Osteoporosis is more common in European and Asian New Zealanders but everyone will experience some loss of bone density as they age. It is estimated one in three women and one in five men aged 50 years or older will suffer a fracture due to osteoporosis.
At birth, bones are soft and harden as calcium and protein build up in them. Bone formation occurs rapidly in infancy, slowing down in childhood before massive bone formation occurs in the teenage years. Your bone density reaches its peak between 30 to 35 years of age and then gradually decreases with age in both men and women.
There is no single cause of osteoporosis but there are many factors that can increase the risk of developing osteoporosis. 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)
- Declining levels of testosterone in men 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 fracture occurs. 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 painful and may lead to disability and loss of independence.
Some subtle signs of osteoporosis are evident with decreasing bone density. 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.
A doctor will discuss your medical history, signs, symptoms and family history. If osteoporosis is suspected a specialised x-ray to measure the bone density is usually recommended.
Bone density testing is usually undertaken using dual energy x-ray absorptiometry (DEXA). DEXA is a precise and painless test that takes about 20 minutes where you lie on a special table while the DEXA machine passes over you. The density of bone is measured at different locations (usually the lower spine and hip) and a formula is used to calculate the overall bone density.
Your bone density is graded by comparing it to the average bone density for a person of similar age, size, and gender.
In some cases, bone density can also be measured using computerised tomography (CT scanning) or ultrasound scanning, though these methods tend to be less precise.
Treatment for osteoporosis will depend upon the results of bone density scans, age, gender, medical history. Treatment most commonly involves lifestyle changes and medications and aims to maximise bone density and reduce the risk of bone fracture.
Reduce hazards and taking care:
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 handrails in areas such as entrance ways 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 (ask about these at GP clinics and pharmacies).
If possible, regular weight-bearing aerobic 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, aim for at least 30 minutes of aerobic exercise at least three times a week.
Resistance training using free weights, body weight or elastic band resistance are also likely to be beneficial.
Prior to beginning any new form of exercise, it is important to consult a doctor to ensure that the proposed exercise is safe for you to undertake. A physiotherapist can advise on exercises appropriate to your capabilities.
Eating a balanced diet that includes foods rich in calcium and vitamin D is important to give your bones the calcium they need. Vitamin D is essential as it promotes absorption of calcium into the bones.
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.
As a guide, a 250ml glass of milk will provide around 360mg of calcium and a pottle of yoghurt is around 195mg. Other examples of calcium contents include a cup of boiled broccoli (59mg), 100 grams of tofu (105mg), calcium fortified soy drink (286mg), and 10 raw almonds (30mg).
Foods high in vitamin D include sardines, tuna, eggs and liver.
Smoking, alcohol and caffeine:
Smokers should stop smoking as it increases the rate of bone loss. Restricting alcohol and caffeine intake (eg: tea, coffee, cola drinks) may also be recommended. Excessive alcohol consumption may reduce bone growth while caffeine consumption has been linked to reduced bone density in women.
Exposure to sunlight:
Regular but moderate exposure to sunlight helps to produce vitamin D in the body. Note: excess sun exposure poses other health risks.
In general, getting calcium from the food you eat 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. Note: too much calcium, especially in the form of supplements, has been associated with an increased risk of kidney stones and heart disease.
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 are usually given in conjunction with calcium supplements.
These non-hormonal medications (eg: alendronate, zoledronate) 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. A common side effect of these medications is nausea and indigestion, which can limit their use in some people.
These drugs (eg: denosumab) inhibit the development of cells that break down bone. They produce similar or better bone density results than bisphosphonates and lower the risk of all types of fractures.
Bone formation drugs:
If other osteoporosis medications do not work well enough or are not well tolerated, use of teriparatide may be suggested. Teriparatide is a synthetic form of a hormone that stimulates bone growth.
Menopausal hormone therapy (MHT):
Menopausal hormone therapy (also 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 MHT has 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 you and your doctor discuss the benefits and risks of MHT.
Selective Oestrogen Receptor Modulators (SERMs):
SERMS (eg: raloxifene), which are also used in the treatment of breast cancer, can be used to prevent and treat osteoporosis. SERMS work by mimicking the effects of oestrogen on bone, thus increasing bone density, and may be considered for use in post-menopausal women who cannot tolerate oestrogen.
Fractures are the main consequence of osteoporosis. Most tend to heal without the need for surgery. Sometimes, however, a fracture may be severe enough to require surgery to correct it.
Hip fractures – considered among the most serious types of fracture – are common in elderly people with osteoporosis. It is estimated that about 4,000 people in New Zealand fracture a hip each year.
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:
- Limit alcohol intake
- Eat high calcium-containing foods
- Do regular weight bearing exercise
- Maintain a healthy body weight
- Use of MHT for women during menopause.
Having an adequate dietary calcium intake throughout life is also vital. In New Zealand the Ministry of Health recommends the following daily intake of calcium for healthy individuals:
Children 9-13 years 1,000-1,300 mg
Adolescents 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
Note: the requirements for pregnancy and breastfeeding are not increased above the requirements for women who are not pregnant or breastfeeding.
Further information and support
For information or support contact a doctor, practice nurse, public health nurse or women’s health centre. Information is also available from:
Osteoporosis New Zealand
Phone: (04) 499 4862
E-mail: [email protected]
Mayo Clinic (2019). Osteoporosis (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/osteoporosis/symptoms-causes/syc-20351968 [Accessed: 01/04/20]
National Health and Medical Research Council, Australian Government Department of Health and Ageing, and New Zealand Ministry of Health (2017). Nutrient reference values for Australia and New Zealand (Website). Canberra: Australian Government Department of Health and Ageing. https://www.nrv.gov.au/nutrients [Accessed: 01/04/20]
Osteoporosis New Zealand (Date unknown). All about osteoporosis (Pamphlet PDF). 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: 01/04/20]
Nutrition Foundation (2018). Calcium (Web Page) https://nutritionfoundation.org.nz/nutrition-facts/minerals/calcium [Accessed: 16/04/20]
Last Reviewed – April 2020
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