Bone health

Our bones provide support and protect our organs. They store important minerals and contain bone marrow which is where our blood cells are made. It is important to keep bones healthy, especially as you get older.

Osteoporosis happens when your bones become weak. This means that you may be more likely to fracture a bone. There are various factors that can affect bone health:

  • age and gender
  • physical activity
  • diet
  • family history
  • fractures
  • weight
  • illness
  • drugs
  • smoking and drinking alcohol.

Some cancer treatments can cause your bones to become weaker. These include hormonal therapy, mainly for breast and prostate cancer; chemotherapy and steroids to treat leukaemia

If hormone levels are reduced this can lead to bone loss. For example, surgery to remove a man’s testicles or a woman’s ovaries (if she hasn’t already gone through the menopause) will cause hormone levels to be lowered.

Your doctor will talk to you about any treatments, which may lead to osteoporosis or bone loss before you have them.

The bones

The human body is made up of more than 200 bones of different shapes and sizes. They are made of collagen – a type of protein – calcium salts and other minerals. These make bones strong and rigid.

Long bones, for example in the legs and arms, are made up of a hard outer shell of compact bone. Each end of the bone is filled with cancellous or spongy bone. The middle of the bone is filled with bone marrow, which makes blood cells.

The structure of a long bone
The structure of a long bone

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Our bones:

  • provide support for our bodies, and the joints act as levers so that we can move around
  • protect various parts of our bodies from injury – for example, the ribs protect the heart and lungs
  • store important minerals, such as calcium, that are used by our bodies
  • provide a place for bone marrow which is where blood cells are made.

Our bones are constantly being broken down and replaced with new bone. This helps maintain their strength and shape. There are two main types of cells that break down and replace bone:

  • Osteoclasts break down and remove old bone.
  • Osteoblasts make new bone.

The joints at the end of bones are covered in cartilage. This is a tough, flexible material, like gristle. Because cartilage is more elastic than bone, it allows the bones to move freely at the joints. It also cushions the bones at the joints, to stop them rubbing against each other.

Why bone health is important

Bone health is important throughout your life, but it’s even more important as you get older. As you age, bone loss gradually increases, which means the bones get weaker. As this happens, some people may develop osteopenia or osteoporosis:


This happens when your bones become slightly less dense. It can sometimes develop into osteoporosis.


This happens when your bones become even less dense and weaker. Weaker bones are more prone to breaks (fractures).

A healthy bone [L]; A bone with osteoporosis [R]
A healthy bone [L]; A bone with osteoporosis [R]

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Osteoporosis isn’t painful. It doesn’t cause any symptoms until a weakened bone fractures (breaks). People with osteoporosis are more likely to have a fracture than other people. Fractures usually happen in the wrists, hips and spine, but may also happen in other bones. A fracture can make movement painful and difficult.

People over the age of 50 are more likely to develop a fracture due to poor bone health. About 1 in 3 women (33%) and 1 in 5 men (20%) over 50 will have a fracture. Younger people can also develop fractures due to weak bones. People who have cancer treatments – particularly some types of hormonal therapy – are more likely to develop osteoporosis and fractures.

A lot can be done to prevent bone loss and osteoporosis. Your doctor can do tests to assess the health of your bones. The results of these tests help doctors decide whether you need treatment to lower your risk of a fracture.

Factors affecting your bones

A number of factors affect bone health. These include:

Age and gender

Your bones are strongest when you are in your twenties. After this, bones gradually become more fragile and likely to fracture the older you get.

Women lose bone more quickly after the menopause. This is because the level of the hormone oestrogen, which helps keep bones healthy, falls at the menopause.

Physical activity

Physical activity makes your bones stronger. Regular daily exercise is one of the best ways to improve and maintain your bone strength. Weight bearing exercises, such as walking, climbing stairs or dancing, are particularly helpful.


Eating a balanced diet helps keep bones healthy. Getting enough calcium and vitamin D helps build bones and keep them strong.

Family history of osteoporosis

If you have a family history of osteoporosis, you’re more at risk of developing it yourself. If one of your parents had a hip fracture you’re more at risk of having a hip fracture yourself.


People who have weak bones due to osteoporosis are more likely to develop fragility fractures. These occur after a fall from standing height or lower. People who have healthy bones are less likely to break a bone from a fall at this height.


Being underweight or having a Body Mass Index (BMI) below 19kg/m2 can increase your risk of fracture and bone loss. BMI is a measure of healthy weight. It’s based on your height and weight. Your GP, or practice nurse can work out your BMI for you. Alternatively, a BMI calculator is available on the NHS Choices website.


Some illnesses can reduce your bone health. These include:

  • rheumatoid arthritis
  • inflammatory bowel diseases such as crohn’s disease and ulcerative colitis
  • diseases of the lung and liver
  • thyroid diseases such as having an overactive thyroid gland
  • eating disorders such as anorexia nervosa
  • illnesses that cause disability and make a person less mobile.

If you’re a woman and have an early (premature) menopause this can also reduce your bone health.


Some drugs, if taken for a long time, may increase your risk of developing osteoporosis. These drugs include the following:

  • Steroids – these are given to treat a number of illnesses such as rheumatoid arthritis and asthma. They may also be used in some cancer treatments.
  • Some antiepileptics – such as phenytoin. Anti-epileptics are used mainly in the treatment of epilepsy to help prevent fits (seizures).

Smoking and drinking alcohol

Several studies have shown that smoking reduces bone density and weakens bones.

Drinking more than three units of alcohol a day also affects the bones and increases the risk of fractures. Being drunk may also make falls more likely, which can cause fractures. People who drink a lot of alcohol also often have a poor diet. If their calcium intake is reduced, this can lead to bone loss and weaker bones.

Cancer treatments and bone health

Some cancer treatments can increase the risk of bone loss and osteoporosis.

Hormonal therapy

Hormonal therapy for breast cancer

Drugs called aromatase inhibitors are commonly used to treat women with breast cancer who have been through the menopause. These drugs include: anastrazole (Arimidex®), exemestane (Aromasin®) and letrozole (Femara®). They can cause bone loss in some women and may increase the risk of fractures.

Another drug called goserelin (Zoladex®) may be given to premenopausal women with breast cancer who haven’t been through the menopause. It works by reducing oestrogen levels. Goserelin may also cause bone loss.

‘My cancer is hormone-positive so I’ve been on Zoladex and Arimidex, and this has resulted in my bone density being much lower than average for my age. When I switched on to these drugs I got very stiff and achy, but regular exercise has helped alleviate my symptoms a great deal.’


Hormonal therapy for prostate cancer

Some drugs that treat prostate cancer reduce the level of testosterone. They include Zoladex, leuprorelin (Prostap®) and triptorelin (Decapeptyl®, Gonapeptyl Depot®). A side effect of these drugs is bone loss.

Chemotherapy drugs

Some chemotherapy drugs stop the ovaries or testicles working. When this happens, they no longer produce normal levels of the hormones oestrogen (in women) or testosterone (in men). This effect can be temporary or permanent. Changes to hormone levels in people below the age of 50 can result in bone loss. Your healthcare team will tell you if your chemotherapy drugs are likely to affect your hormone levels.

Other chemotherapy drugs, such as methotrexate and ifosfamide, may weaken bones. If you need these drugs your doctor or nurse will talk to you about this.

Other cancer treatments

Other drugs used in cancer treatments may be linked with changes in bone density. These include imatinib (Glivec®), which is used to treat chronic myeloid leukaemia (CML), advanced myeloma and some gastrointestinal tumours.

Some people with certain types of leukaemia or lymphoma have steroids as part of their treatment. Long-term use of steroids (eg prednisolone or dexamethasone) can cause bone loss and increase the risk of fractures.


Hormone levels are reduced if:

  • a man has an operation to remove his testicles
  • a woman who hasn’t gone through the menopause has surgery to remove her ovaries.

The reduced hormone levels can lead to bone loss.

Back to Bone health

Looking after your bones

There are changes that you can make to your diet and way of life to improve your bone health.