Risk Factors

The best opportunities for reducing breast cancer risk are eating a healthy diet and being physically active throughout life (thereby maintaining a healthy body weight), minimizing alcohol consumption and avoiding tobacco as well as nonessential hormones.

Known Risk Factors

• Gender: More than 99% of breast cancers occur in women
• Age: risk increases as you get older
• Early menstruation (before the age of 12)
• Late menopause (after age 55)
• Having a first baby after age 30 or never having a baby
• Having a close relative with breast cancer
• Being physically inactive
• Being overweight or obese – especially after menopause
• Taking hormone replacement therapy

Possible Risk Factors

• Eating too few fruits and vegetables
• Drinking too much alcohol
• Never breastfeeding Click here to learn more about breastfeeding
• Smoking tobacco or being exposed to second-hand smoke
• Using birth control pills
• High levels of radiation exposure to the chest
• Genetic Risk Factors

While all cancers are caused by the disruption of genes, we know that approximately 5 to 10% of cancers are related to specific inherited genetic abnormalities.

There are scientific methods to identify some of these inherited defects to determine whether some people have an increased chance of developing certain types of cancer. These cancers happen more often in some families than in others.

For more information about genetic risk/genetic factors, visit the Canadian Cancer Society.

Causes

Also see the Causes of Breast Cancer

Minimize Your Risk

Learn how to minimize your risk