As National Breast Cancer Awareness Month draws to a close, most of the focus in the media has been on early detection of the disease, and treatment once a breast tumor is found. But what about prevention of breast cancer in the first place? Is there anything women can do to reduce their risk, or should we resign ourselves to the fact that 1 in 8 of us will develop breast cancer in our lifetimes?

It turns out there are some things girls and women can do that may decrease their chance of developing breast cancer. Most of these recommendations target the fact that breast cancer can develop when estrogen levels in the body are high.

Estrogen is one of the female hormones, naturally made by the ovaries. It is also produced by excess fat in the body. It can be introduced to the body by estrogen-containing medications and supplements, and is found in meat and dairy products as well.

• First, maintain a healthy weight. If you are overweight after menopause, your risk of breast cancer is significantly higher than women of average weight. Since estrogen is produced by fat tissue in the body, the more body fat you have, the higher your estrogen level.

• Second, limit your alcohol intake. If you drink one alcoholic beverage every day, your risk of breast cancer goes up 9 percent. Compared to women who do not drink, women who drink two to four alcoholic drinks per day have a 40 percent higher risk.

• Third, stay physically active, starting in childhood. Girls who are physically active start menstruating later than inactive girls, so they produce less estrogen at a young age. Women who are physically active are more likely to maintain a normal weight. Also, exercise and physical fitness improves the immune system, which may help kill or slow the growth rate of cancerous cells.

• Fourth, avoid taking estrogens after menopause. Hormone replacement therapy (HRT) using estrogen alone or an estrogen-progestin combination has been found to increase risk of breast cancer. If HRT is needed for the treatment of significant menopausal symptoms such as hot flashes and mood swings, it should be taken at the lowest effective dose, for the shortest time needed.

In addition to these recommendations, which are the most scientifically valid and well-studied according to the National Cancer Institute, there are other factors that play into breast cancer risk.

Women who have children at a young age and breastfeed their children have a lower risk than women who don't have children or who don't have children until after age 35.

Much recent debate has focused on the role of chemical toxins in the environment and their link to many types of cancer. A few studies have found that exposure to some organochlorine compounds (such as PCBs and dieldrin) increase breast cancer risk; other studies have not found a link.

The link between the use of birth control pills (which contain both estrogen and progestin) and breast cancer is not completely clear; studies have come to conflicting results. We know that birth control pills prevent unintended pregnancies as well as significantly reduce the risk of ovarian and endometrial cancers. Many experts believe there is only a slightly increased risk of breast cancer for women on low-estrogen pills (20 to 35 mcg estrogen per pill).

Women with a strong family history of breast cancer should read about or talk to their health care provider about the pros and cons of being tested for the BRCA gene alteration, which causes breast cancer and runs in families.

Kathryn B. Brown is a family nurse practitioner with a master's degree in nursing from OHSU. Is there a health topic you would like to read about? Send ideas to You can find more local health news and information in the Health section at

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