What are breast cancer risk factors?

• Age: The chances of breast cancer increase as you get older.
• Family history: The risk of breast cancer is higher among women who have relatives with the disease. Having a close relative with the disease (sister, mother, daughter) doubles a woman's risk.
• Personal history: Having been diagnosed with breast cancer in one breast increases the risk of cancer in the other breast or the chance of an additional cancer in the original breast.
• Women diagnosed with certain benign breast conditions have an increased risk of breast cancer. These include atypical hyperplasia, a condition in which there is abnormal proliferation of breast cells but no cancer has developed.
• Menstruation Women who started their menstrual cycle at a younger age (before 12) or went through  menopause later (after 55) have a slightly increased risk.
• Breast tissue: Women with dense breast tissue (as documented by mammogram) have a higher risk of breast cancer.
• Race: White women have a higher risk of developing breast cancer, but African-American women tend to have more aggressive tumors when they do develop breast cancer.
• Exposure to previous chest radiation or use of diethylstilbestrol increases the risk of breast cancer.
• Having no children or the first child after age 30 increases the risk of breast cancer.
• Breastfeeding for one and a half to two years might slightly lower the risk of breast cancer.
• Being overweight or obese increases the risk of breast cancer.
• Use of oral contraceptives in the last 10 years increases the risk of breast cancer.
• Using combined hormone therapy after menopause increases the risk of breast cancer.
• Alcohol use increases the risk of breast cancer, and this seems to be proportional to the amount of alcohol used.
• Exercise seems to lower the risk of breast cancer.

 Reviewed by Melissa Conrad Stöppler, MD on 10/10/2011