Sex hormones, heart problems and diabetes in women
Some cancer treatments lower the amount of sex hormones in the body. The main female sex hormones are oestrogen and progesterone.
Low levels of these hormones may increase your risk of heart problems and diabetes.
Hormone therapy and the risk of heart problems
There is some evidence to suggest that aromatase inhibitors may increase the risk of heart problems. Aromatase inhibitors are a type of hormone therapy used to treat breast cancer.
The group of aromatase inhibitors includes:
- anastrozole (Arimidex)
- exemestane (Aromasin)
- letrozole (Femara)
Research into hormone therapies and heart problems
Evidence shows that before the natural menopause, oestrogen can offer some protection against heart disease.
Both the 
and treatment with hormone therapy lower the levels of hormones in the body. This can increase the risk of heart problems.
It is not certain why there is a higher risk of heart problems. Researchers think it may be because the hormone therapy increases the amount of cholesterol in the blood. This is a rare but serious side effect. And is especially important for people who already have heart problems.
Some research shows that the risk of heart problems is higher in women who take aromatase inhibitors.
Researchers are also looking into the possibility that tamoxifen may protect against heart problems. Tamoxifen is another type of hormone therapy used to treat breast cancer. It works by blocking the effect of oestrogen on cancer cells. It can also lower the level of fat lipids in the blood. High levels of fat can lead to heart disease. But we need more research to find out more about this.
Hormone therapy and the risk of diabetes
Diabetes is a condition that causes blood sugar levels to become too high.
Insulin is a hormone that controls the level of sugar (glucose) in your blood. There is evidence that hormone therapy can increase blood sugar levels. It can make your body resistant to insulin, which keeps your blood sugar high. Insulin is important in helping glucose to be absorbed by the cells in your body.
If you already have diabetes it may get worse if you have hormone therapy treatments. You may need to test your blood sugar level more often. You may also need to review your diabetic treatment with your doctor.
Your nurse or doctor will let you know more about the risk of diabetes.
Balancing the benefits of treatments against side effects
All treatments have side effects. Doctors balance the risk of side effects against the benefits of treating the cancer.
Tamoxifen can very occasionally cause serious side effects. This includes blood clots and womb cancer. Aromatase inhibitors cause a number of side effects, including bone weakening (osteoporosis).
Starting on one type of hormone therapy and then switching to another might reduce the side effects of both. We need more research to confirm how best to use hormone treatments.
It is important to remember that these hormone treatments reduce the risk of the cancer coming back. Or spreading to other parts of the body. Which is greater than the risk of heart problems and diabetes for most people.
Talk to your doctor if you already have heart problems or have a high cholesterol level and are worried.
Tips to help lower your risk of heart disease and diabetes
There are things you can do to help lower the risk of heart disease and diabetes.
- Maintain a healthy weight.
- Eat a healthy well balanced diet.
- Be physically active and exercise regularly.
Maintaining a healthy weight
There are many benefits to maintaining a healthy weight and having a balanced diet.
Be physically active and exercise regularly
Research has shown that exercise is safe and helpful for many people with cancer.
