Both genetic and environmental factors are believed to play a role in a woman's risk of developing breast cancer. Additional factors that may increase risks of breast cancer include pesticide and other chemical exposures, alcohol consumption, induced abortion, high-fat diet, and physical inactivity. A majority of women have one or more risk factors for breast cancer. However, most risks are at such a low level that they only partly explain the high frequency of the disease in the population. Woman with none of the known risk factors can still get breast cancer.
All women are at risk.
To date, knowledge about risk factors hasn't translated into practical ways to prevent breast cancer. Since adult women may not be able to alter their personal risk factors in any practical sense, the best way opportunity for reducing mortality is through early detection.