Risky History

Simply living longer is one of the strongest contributors to breast cancer, since age brings greater exposure to cancer-causing agents. Not the least of these is the female hormone estrogen, which can prompt breast tissue to grow abnormally after waxing and waning over a lifetime of menstrual cycles. But exactly how breast cells react to the hormone is influenced by genes. Two known genetic mutations, BRCA1 and BRCA2, have been identified, but other, still unknown genes almost certainly contribute to risk for the disease. The often cited risk factors are familiar to most people, but some may be more fiction than fact.

THINGS TO THINK ABOUT
Age: The older a woman is, the greater her lifetime exposure to potential carcinogens and cancer-promoting estrogen.
Genetics:About 10% of breast-cancer cases in the U.S. are due to inherited genetic mutations in the BRCA1 or BRCA2 genes.
Family Ties: Having two or more first-degree relatives with breast cancer could hint at unidentified genetic contributors to the disease.
Delayed Childbirth: Putting off pregnancy increases exposure to estrogen by increasing the total number of menses over a lifetime.

TENUOUS LINKS
Antiperspirants: Fears that blocked sweat glands cause tumors in the lymph nodes that connect to the breast are unfounded.
Birth Control: Oral contraceptives contain estrogen, but studies of their link to breast cancer have so far been inconclusive.
Smoking: Lighting up has to date not been found to increase breast-cancer risk, but tobacco is a known carcinogen.
Implants: Studies seem to show that implants — since they're not made of living tissue — do not increase breast-cancer risk.