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Heart problems and diabetes and sex hormones

This page has information about how some hormone therapies can cause heart problems and diabetes for some people. There is information about


Sex hormones and heart disease and diabetes

Some cancer treatments lower the amount of sex hormones in the body. The sex hormones are oestrogen and progesterone in women and testosterone in men. Research suggests that low levels of testosterone can cause heart problems and diabetes in men. And there is some evidence to suggest that hormone treatments for breast cancer called aromatase inhibitors may cause heart problems in women.

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Men and heart problems and diabetes

There is increasing evidence to suggest that heart disease and diabetes can develop in some men having hormone treatment for prostate cancer.

Heart problems and diabetes may develop because the hormone treatment lowers testosterone levels and causes

  • Men to gain weight – especially around the tummy (abdomen)
  • An increase in the amount of fats called cholesterol in the blood
  • A resistance to insulin in the body so that you need to make more insulin

For men who already have heart problems or diabetes, hormone treatment can make these conditions worse. If you have diabetes you may need to check your blood sugar level more often. You may also need to increase the amount of insulin you have.

If you have heart problems, your heart specialist may need to check your heart medicines before you start hormone therapy. All men have regular blood tests to check the level of cholesterol in the blood during their treatment.

Much of the research into heart problems and diabetes has looked at men who are over 65 years of age. Older people tend to be more at risk of these conditions than younger men. Researchers suggest that GPs should do regular check ups for heart disease and diabetes in men having hormone treatment for prostate cancer.

We need more research to understand exactly how and why these problems develop. Then we can develop treatments that can treat the problems or prevent them from happening.

Read about hormone treatment for prostate cancer.


Women and heart problems

Research suggests that women who take hormone therapies called aromatase inhibitors may be at a slightly higher risk of heart problems. The group of aromatase inhibitors includes the drugs anastrozole (Arimidex), exemestane (Aromasin) and letrozole (Femara).

It is not certain why there is a higher risk of heart problems in these women. 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 women who already have heart problems.

Some research shows that the risk of heart problems is higher in women who take an aromatase inhibitor for 5 years. The risk may be lower for women who switch from one type of hormone treatment to another. For example, researchers found that women who took the hormone therapy tamoxifen for 2 or 3 years and then switched to an aromatase inhibitor for a few years did not have a higher risk of heart problems.

All treatments have side effects. Doctors balance the risk of side effects against the benefit of the treatment in treating the cancer. Tamoxifen can very occasionally cause serious side effects including blood clots and womb cancer. Aromatase inhibitors cause a number of side effects including bone weakening (osteoporosis).

It may be that starting on one type of hormone therapy and then switching to another could reduce the side effects of both. We need more research to confirm how best to use hormone treatments for breast cancer. Researchers are looking into the possibility that tamoxifen may protect against heart problems. Tamoxifen can lower the level of fat lipids in the blood. High levels of fat can lead to heart disease. But there is no research yet to say that tamoxifen does protect from heart disease. 

It is important to remember that these hormone treatments reduce the risk of the cancer coming back. The risk of the cancer coming back is greater than the risk of heart problems for most people. If you already have heart problems or have a high cholesterol level and are worried about this you can talk to your cancer specialist.

Read about 

Hormone treatments for breast cancer

Tamoxifen, anastrozole, exemestane and letrozole.


What you can do

You can lower your risk of developing heart disease and diabetes by

  • Maintaining a healthy weight
  • Eating a healthy well balanced diet
  • Taking regular exercise

If you don’t normally take regular exercise, you should talk to your doctor or specialist nurse before you start. They can help you to work out what is best for you. This is particularly important if you have high cholesterol or were overweight before you started your cancer treatment.

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Updated: 29 June 2015