Environmental Factors Associated with Breast Cancer

A recent report says that "Lifestyle Changes Prevent One-Third of Cancers", and that fewer than 10 percent of breast cancer cases are inherited (33rd Annual San Antonio Breast Cancer Symposium, 12/7/2011).

Anything that increases a woman's exposure to estrogen also increases her risk for breast cancer, a disease that affects one in eight women:

• being overweight: Full fat cells make estrogen, so overweight women have more estrogen
• not exercising: lack of exercise increases risk for obesity
• drinking alcohol
• taking birth control pills
• taking estrogen and progesterone pills at any age
• starting periods before age 11
• starting menopause after age 55
• never being pregnant (thus more menstrual cycles)
• never breast feeding

Radiation from too many medical tests also increases breast cancer risk. Three abdominal CT scans give as much radiation as atomic bomb survivors received. Possible, but unproven, causes of breast cancer include: smoking, second-hand smoke, nighttime shift work, exposure to benzene and other chemicals, or to BPA and certain other plastics ingredients.

There is no evidence that breast cancer is caused by hair dyes or by radiation from cellphones, microwaves or other electronic gadgets.

WHY DOCTORS PRESCRIBE PROGESTERONE: Taking progesterone and estrogen markedly increases breast cancer risk. Estrogen stimulates the inner lining of the uterus to grow, and uncontrolled growth is cancer. Taking estrogen can cause uterine cancer, while progesterone stops estrogen from stimulating the uterus. So, to prevent uterine cancer, doctors usually prescribe progesterone with estrogen to any woman who still has a uterus. However, taking both estrogen and progesterone increases breast cancer risk. Many doctors now recommend no hormone therapy for women at menopause.