Risk Factors for Breast Cancer

Known Risk Factors

All women are at risk for breast cancer; the biggest risk factors are being a woman and aging. Other risk factors include:

• Personal or family history of breast cancer.
• History of noncancerous breast disease (diagnosed as proliferative breast disease).
• Having early onset of menstrual periods or late menopause.
• Recent use of oral contraceptives or postmenopausal estrogens.
• Never having children or having first child after age 30.
• Chest radiation therapy as a child or young adult.
• Consuming two or more alcoholic drinks a day.
• Obesity, especially after menopause.
• Mutations of the BRCA1 and BRCA2 genes.

New Investigations Into Potential Risk Factors

Spontaneous or induced abortion

Although several studies have suggested that having a spontaneous or induced abortion may increase the risk of breast cancer, other studies have not found such an association. Reviews of the literature and a recent prospective study suggest that the risk of breast cancer probably is not related to termination of a pregnancy. However, results from additional prospective studies are needed before scientists can make conclusions about the influence of abortion on breast cancer risk.

Silicone breast implants

In a recent report from the Institute of Medicine, an expert committee concluded that silicone breast implants do not cause breast cancer, its recurrence, or any other major disease in women. This clear conclusion followed two years of review of thousands of scientific reports, undertaken at the request of the US House of Representatives and the federal Department of Health and Human Services.

Diet

The relationship between breast cancer risk and diet continues to be investigated. Scientists are evaluating the possible beneficial effects of fiber, fresh fruits and vegetables, and vitamins, including folic acid in adolescence, as well as the potential elevated risks from diets high in fat, protein, or total caloric intake. A recent comprehensive review of the literature regarding the potential association between these various dietary factors and breast cancer risk concluded that while it was probable that diet is involved in breast cancer etiology, results of investigations are certainly conflicting, and the nature of any relationships remain unproven.

Pesticide exposure

Environmental exposure to chemical pesticides has aroused considerable interest due to the persistence of these chemicals in the environment and in human fat, as well as the potential of some pesticides, such as DDT, to promote tumors in animal studies, and to mimic naturally occurring estrogens. However, the results of epidemiologic studies in this important area of research have been conflicting. Research in this area continues.

Source: American Cancer Society, Inc.