Factors inside and outside of the body can affect breast cancer risks and outcomes. Those outside the body are often called environmental factors. There is no one scientific definition for what is considered an environmental factor, and different scientists may use different categories when deciding whether a risk factor is environmental.
Environmental factors include many things found in nature that we eat, drink, touch or breathe, as well as man-made factors. They can include chemicals or pollutants, radiation, microorganisms (infections), or lifestyle factors such as diet, exercise or smoking. Even medications, such as birth control pills or menopause hormone therapy, can be considered environmental factors. Some environmental exposures are passive, such as sunlight (ultraviolet rays) and air pollution. Others are active, such as eating a healthy diet.
Identifying which environmental factors keep us healthy and which can increase the risk of breast cancer is an important part of understanding breast cancer risk and survival.
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