Breast cancer risk contributors
Here are factors that the National Cancer Institute and the American Cancer Society list as carrying an increased risk for breast cancer.

Factors governed by lifestyle:

  • Not having children or having them later in life: Women who have not had children, or who had their first child after age 30, have a slightly higher risk. Being pregnant more than once and at an early age reduces breast cancer risk.
  • Alcohol use: Those who have two to five drinks daily have about 1½ times the risk of women who drink no alcohol. The ACS suggests stopping at one drink a day.
  • Recent use of birth control pills
  • Postmenopausal hormone therapy (PHT)
  • Not breast-feeding
  • Being overweight or obese
  • Lack of exercise
  • Factors you can't change:
  • Gender
  • Age: The chance of getting breast cancer goes up as a woman gets older. About 2 out of 3 women with invasive breast cancer are 55 years or older when the cancer is found, ACS says.
  • Genetic risk factors: About 5 to 10 percent of breast cancers are thought to be linked to inherited gene mutations. The most common are the BRCA1 and BRCA2 (breast cancer 1 and 2) genes. Women with these gene changes have up to an 80 percent chance of getting breast cancer.
  • Family history: Breast cancer risk is higher among women whose close blood relatives have this disease.
  • Personal history of breast cancer: A woman with cancer in one breast has a greater chance of getting a new cancer in the other breast or in another part of the same breast.
  • Race: White women are slightly more likely to get breast cancer than are African-American, Hispanic or Asian women.
  • Dense breast tissue
  • Menstrual periods before 12 or menopause after 55
  • Breast radiation before age 30
  • Treatment with DES (diethylstilbestrol)