Brittle bones

Introduction

Osteoporosis is a condition that affects the bones, causing them to become weak and fragile and more likely to break (fracture). These fractures most commonly occur in the spine, wrist and hips but can affect other bones such as the arm or pelvis.

Approximately 3 million people in the UK are thought to have osteoporosis, and there are over 230,000 fractures every year as a result. Although commonly associated with post-menopausal women, osteoporosis can also affect men, younger women and children.

Bone is made of a hard outer shell with a mesh of collagen (tough elastic fibres), minerals (including calcium), blood vessels and bone marrow inside. This mesh looks a bit like a honeycomb, with spaces between the different parts. Healthy bones are very dense, and the spaces inside the bones are small. In bone affected by osteoporosis, the spaces are larger, and this makes the bones weaker, less elastic and more likely to break

Bone is a living tissue that is constantly repairing itself. This process is called bone turnover. There are cells which break down old bone (osteoclasts) and cells which build new bone (osteoblasts). This process requires a range of proteins and minerals, which are absorbed from the bloodstream.

In childhood, bones grow and repair very quickly, but this process slows down as you get older. Bones stop growing in length between the ages of 16 and 18, but continue to increase in density until you are in your late 20s. From about the age of 35, you gradually lose bone density. This is a normal part of ageing, but for some people it can lead to osteoporosis and an increased risk of fractures.

Last updated: 04 October 2011

Symptoms of osteoporosis

Osteoporosis develops slowly over several years. It is likely that there will be no warning symptoms before a minor fall or sudden impact causes a bone fracture. Healthy bones should be able to withstand a fall from standing height, so a bone that breaks in these circumstances is known as a fragility fracture.

When the bones are significantly weakened (a low bone mass), breakages of the wrist, hip or spinal bones (vertebrae) are most common. A cough or a sneeze may cause the fracture of a rib or the partial collapse of one of the bones of the spine.

A fractured bone in an older person can be serious, depending on where it occurs. It may lead to long-term disability. For example, a hip fracture may lead to long-term problems with mobility.

One visible sign of osteoporosis is the characteristic stooping (bent forward) position that occurs in older people. It happens when the bones in the spine are fractured, making it difficult to support the weight of the body.

Is osteoporosis painful?

Osteoporosis usually doesn't cause pain unless a bone is broken as a result of the condition. Although not always painful, spinal fractures are the most common cause of chronic pain associated with the condition. 

 

Last updated: 04 October 2011

Causes of osteoporosis

How does osteoporosis develop?

Bones are at their thickest and strongest in early adult life and are constantly renewed and repaired through a process called bone turnover. However, as you age, this process is no longer balanced and bone loss increases. This means that bone is very slowly broken down over time, leading to a decrease in bone density as you get older. This can cause the bone to become weaker and increase your risk of breaking a bone.

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Who is at risk of osteoporosis?

Osteoporosis can affect men and women. It is more common in older people, but it can affect younger people too.

Women

Women are at greater risk of developing osteoporosis than men. This is because changes in hormone levels can affect bone density. The female hormone oestrogen is essential for healthy bones. After the menopause, the level of oestrogen in the body falls, and this can lead to a rapid decrease in bone density. Women are at an even greater risk of developing osteoporosis when:

  • they have an early menopause (before the age of 45)
  • they have a hysterectomy before the age of 45, particularly when the ovaries are also removed
  • their periods are absent for a long time (more than six months) as a result of over-exercising or over-dieting

Men

For most men who develop osteoporosis, the cause is unknown. However, one particular cause of osteoporosis is linked to the male hormone testosterone, which helps to keep the bones healthy. Men continue to produce this hormone into old age, but the risk of osteoporosis is increased in individuals with low levels of testosterone.

Diseases of the hormone-producing glands

Many hormones in the body can affect the process of bone turnover. If you have a disease of the hormone-producing glands, you may be at higher risk of developing osteoporosis. Osteoporosis can be triggered by hormone-related diseases, including:

  • hyperthyroidism (overactive thyroid gland)
  • disorders of the adrenal glands, such as Cushing's syndrome
  • reduced output of sex hormones (oestrogen and testosterone)
  • disorders of the pituitary gland

Other factors

Other factors that can increase the risk of osteoporosis and broken bones include:

  • a family history of osteoporosis
  • a parental history of hip fracture 
  • a low body mass index (BMI of 19kg/m2 or less)
  • long-term use of high-dose corticosteroid treatment (widely used for conditions such as arthritis and asthma), which can affect bone strength
  • heavy drinking and smoking
  • rheumatoid arthritis 
  • malabsorption problems, as experienced in coeliac disease and Crohn's disease
  • some drugs used in breast cancer and prostate cancer treatment which affect hormone levels
  • long periods of inactivity, such as long-term bed rest

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Last updated: 04 October 2011

Diagnosing osteoporosis

You may be diagnosed with osteoporosis because you have been identified as being at high risk and your doctor has referred you for a bone density or DXA scan.

Osteoporosis is most often diagnosed after the weakening of the bones has led to a fragility fracture. An X-ray cannot reliably measure bone density but is useful to identify fractures.

DXA scan

A bone density scan, called a dual energy X-ray absorptiometry (DXA) scan, is used to diagnose osteoporosis. It measures the density of your bones (bone mineral density or BMD) and compares this to the bone density of a healthy young adult. The difference between your measurement and that of a healthy young adult is known as a T score.

  • If your T score is between 0 and 1, you're considered to be within the normal range. 
  • A T score between -1 and -2.5 is classed as osteopenia, which is the name for the category of bone density between normal and osteoporosis. 
  • If your T score is below -2.5, you will be classed as having osteoporosis.

A bone density scan will diagnose osteoporosis, but having osteoporosis diagnosed or ruled out by a scan isn’t the only factor that determines your risk of fracture. Your doctor will take these factors into account before deciding whether treatment for osteoporosis is needed. The doctor will also pick the particular treatment depending on how safe and effective that drug is likely to be for you.

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Last updated: 04 October 2011

Treating osteoporosis

Treatment overview

Although a diagnosis of osteoporosis is based on the results of your bone mineral density (DXA) scan, the decision about what treatment, if any, you have can be based on a number of factors, including your risk of fracture. If you’ve been diagnosed with osteoporosis because you’ve had a fracture, you should still be treated to try to reduce the risk of any further fractures.

You may not need or want to take drugs to treat your osteoporosis. However, you should maintain good levels of calcium and vitamin D in your body. Your healthcare team may advise a change to your diet or taking supplements to do this.

Drugs for osteoporosis

There are a number of different drug treatments for osteoporosis. Your doctor will discuss the treatments available and will make sure that the medicines are right for you.

Bisphosphonates

Bisphosphonates work by slowing the rate at which the cells that break down bone (osteoclasts) work. This maintains bone density and reduces the risk of fracture. There are a number of different bisphosphonates, including alendronate, etidronate, ibandronate, risedronate and zolendronic acid. They are given as a tablet or as injection. 

The main side effects associated with bisphosphonates include irritation to the oesophagus, trouble swallowing and stomach pain, but not everyone will experience side effects. Osteoneocrosis of the jaw is a very rare side effect that has been linked with the use of bisphosphonates (more frequently with high-dose intravenous bisphosphonate treatment for cancer and not for osteoporosis). The cells in the bone of the jaw die, and this can lead to problems with healing. If you have a history of problems with your teeth, you may need a check-up before you start this treatment. If you have any concerns, speak to your doctor.

Strontium ranelate

Strontium ranelate appears to have an effect on both the cells that breakdown bone and the cells that create new bone (osteoblasts). It can be used as an alternative treatment if bisphosphonates are found not to be suitable. Strontium ranelate is taken as a powder dissolved in water.

The main side effects associated with strontium ranelate are nausea and diarrhoea. A few patients have reported a rare, severe allergic reaction to the treatment. If you develop a skin rash while taking strontium ralenate, stop taking it and speak to your doctor immediately.

Selective estrogen receptor modulators (SERMs)

SERMs are drugs that have a similar effect on bone as the hormone oestrogen. They help maintain bone density and reduce the risk of fracture, particularly at the spine. The only form of SERM available for the treatment of osteoporosis is raloxifene. Raloxifene is taken as a tablet every day.

Side effects that have been associated with raloxifene include hot flushes, leg cramps and a potential increased risk of blood clots.

Parathyroid hormone (PTH) (Teriparetide)

Parathyroid hormone is produced naturally in the body. It regulates the amount of calcium in bone. Parathyroid hormone treatments (human recombinant parathyroid hormone or teriparatide) are used to stimulate cells that create new bone (osteoblasts). They are given by injection. While other drugs can only slow down the rate of bone thinning, PTH can increase bone density. However, it is only used in a small number of people whose bone density is very low and where other treatments aren’t working.

Common side effects include nausea and vomiting. Parathyroid hormone treatments should only be prescribed by a specialist.

Calcium and vitamin D supplements

Calcium and vitamin D supplements can benefit older men and women and reduce their risk of hip fracture. Having enough calcium as part of a healthy balanced diet is important to maintain healthy bones. Aim to eat or drink 700mg of calcium each day. This is roughly equivalent to one pint of milk. If you are not getting enough calcium in your diet, ask your GP for advice about taking a calcium supplement. To have the right effect on your bones and help prevent falls or fracture, or in treatment of osteoporosis, you need the right dose of calcium (1.2g a day) and vitamin D (800 iu). These doses only occur in a small number of branded formulations prescribed by doctors, so any pills you buy over-the-counter may not have enough calcium and generally no vitamin D.

Hormone replacement therapy (HRT)

HRT is used for women going through the menopause as it can help to control symptoms. In addition, HRT has been shown to maintain bone density and reduce the risk of fracture during treatment. However, HRT is not specifically recommended as a treatment for osteoporosis and is now almost never used. This is because there is a risk that HRT slightly raises the chance of developing certain conditions, such as breast cancer, endometrial cancer, ovarian cancer and stroke, more than it lowers the risk of osteoporosis. Discuss the benefits and risks of HRT with your GP.

Calcitonin

Calcitonin is a hormone made by the thyroid gland. It inhibits the cells that break down bone (osteoclasts), which increases bone density. Calcitonin or salcatonin are taken as a nasal spray or an injection every day. Side effects include nausea, vomiting and diarrhoea.

Testosterone treatment

Testosterone treatment for men is useful when osteoporosis is due to an insufficient production of male sex hormones (hypogonadism).

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Last updated: 04 October 2011

Preventing osteoporosis

Your genes determine your potential height and the strength of your skeleton. However, lifestyle factors such as diet and exercise can influence how healthy your bones are. Following a healthy lifestyle throughout your life is the best way to delay the onset of osteoporosis and slow the rate at which your bones become fragile.

Regular exercise

Regular exercise is essential. Try to do a minimum of 30 minutes of exercise, at least three to four times a week. Weight-bearing exercise and resistance exercise are particularly important in improving bone density and helping prevent osteoporosis.

If you’ve been diagnosed with osteoporosis, it’s a good idea to talk to your GP or health specialist before you take up any new exercise activity, to make sure it’s right for you.

Weight-bearing exercises

Weight-bearing exercises are exercises where your feet and legs support your weight. High-impact weight-bearing exercises, such as running, skipping, dancing, aerobics and even jumping up and down on the spot, are all useful ways to strengthen your muscles, ligaments and joints. When exercising, wear footwear that provides your ankles and feet with adequate support, such as trainers or walking boots.

People over the age of 60 can also benefit from doing regular weight-bearing exercise. This can include brisk walking, keep-fit classes or a game of tennis. Swimming and cycling are not weight-bearing exercises.

Resistance exercises

Resistance exercises are exercises that use muscle strength, where the action of the tendons pulling on the bones boosts bone strength. Examples include press-ups, weight lifting or using weight equipment at a gym. If you have recently joined a gym or you have not been for a while, your gym will probably offer you an induction. This involves being shown how to use all the equipment and recommended exercise techniques. If you are unsure how to use a piece of equipment or how to do an exercise, ask a gym instructor for help.

Healthy eating

Eating a healthy, balanced diet is recommended for everyone. It can help prevent many conditions, including heart disease, diabetes and many forms of cancer, as well as osteoporosis.

Calcium is very important for maintaining strong bones. The recommended intake of calcium is at least 700mg a day. This is about equivalent to one pint of milk. Calcium can also be found in a number of different foods, including green leafy vegetables, dried fruit, tofu and yoghurt.

Vitamin D is also important for bones and teeth as it helps your body to absorb calcium. Vitamin D can be found in eggs, milk and oily fish. However, most vitamin D is made in the skin in response to sunlight. A short exposure to sunlight, without sunscreen (10 minutes twice a day) throughout the summer should provide you with enough vitamin D for the whole year.

Certain groups of people may be at risk of not getting enough vitamin D. These include people who may be housebound or particularly frail, people with a poor diet, people who keep covered up in the sunshine because they wear total sun block or adhere to a certain dress code, and women who are pregnant or breastfeeding. If you are at risk of not getting enough vitamin D through your diet or lifestyle, you can take a vitamin D supplement. For adults, 10 micrograms a day of vitamin D is recommended. The recommended amount for children is 7 micrograms for babies under six months, and 8.5 micrograms for children aged six months to three years. Talk to your GP for more information.

Other factors

Other lifestyle factors that can help prevent osteoporosis include:

  • quitting smoking: cigarette smoking is associated with an increased risk of osteoporosis
  • limiting your alcohol intake: the recommended daily limit is three to four units of alcohol for men and two to three units for women

 

Last updated: 04 October 2011