Osteoporosis

• In childhood new bone is formed very rapidly allowing our bones to grow in length.
• In our teens and early 20s the bones stop growing in length but continue to grow in density and strength. Bone density reaches its peak by our mid-20s.
• After this, new bone continues to be produced at about the same rate as older bone is broken down. This means that the adult skeleton is completely renewed over a period of 7–10 years.
• Eventually, bone starts to be broken down more quickly than it is replaced, so that our bones gradually begin to lose their density. This phase usually starts at about the age of 40 and continues for the rest of our lives.

Everybody will have some degree of bone loss as they get older, but the term osteoporosis is only used when the bone loss is sufficient to make them significantly more fragile.

Women are more likely than men to develop osteoporosis for two main reasons:

• The process of bone loss speeds up for several years after the menopause, when the ovaries stop producing the female sex hormone oestrogen. This accelerated bone loss can lead to an imbalance and cause osteoporosis
• Men generally reach a higher level of bone density before the process of bone loss begins. Bone loss still occurs in men but it may never reach a point where the bone is significantly weakened.

However, a number of other risk factors can affect our individual chances of developing osteoporosis and of breaking a bone in a relatively minor accident.

• Corticosteroids – Sometimes known just as steroids, these drugs can increase the risk of osteoporosis by reducing the amount of calcium absorbed from the gut. They can also increase calcium loss through the kidneys. 
• Oestrogen deficiency ­– Women who have had an early menopause (before the age of 45), or a hysterectomy where one or both ovaries have been removed, are at greater risk of osteoporosis. Removal of the ovaries only (ovariectomy or oophorectomy) is relatively rare, but has been associated with an increased risk  of developing the condition.
• Lack of exercise – Exercise keeps the bones strong so people who don't exercise will be more prone to losing calcium from the bones and thus will be more likely to develop osteoporosis.
• Poor diet – A diet which doesn't include enough calcium or vitamin D makes osteoporosis more likely.
• Heavy smoking – Tobacco lowers the oestrogen level in women and may cause early menopause. In men, smoking lowers testosterone activity and can weaken the bones, leading to osteoporosis.
• Heavy drinking – A high alcohol intake reduces the ability of the body's cells to make bone.
• Family history – Osteoporosis does run in families. This is probably because there are inherited factors which affect the development of bone. If a close relative has suffered a fracture linked to osteoporosis, then your own risk of a fracture is likely to be greater than normal.

Spinal problems occur if the bones within the spine (vertebrae) become weak and lose height (termed a crush fracture). If several vertebrae lose height, the spine will start to curve. This may cause back pain and loss of height and some people may have difficulty breathing simply because there is less space under their ribs. However, minor fractures of the vertebrae are not always painful.

The scan involves lying on a couch, fully clothed, for about 15 minutes while your bones are x-rayed. The dose of x-rays is very small – about the same as spending a day out in the sun. The result will place the bone in one of three categories:

• Normal – The risk of a low-impact fracture is low
• Osteopenia – The bone is becoming weaker but the risk of a low-impact fracture is still quite low. You may not require specific treatment but we would recommend thinking about how your risk factors could be reduced
• Osteoporosis – There is a greater risk of low-impact fractures and treatment is likely to be needed.

Who should have a scan for osteroporosis?

There's no good evidence that screening the population, as a whole, for osteoporosis would be helpful. However, if any of the following apply to you, we would recommend that you discuss with your doctor whether or not a scan for osteoporosis is needed:

• You need steroid treatments for 3 months or more
• You have already had a low-impact fracture
• Your menopause occurred before the age of 45
• You are female and your mother or another first-degree relative had a hip fracture before the age of 75
• You have another disease that can affect the bones – for example, coeliac disease, inflammatory bowel disease (Crohn's disease or ulcerative colitis), rheumatoid arthritis, diabetes and hyperthyroidism (overactive thyroid)
• You have a body mass index (BMI) of less than 19 kg per square metre.

Treatment of fractures

This usually requires an orthopaedic assessment as the fracture may need fixing.  Pain relief may also be needed:

• analgesics – such as paracetamol, codeine and occasionally morphine
• non-steroidal anti-inflammatory drugs (NSAIDs)
• bisphosphonates and calcitonin, which have been shown to reduce osteoporosis pain from fractures of the pelvis and vertebrae

Prevention of fractures

Self-help measures can help to reduce the risk of fractures, but a number of specific treatments are also available for people with osteoporosis:

• Calcium and vitamin D – Many people do not have enough calcium in their diet and will benefit from calcium and vitamin D supplements.
• Bisphosphonates – This group of drugs works by slowing bone loss; in many people, an increase in bone density can be measured over 5 years of treatment. There are a number of drugs in this group including alendronate, and risedronate, ibandronate and etidronate. They reduce the risk of hip and spine fractures in patients with osteoporosis. Tablets or intravenous infusions are available.
• Strontium ranelate – This works by both stimulating the formation of new bone tissue and suppressing the breakdown of old bone material. Trials have shown that strontium ranelate reduces the risk of spine and hip fractures, although the overall risk of fractures may not be reduced. Strontium ranelate is particularly helpful in reducing fracture risk in people over the age of 80 and is also useful for people who can't take bisphosphonates.
• Teriparatide – Teriparatide helps new bone formation and therefore reduces the risk of fractures. It is taken by daily injection into the thigh or tummy (patients are shown how to do this themselves). It is used for up to 18 months, during which time the bones are strengthened. At present it is used mainly for people who have had fractures despite using other treatments, or who have had side-effects from other treatments.
• Raloxifene – This belongs to a group of medicines called selective estrogen receptor modulators (SERMs). Raloxifene is given as tablets and mimics the beneficial effects of oestrogen on bone strength, reducing the risk of spinal fractures.
• Hormone replacement therapy (HRT) – HRT is beneficial for the bones while it is being used, but is not recommended as the first-choice treatment for osteoporosis because of the risk of side-effects.
• Calcitonin – Calcitonin is a substance which the body produces naturally and which helps keep the bones healthy. When used as a treatment it has been shown to increase bone strength in people with osteoporosis. Calcitonin is given as injections or as a nasal spray. Injections of calcitonin are normally given only as a short-term treatment for painful vertebral fractures, but the nasal spray may be used as a long-term treatment for osteoporosis.

Exercise

Children should actively take part in sports or other types of exercise to help strengthen their bones in order to lower the chances of developing osteoporosis. For the same reason, adults should keep physically active all the way into retirement.

Weight-bearing exercises (any activity which involves walking or running) are better for bone strength than non-weight-bearing exercises such as swimming and cycling. However all forms of exercise improve co-ordination, reducing the risk of falling and so the risk of fractures.

One notable exception to the beneficial effect of exercise is that women who exercise so intensively that their periods stop have a higher risk of developing osteoporosis.

Diet and nutrition

Children and adults need a diet which contains the right amount of calcium. The best sources of this are milk, cheese and yogurt and certain types of fish which are eaten with the bones. Skimmed or semi-skimmed milk contains more calcium than full-fat milk.

We recommend a daily intake of calcium of 1000 milligrams (mg) to 1500 mg if you are over 60, to lower the chances of developingosteoporosis. A pint of milk a day, togetherwith a reasonable amount of other foods which contain calcium, should be sufficient.

Vitamin D is needed for the body to absorb calcium. Vitamin D is obtained from some foods, especially oily fish, and is converted into the active form when sunlight falls on the skin. It is sometimes necessary to take a supplement containing 10–20 micrograms (µg) of vitamin D, especially for people over the age of 60.