More fat cells produce more estrogen. A high fat diet promotes an earlier menstrual cycle which leads to more estrogen exposure. Mice fed a high fat diet have offspring with a higher risk of breast cancer. In terms of quality, most of the fats we consume contain large amounts of organo-chlorides. Breast cancer cells have been demonstrated to grow in test tubes with these xenoestrogens.
Exercise directly decreases estradiol absorption, improves immune response and relieves stress.
Death of a loved one has been linked to an increased risk of breast cancer. The most validated risk factor for breast cancer is estradiol exposure. The more menstrual cycles, the more estradiol produced, the greater the risk. Late onset of menses, early menopause, pregnancy and lactation reduce the number of cycles and thus the risk. Women whose mothers had breast cancer are almost twice as likely to have it themselves.