The last decade was filled with research about what actually causes breast cancer. Early studies sparked still widely-believed rumors and proven factors often go ignored.

To keep you in the know about breast cancer, we’ve compiled a list of proven risk factors and some debunked myths about breast cancer causes. Get informed about the very real risks and the somewhat baseless precautions, so you can hopefully stay cancer free.

  1. DNA Mutations

The most clear and obvious cause of breast cancer is genetic DNA mutations that are inherited from previous generations. Mutations such as BRCA1 and BRCA2 can increase your risk of breast cancer.

If you have a family history of breast cancer, you should let your doctor know and discuss your potential risk and ways you can stay healthy.

  1. Exposure to Radiation

Women who were exposed to radiation treatments in the chest area as a child or young adult have a greatly increased risk of breast cancer. This exposure is often due to the treatment of another cancer.

Talk to your doctor if you worry about having received radiation exposure at a young age.

  1. Menstrual Periods

Women who began their periods before age 12 and women who go through menopause after age 55 have a slightly increased risk of breast cancer. Women over age 40 should perform regular self-breast exams and receive mammograms to ensure their health, especially as they go through menopause.

  1. Not Having Children or Breastfeeding

Women who choose not to have children or have children after the age of 35 have an increased risk of breast cancer. Although this increase is slight, it is present. Conversely, women who have been pregnant many times or were pregnant when younger have a reduced risk of breast cancer.

Additionally, not breastfeeding has been related to an increased risk of breast cancer in some studies. On the other hand, women who breastfeed, especially for a year-and-a-half to two years, have a decreased risk of breast cancer.

  1. Certain Birth Control Methods

Studies have shown that women who use birth control pills or a certain injectable form of progestin-only birth control may have a slightly greater risk of breast cancer than women who have never used them.

The studies also show, however, that this risk seems to go back to normal once use of those forms of birth control have stopped.

  1. Alcohol

It has been proven time and time again that the use of alcohol increases breast cancer risk. And this is not only in the case of excessive drinking. In fact, as little as one drink a day can increase a woman’s risk.

  1. Overweight or Obese

Being overweight or obese comes with a number of health risks, and breast cancer is one of them. This risk increases if the woman is overweight or obese after menopause. The later in life that women gain weight, the worse the risk of breast cancer seems to be.

  1. Dense Breast Tissue

Dense breast tissue has been shown to increase risk of breast cancer and make lumps more difficult to detect. To combat this issue, several states have passed laws that require physicians to disclose to women if their mammogram indicates that they have dense breasts.

Ask your physician if you have dense breasts during your next exam and learn what the implications are if you do.

  1. Race

Overall, white women are slightly more likely to develop breast cancer than African-American women. However, research has shown that African-American women have a higher risk of dying from breast cancer.

  1. Hormone Therapy After Menopause

Combined hormone therapy after menopause, which involves taking estrogen and progesterone, has been shown to increase the risk of getting breast cancer. However, like birth control, this risk seems to go back to normal over time after the hormone treatment has stopped.

If you are going through menopause, this is something you should discuss with your doctor.

Things That Likely Do Not Cause Cancer

Several studies have attempted to link all kinds of potential causes to breast cancer. Many of these have shown less clear connections or have been disproven entirely.

  1. Antiperspirants
  2. Bras
  3. Caffeine
  4. Microwaves
  5. Cell Phones
  6. Most Chemicals


The best thing you can do to reduce your risk of breast cancer is to stay informed. Understand the risk factors in your life and communicate with your physician regularly about your concerns.

Spend Breast Cancer Awareness Month spreading the word about breast cancer risks and good practices to your friends and family, and help promote a cancer-free community.