Table of Contents
The following physical characteristics have been associated with increased risk:
- Obesity increases the risk for all types of estrogen receptor-positive breast cancers. Women who gain weight after menopause are most at risk. (On a positive note, losing weight after menopause decreases breast cancer risk.) In postmenopausal women, estrogen is produced in fat tissue. High amounts of fatty tissue increase levels of estrogen in the body, leading to faster growth of estrogen-sensitive cancers.
- Estrogen is involved in building bone mass. Therefore, women with heavy, dense bones are likely to have higher estrogen levels and to be at greater risk for breast cancer.
- Some studies have found a greater risk for breast cancer in taller women, possibly due to the higher estrogen levels associated with greater bone growth.
Environmental Factors
Exposure to Estrogen-like Industrial Chemicals. Chemicals with estrogen-like effects, called xenoestrogens, have been under suspicion for years. There has been particular concern with pesticides containing organochlorines (DDT and its metabolites, such as dieldrin) and pyrethroids (permethrin), but at this time evidence of any causal association is very weak.
Exposure to Diethylstilbestrol. Women who took diethylstilbestrol (DES) to prevent miscarriage have a slightly increased risk for breast cancer. There may also be a slightly increased risk for their daughters (commonly called "DES daughters"), who were exposed to the drug when their mothers took it during pregnancy.
Radiation Exposure. Heavy exposure to radiation is a significant risk factor for breast cancer. Girls who receive high-dose radiation therapy for cancer face an increased risk for breast cancer in adulthood. Low-dose radiation exposure before age 20 may increase the risk for women with BRCA genetic mutations.
Lifestyle Factors
Alcohol consumption is a risk factor for breast cancer, especially for women have two or more drinks a day.
Disproven Risk Factors
Antiperspirants or use of deodorants after shaving have not been linked with any higher risk for breast cancer. There is also no evidence that bras increase breast risk. Abortion does not increase risk.
Review Date: 11/08/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine,
Harvard Medical School; Physician, Massachusetts General Hospital.
Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M.,
Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
