Breast Cancer Risk Factors
At a Glance
These factors can increase or decrease breast cancer risk. The protective factors can actually reduce breast cancer risk.
Factors that influence breast cancer risk include:
- Lifestyle factors like diet and exercise
- Systemic factors like race, power, and inequities
- Chemical and radiation exposures (see our Glossary of Exposures for more)
- Genetics
See pullouts from Paths to Prevention: the California Breast Cancer Primary Prevention Plan for the science on each breast cancer risk factor.
Chemicals in Consumer Products
- Starting in utero, we are exposed to harmful chemicals from consumer products
Diet and Nutrition
- Healthy dietary patterns may be protective against breast cancer.
Genetics
- 5-10% of breast cancers are attributed to genetic history
Ionizing Radiation
- Medical diagnostic procedures such as CT scans and X-rays
Light at Night
- Nightshift work is a probable human carcinogen
Non-Ionizing Radiation
- Cell phone evidence mixed
- Risk from electric power transmission line close proximity
Occupation
- Chronic chemical exposure in the workplace
Pharmaceutical Hormones
- Some Hormone replacement therapy (HRT) treatments are known carcinogens
Lack of Physical Activity
- Physical activity is protective against breast cancer
Place-based Chemical Exposures
- Highway pollution, industrial facilities, and trash disposal sites
Pregnancy-related Factors
- Age, number of births, and breastfeeding can all impact risk
Related Science
Paths to Prevention: the California Breast Cancer Primary Prevention Plan
Read the comprehensive CA action plan to stem rising breast cancer rates.
Glossary of Exposures
Exposures with the strongest evidence linked to breast cancer
Types: Article, Fact Sheet, Link, Report
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