osteoporosis (Pamphlet). Wellington: Osteoporosis New Zealand. https://osteoporosis.org.nz/wp-content/uploads/OsteoNZ-DL-Brochure-WEB.pdf
Osteoporosis New Zealand (2017). Osteoporosis and fractures (Web Page). Wellington: Osteoporosis New Zealand. http://osteoporosis.org.nz/osteoporosis-fractures/what-is-osteoporosis/ [Accessed: 12/06/17]