Risk Factors: Breast Cancer

Content provided by the Faculty of the Harvard Medical School

Risk factors

A risk factor is something that makes you more susceptible to developing a disease compared with the general population. Age, for instance, is a risk factor for breast cancer. The older you get, the greater your risk of developing the disease. Family history is another risk factor. Risk factors do not necessarily mean that you will get cancer, however. Studies show that some women with many risk factors never develop breast cancer. At the same time, some women with no known breast cancer risk factors do.

Knowing the risk factors for breast cancer can help you take steps to lower your risk.

What are the risk factors?

Some risk factors are things you can't change, such as your age or family medical history. Others are within your control, such as diet and exercise. The major risk factors for breast cancer are:

• Gender

• Age

• Family medical history

• Ethnic/racial background

• Alcohol use

• Weight gain

• Sedentary lifestyle

• Toxic exposures

The Risk Factors That Can't Be Changed

• female sex

• aging

• family medical history

• mutations in BRCA1, BRCA2, and other genes

• ethnic/racial background

• first menstrual period age 12 or before

• menopause after age 55

• atypical tissue changes in the breast

• previous breast cancer

• previous radiation treatment

The Risk Factors That Can Be Controlled

• not having children or having children later in life

• use of postmenopausal hormone therapy

• alcohol consumption

• excess weight

• sedentary lifestyle

• smoking tobacco

Last updated:	April 23, 2007