1. What is osteoporosis?
Osteoporosis is a condition where your bones lose their strength and thickness (density). This leads to bones becoming weaker and more likely to break (fracture).
Bones have a thick outer shell and a strong inner mesh filled with collagen (protein), calcium salts and other minerals. The inside looks like a honeycomb, with blood vessels and bone marrow in the spaces between.
Osteoporosis means some of the outside and inside of the bone become thin. Sometimes the structure starts to break down causing wider spaces, and bones can fracture easily with little or no force.
Generally, osteoporosis causes no pain or symptoms, so often a person will not realise they have the condition until a fracture happens. The most common sites for a fracture are the wrist, hip and back (spine).
Although osteoporosis cannot be cured, treatments are available to try to keep the bones strong and less likely to fracture.
2. What causes osteoporosis?
Your risk of getting osteoporosis is increased by:
- Getting older
- Lower oestrogen levels
- Other factors such as your family and medical history
Our bones increase in density and strength until we reach our late 20s. Around the age of 35 we start to lose bone density as part of the natural ageing process. This happens gradually over time, but is much more significant for women after the menopause.
Low oestrogen levels
The hormone oestrogen protects against bone loss and helps to keep bones strong. Women who have gone through the menopause are at increased risk of osteoporosis and fractures because their ovaries no longer produce oestrogen, although small amounts of oestrogen are still produced by fat cells.
Women may also have low levels of oestrogen because of:
- An early natural menopause (before the age of 45)
- An oophorectomy (surgical removal of the ovaries)
- Treatment for cancer (such as chemotherapy, hormone therapy or ovarian suppression)
- Eating disorders such as anorexia nervosa or bulimia
Other risk factors
Other risk factors for osteoporosis and fractures include:
- A family history of osteoporosis or hip fractures
- Previous wrist, back (spine) or hip fracture that was not caused by injury
- Previous fracture after a fall from standing height or less (this may be a sign that the bones are weaker)
- Medical conditions such as Crohn’s disease, coeliac disease, ulcerative colitis, overactive thyroid (hyperthyroidism) and diabetes
- Medication (usually long-term use) including corticosteroid tablets (for conditions such as arthritis and asthma) and anticonvulsants (for conditions such as epilepsy)
- Some antidepressants
- Conditions that leave you immobile for a long time
- Low body weight
Certain lifestyle factors can make you more likely to have low bone density.
These include regularly drinking more than the recommended amount of alcohol, smoking, or a diet that is low in calcium and vitamin D.
3. Breast cancer treatments and bone health
Some breast cancer treatments can lower bone density and increase the risk of osteoporosis and fractures in both premenopausal women (women who have not gone through the menopause) and postmenopausal women (women who have gone through the menopause).
The likelihood of developing osteoporosis and having fractures will also depend on how healthy your bones were before your breast cancer treatment.
- Ovarian suppression
- Aromatase inhibitors (anastrozole, exemestane and letrozole)
Breast cancer treatment and osteoporosis
Following World Osteoporosis Day in 2019, we chatted live about what osteoporosis is, how breast cancer treatments can affect bone health and much more. Our Clinical Nurse Specialist, Jane was joined by Sarah Leyland, Osteoporosis Nurse Consultant at the Royal Osteoporosis Society.
Chemotherapy can affect the ovaries, causing an early menopause in some women. This means less oestrogen is produced, which can reduce bone density.
Women aged 45 or under whose periods have stopped for at least a year as a result of treatment may also be at risk of osteoporosis, even if their periods restart.
Some research has shown that postmenopausal women who have chemotherapy may have greater loss of bone density than they would have had without chemotherapy.
Ovarian suppression is when the ovaries are stopped from working (suppressed), either temporarily or permanently. This means there is less oestrogen in the body to help the cancer to grow. However, having less oestrogen in the body can also reduce bone density.
Tamoxifen blocks the effect of oestrogen on cancer cells.
Tamoxifen may slightly increase the risk of osteoporosis for premenopausal women. This is unlikely to lead to osteoporosis, unless ovarian suppression is given as well. However, your risk may be higher if you’re 45 or under and your periods have stopped for at least a year.
In postmenopausal women, taking tamoxifen slows down bone loss and can reduce the risk of osteoporosis.
Aromatase inhibitors (such as anastrozole, exemestane and letrozole) reduce the amount of oestrogen made in the body, which can reduce bone density and cause fractures.
They are usually used to treat breast cancer in postmenopausal women, but some premenopausal women take aromatase inhibitors at the same time as having ovarian suppression. Having these two treatments together can reduce bone density.
4. What is a DEXA scan and do I need one?
If your treatment team is concerned about your risk of developing osteoporosis and fractures, they may suggest a DEXA (dual energy x-ray absorptiometry) scan or DXA scan to check your bone strength before you start treatment.
The DEXA scan measures bone mineral density (BMD). BMD is the amount of calcium and other minerals in an area of bone and is a measurement of bone strength. The lower your BMD, the more likely osteoporosis will be diagnosed.
A DEXA scan uses a very small amount of radiation and is quick and painless. While you are lying down, an open x-ray scanner will pass over your body taking pictures of your hips and sometimes lower spine. Your results will include a T score. The T score measures how your BMD compares to a range of young healthy adults with average BMD.
The BMD score ranges:
- T score above -1 is normal
- T score between -1 and -2.5 is classified as osteopenia (see below)
- T score at or below -2.5 is defined as osteoporosis
Find out more about DEXA scans on the Royal Osteoporosis Society website.
If you are found to have osteoporosis, you will be advised about any appropriate drug treatment. You will also be given guidance on any changes to your diet or lifestyle that may be helpful.
Follow-up DEXA scans may be repeated after 2 to 5 years for some people. However, if you are taking an osteoporosis drug treatment and having no side effects and you have not had any fractures while taking it, then it is likely that the drug is working, and you will not need regular DEXA scans.
Your treatment team may follow guidance produced by NICE (National Institute for Health and Care Excellence) when deciding if you need a DEXA scan. However, this only applies to England. Assessment and treatment may be different in Wales, Scotland or Northern Ireland, your treatment team can tell you more about this.
5. What is osteopenia?
Some people’s results from the DEXA scan may show they have decreased bone density, but not enough to be classed as osteoporosis. This is called osteopenia.
If you have osteopenia, you may have a higher risk of fractures and some people will go on to develop osteoporosis. However, osteopenia does not always lead to osteoporosis. Osteopenia does not usually have any symptoms.
If you have osteopenia with no other risk factors you will be given advice about changes you can make to your lifestyle, such as diet and exercise. You may also be advised to stop or cut down smoking and limit your alcohol intake. You won’t usually need treatment.
If you have osteopenia and you are also taking an aromatase inhibitor you may be given treatment to reduce your risk of fracture. Your doctor will discuss this with you.
6. What is my fracture risk?
Research has shown that your risk of breaking a bone (fracture risk) can be assessed by including other risk factors. For example:
- Your age
- Family history of hip fractures
- Whether you have had a fracture in the past
When assessing your fracture risk, your doctor will take these factors into account as well as your BMD score. They may use an online fracture risk assessment tool such as FRAX or Qfracture to predict your risk of fracture over a period of time and help decide if you need treatment. These tools are designed for the general population and do not take into account breast cancer treatment.
Some people are more at risk of fracture than others. The lifestyle changes mentioned below and treatments to strengthen bones can reduce your risk.
Many fractures are the result of having a fall. If you are over 65 there is a self-assessment test to check if you are at risk of falling on the NHS website. You can discuss the result of this test and how best to manage your risk with your GP.
You can read their guide Get up and go - a guide to staying steady.
A cancer centre based in the US has also produced an online educational tool to promote bone health in people who have been treated for breast cancer.
7. Can osteoporosis be prevented or treated?
Looking after your bones
There are a range of ways to prevent and reduce further bone loss:
- Lifestyle changes to look after your bones
Although osteoporosis cannot be cured, treatments are available to try to stop the bones losing more bone density and to make them less likely to fracture. You will be advised about any appropriate drug treatment and its possible side effects. The Royal Osteoporosis Society has more information on drugs to prevent and treat osteoporosis.
Your GP may recommend a calcium and vitamin D supplement. You may be prescribed a tablet that contains both, such as Adcal D3.
Bisphosphonates are usually given to people who have had breast cancer to treat osteoporosis. This includes alendronate, zoledronic acid, risedronate and ibandronate.
Bisphosphonates help strengthen your bones and reduce your risk of fractures. They can be given as a tablet or as an injection into the vein. They may also be prescribed to protect your bones if you’re taking an aromatase inhibitor (such as exemestane, letrozole or anastrozole). Bisphosphonates may be used as a treatment to reduce the risk of primary breast cancer spreading. They are also sometimes given as a treatment for secondary breast cancer in the bone. This is not the same as having osteoporosis.
Denosumab is a drug that may be recommended to reduce the risk of fractures. It is given as an injection twice a year and slows down bone loss in osteoporosis. It’s a treatment for postmenopausal women who are unable to take certain bisphosphonates.
Raloxifene is given for the prevention and treatment of osteoporosis in postmenopausal women. Raloxifene is only prescribed for women who have had breast cancer after they have completed their breast cancer treatment.
Teriparatide is also prescribed for osteoporosis but is usually only recommended if you are unable have bisphosphonates or denosumab. It may be suggested if you have a very high risk of fracture, particularly of the spine.