Breast cancer risk factors

Although the direct cause of breast cancer is still unknown, certain risk factors increase your chances of having the disease.


Increasing age is one of the biggest risk factors for developing breast cancer.

Being female

Breast cancer is much more common in women than men.

Family history

Family history is important: if your mother, sister or daughter has had breast cancer you have a higher risk of having breast cancer, especially if they had it at an early age.

Genetic mutations

Two genes, named BRCA1 and BRCA2, have been identified which can play a part in breast cancer. Women who inherit specific mutations in either of these 2 genes have a much higher risk of getting breast cancer.

Starting periods early

Starting your periods before 12 years of age is a risk factor for breast cancer.

Starting menopause later

Starting menopause relatively late in life (after 55 years) is a risk factor for breast cancer.

Later or no pregnancies

If you have your first child after 35 years of age, or never have children, you will have a slightly higher risk of breast cancer.

Hormone replacement therapy

The benefits of taking combination hormone replacement therapy (progestogen and oestrogen) around the time of perimenopause for 1-5 years to treat menopause symptoms seem to outweigh the risks of breast cancer, however, taking HRT longer term, such as for 10 years, has been associated with an increased risk of breast cancer.

Previous breast cancer

If you have had breast cancer in one breast, you have a higher chance of developing breast cancer in the other breast.


Being obese increases your risk of breast cancer.

Alcohol consumption

Drinking alcohol increases the risk of breast cancer. The higher the alcohol consumption the greater the risk.

Radiation exposure

Having had radiation treatment to the chest as a child or young adult increases your risk of breast cancer.

Benign breast disease

Certain benign breast conditions such as atypical ductal hyperplasia or lobular carcinoma in situ can make getting breast cancer more likely.

What you can do

Ask your doctor what you can do to reduce your risk of breast cancer. Discuss when to start screening tests such as mammograms. Examine your breasts yourself every month to check for lumps or changes. Drink alcohol in moderation only and start exercising on most days of the week. Keep your weight at a healthy level. If you decide to use HRT, limit it to the lowest dose for the shortest time you can.

If you are at very high risk of breast cancer, for example because of inherited factors, you may wish to talk to your doctor about preventive medicines or surgery.

Last Reviewed: 29 July 2013


1. Mayo Clinic. Breast Cancer: Risk factors. Last updated May 2013. (accessed July 2013).
2. Cancer Council Australia. Breast cancer. Last updated July 2013. (accessed July 2013).
3. NHS Choices. Breast cancer (female) – information prescription. Causes and risk factors. Last updated July 2012. (accessed July 2013).


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