Page 3: Risk Factors for Breast Cancer

Each of us is born with a unique set of genes inherited from our families that makes us who we are. These distinct genes can affect who gets cancer and who does not. Although genetic risk is important, the National Cancer Institute (NCI) has reported that one in ten cases of breast cancer is caused primarily by gene defects we get from our parents. This means that 90% of breast cancer has environmental causes including lifestyle factors and exposure to agents in air and water. Although the exact mechanisms are currently unclear, scientists at the Center for Environmental Oncology of UPCI are conducting research to help us better understand the role of the environment in causing cancer.

Your environment can increase your chances of getting breast cancer. For example, your health can be affected by smoking, not exercising or eating unhealthy food. Exposure to ionizing radiation, radon or chemicals in your home and workplace (polluted air or water) may also increase your risk of breast cancer. Researchers at the NCI have reported that when a woman moves to the United States from other countries where the risk of breast cancer is lower, within a single generation her risk of developing the disease increases to that of a woman who was born in this country. This is why scientists at the World Health Organization and elsewhere believe that at least 80% to 90% of breast cancer cases have some environmental component.

• Cigarette smoke (including second-hand smoke)
• Drinking more than two drinks of alcohol every day
• Obesity and being overweight, especially after menopause
• Getting little or no exercise
• Diets high in well-done, smoked, preserved, fried or barbecued meats or fish
• Diets low in fruits and vegetables
• Exposure to chemicals found in:
  • polluted water and air
  • smoke: exhaust fumes from cars, trucks, and buses
  • combustion products formed from burning wood chips,
    rubber and when cooking meat or fish at high temperatures
  • some workplaces such as:
    • dry cleaning, nursing, medicine
    • hairdressers, barbers, truck/bus drivers

Personal risk factors associated with breast cancer include:

• Personal history of breast cancer (whether or not you've had breast cancer before)
• Your family history (whether aunts, mother, grandmothers on both sides of your family have had the disease)
• Gender (being a woman)
• Your age (being older than age 60)
• Use of hormone replacement therapy for more than a few months