Bone density reduces to some degree in all people as they age. Osteoporosis is a condition where the bones become excessively thin and weak, such that there is a greater risk of fractures. It affects more than 50% of women and about 30% of men over 60 years, as well as a few younger people. Osteoporosis is often called the ‘silent disease’ as it can develop without any symptoms, until you find you have broken a bone.
How does bone grow?
Bone is a living tissue that grows in a porous mesh-like structure. Throughout life the body breaks down old bone and rebuilds new bone in a continuous cycle. We gain bone by building more than we lose.
Bones contain the protein collagen and minerals such as calcium and phosphorus, which make the collagen hard and dense. To maintain bone density, the body needs adequate calcium and other minerals and certain levels of hormones, including oestrogen in women and testosterone in men.
Vitamin D is needed so the body can absorb calcium from food and incorporate it into bones. Physical activity (especially weight-bearing exercise) also helps bone become dense.
|Interior of healthy bone.
||Interior of thin, porous bone.|
How does bone become thinner?
Bones grow more and more dense until around the age of 30. After about 40, bone breaks down slightly faster than it is replaced and bones slowly become less dense.
In women, after the menopause, the ovaries stop releasing eggs and the level of oestrogen decreases. Over many years, a low oestrogen level causes the inner mesh of bones to become thinner, weaker and more brittle. In men, this can happen if there is too little testosterone.
Other possible causes of bone loss include long-term use of some medications (eg, anticonvulsants or steroids such as prednisone). Medical conditions can also be factors, such as rheumatoid arthritis, liver disease, coeliac disease, hyperthyroidism, Cushing’s syndrome, among others.
Having low intakes of calcium in the diet and not getting enough vitamin D (mainly from sunlight) puts people of all ages at risk of low bone density and poor bone health. People who are inactive are also at risk, as physical activity helps bone become denser.
Younger people can also be affected by osteoporosis. Younger women with eating disorders such as anorexia or bulimia are at higher risk of developing osteoporosis, as are those younger women who do too much exercise and stop having periods.
Am I at risk for osteoporosis?
Some people are more at risk than others. The following risk factors are linked to having osteoporosis, or getting it later on. The more of these that apply to you, the more important it is to discuss osteoporosis with your doctor:
- being female^
- previous fracture due to osteoporosis
- family history of osteoporosis#
- being aged 50 years or older
- being past the menopause
- having your ovaries removed or reaching menopause before the age of 45
- being thin or ‘small boned’
- White (Caucasian) or Asian ancestry
- lifestyle risk factors (below)
^men can also develop osteoporosis, though it is more common in women
#genetics is thought to influence bone health and the risk of developing osteoporosis, together with environmental factors.
Modifiable risk factors - lifestyle
In addition, risk factors which you may be able to modify include:
- too little calcium in your diet - less than four servings of dairy products a day
- alcohol (more than two standard drinks a day)
- less than 30 minutes outdoors in sunlight each day
- less than 30 minutes of physical activity each day
- long term use of some medications, such as steroids (eg, cortisone, prednisone) or anticonvulsants [discuss risk with your doctor].
These are risk factors you can have some control over throughout your life to reduce the chances of osteoporosis in old age. For osteoporosis, prevention is far more successful than treatment.
How can my doctor help?
Your doctor can assess your risk for osteoporosis from your medical history and by asking you about your lifestyle. Physical signs that you may have weak bones include previous fractures (often of the wrist, hip or spine), a loss of height or stooping, and a curved spine. Your doctor may suggest you have a bone density scan (a type of x-ray) to check for bone weakness.
What can be done about osteoporosis?
If you have weak bones there are practical steps you can take in consultation with your doctor - these depend on your age, gender, medical history and the degree of bone thinning. These measures will help you avoid a fracture and maintain your quality of life. Unfortunately, once you have had one osteoporotic fracture, you are more likely to have others.
Weight-bearing exercise, such as walking or climbing stairs, can help bone become denser. It is a good idea to start this after having a check-up with your doctor. Stopping smoking and drinking only small amounts of alcohol also helps prevent further bone loss. Calcium and vitamin D are also important (see further below).
To reduce your risk of injury in day-to-day life:
- plan your movements
- avoid straining your back or falling by, for example, wearing slip-proof shoes, putting slip-proof mats in the bath and shower, and always holding handrails
- be careful when lifting, bending or reaching
- use any cane or walker correctly and consistently
- if you fall, make sure you are unhurt before moving
- if you fall, ask your doctor to check your health; your eyesight or medications may need checking.
Also see: Falls Prevention
There is no complete cure for osteoporosis, but there are supplements and medicines that can increase bone thickness and reduce fracture risk. Discuss with your doctor before using supplements.
Diet: In food choices, aim for low-fat dairy options. A 250ml glass of milk contains about 300mg calcium; there are also higher-calcium versions available. In non-dairy options, soy milk is usually fortified with calcium - check the product label. Calcium is also found in other foods, eg, dark green leafy vegetables, almonds, sardines, salmon with bones, tofu.
Supplements: Some people may have difficulty getting enough calcium from food sources (approx four serves of dairy per day) and so calcium supplements may be recommended. However, there is some disagreement over the use of calcium supplements, as some studies have shown an increased risk of heart problems from taking these, particularly in older adults. Calcium supplementation slows bone loss but does not usually stop it completely (loss of bone calcium is common in older age). It is best to discuss calcium supplementation with your doctor.
Vitamin D supplementation
This supplementation can correct vitamin D deficiency, which is common in older people who are seldom outdoors. Vitamin D is mainly produced in the body by the action of sunlight on skin. Vitamin D helps you absorb the calcium in your diet and your bones to utilise it. Talk to your doctor about your vitamin D status. You may be prescribed a supplement if your sunlight exposure is low.
Also see: Vitamin D and sun safety
Calcitriol is also a form of vitamin D that helps the body absorb calcium and incorporate it into bone. However, supervision by a doctor is needed as it can raise calcium too much.
There can be side effects from treatments, and your doctor should discuss with you possible risks versus benefits of taking a medicine.
Bisphosphonates are bone-specific medicines that increase bone density and reduce fractures. They are often used as a treatment for osteoporosis. It is important to take the tablets as advised; that is, on an empty stomach with plenty of water (not tea, coffee or juice), remaining upright (sitting or standing) and not taking other foods or medications for at least half an hour. This will help the medicine to be absorbed as well as help to prevent any side effects such as indigestion. Some patients take bisphosphonates as a once-yearly intravenous infusion instead of tablets.
Hormone replacement therapy (HRT)
Hormone replacement was previously commonly used as a treatment for osteoporosis in women with low oestrogen levels (usually due to the menopause). HRT increases bone density and reduces fracture rates. However, it also increases the risks of blood clots, breast and uterus cancer, heart attacks and strokes, in older postmenopausal women in particular. For these reasons HRT use is no longer widely recommended for osteoporosis; however, it may still be considered a useful option for osteoporosis in some circumstances.
Men with low testosterone levels may also benefit from testosterone replacement.
Other types of treatment may be used, depending on your individual health factors and whether you have other medical conditions. These include SERMS (selective oestrogen receptor modulators) such as raloxifene; tibolone metabolites; and strontium ranelate; among others.
In most cases your GP will be able to diagnose osteoporosis and manage your treatment. Specialist referral may be needed in some cases, for example, severe osteoporosis.
Original material by everybody. [Images provided by The StayWell Company © 2001. All rights reserved.] Text updated by everybody, April 2013.