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
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.
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.
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).
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.
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:
Exposure to sunlight:
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.
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:
- Quit smoking
- 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.
|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|
Further information and support
Osteoporosis New Zealand
Phone: (04) 499 4862
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]