Moderate Exercise Found To Reduce Breast Cancer RiskStudy Conducted In Postmenopausal Women< September 24, 2003 >Moderate, simple exercise reduces the risk of breast cancer in postmenopausal women, according to a study reported in the Journal of the American Medical Association. The report comes on the eve of national Breast Cancer Awareness Month observed in October. Researchers from the Fred Hutchinson Cancer Center in Seattle confirm earlier findings showing that exercise does indeed reduce the risk of breast cancer. But going one step farther, they also report that even moderate physical activity, such as 30 minutes of walking three times each week, offers substantial protection as well, something previous studies have not shown. "The important news here is that regular exercise allows a woman some measure of control over her personal risk profile for breast cancer," says study author Dr. Anne McTiernan, director of Fred Hutchinson's Prevention Center. "Plus, as long as the exercise is consistent, she doesn't even have to work that hard to get the benefits," says Dr. McTiernan. And, says Dr. McTiernan, the benefits of exercise extend to women at highest risk of the disease. "Women with a family history of breast cancer, those who never had children, and women using HRT (hormone replacement therapy) all saw a reduced risk of breast cancer in conjunction with exercise," Dr. McTiernan says. Dr. Steven Goldstein, a professor of obstetrics and gynecology at New York University Medical Center, says that while the study results are promising, they also warrant a few words of caution. "This is an observational study, and the women who experienced the protective effects of exercise might well have been women who generally took better care of themselves overall, thus reducing their risk factors in other ways," Dr. Goldstein says. So, while exercise confers many benefits - such as reducing risks of heart disease, high blood pressure, diabetes, and more - Dr. Goldstein also urges women not to abandon other important self-care measures. They include regular mammograms, monthly self-breast exams, reduced consumption of alcohol and fat, and no cigarettes. "Exercise, absolutely, but don't rely on that alone for breast health and protection," Dr. Goldstein says. The new study was based on data from the Women's Health Initiative (WHI), a major research project started in 1991 that follows tens of thousands of women in an effort to identify risk factors for various diseases including breast cancer. This particular arm of the study involved more than 74,000 postmenopausal women between the ages of 50 and 79, with a broad ethnic, racial, and geographic profile, from 40 testing sites nationwide. At the start of the study, each woman completed a survey documenting, among other health factors, her personal exercise history at ages 18, 35, and 50, as well as current level of activity. In a follow-up period of 4.7 years, the researchers documented 1,780 breast cancers. Dr. McTiernan and her group then investigated the exercise habits of these women, and compared them to those who did not develop breast cancer. The result: When compared to sedentary women, those who performed moderate exercise - such as walking or swimming - from 1.25 to 2.5 hours a week experienced an 18 percent decrease in the incidence of breast cancer. Those who exercised 10 hours or more a week saw only slightly more protection - up to a 22 percent decreased risk. Dr. McTiernan says risks were reduced even when various contributing factors for breast cancer were figured into the equation, such as smoking and drinking alcohol. The study also found those women who benefited most from exercise were the ones who had the least body fat. Dr. McTiernan reports that women with a body mass index (BMI) of 24 or less saw the greatest decreased risk of breast cancer - up to 32 percent - while those with a BMI of 28 or more saw no risk reduction. A body mass index greater than 25 is considered overweight; a BMI that exceeds 30 is termed obese. Currently, researchers are not sure how or why exercise exerts its protective effects against breast cancer. However, Dr. McTiernan hypothesizes that a reduction in body fat is the key. Studies have shown that excess fat cells help convert androgens and other hormones into excess estrogen, long suspected of having links to breast cancer. Dr. McTiernan also says that exercise reduces the amount of estrogen circulating in the blood, offering additional protection. Completing the circle, other studies have shown that exercise can also help keep insulin levels low, which, in turn, helps reduce body fat. Always consult your physician for more information. |
For more information on health and wellness, please visit health information modules on this Web site. Breast Cancer StatisticsBreast cancer is the most common cancer among women, excluding non-melanoma skin cancer. Currently, 3 million women in the US are living with the disease, including 2 million who have already been diagnosed, and another 1 million who do not yet know they have the disease. The American Cancer Society (ACS) estimates for 2003 include 211,300 new cases of invasive breast cancer being diagnosed in the US. In addition, ductal carcinoma in situ will be responsible for 55,700 new cases this year. In 2003, it is estimated that 1,300 men will be diagnosed with breast cancer. Year 2003 estimates include 40,200 deaths occurring from breast cancer in the US alone - this includes approximately 39,800 women and 400 men. Breast cancer is the leading cause of cancer death among women between the ages of 20 and 59 in the US. All women, regardless of family history, are at risk for breast cancer. In fact, in 90 percent of cases, there is no family history of the disease. Regardless of age, African-American women have the highest breast cancer mortality rates. Always consult your physician for a diagnosis. What Are Risk Factors?According to the National Cancer Institute (NCI), physicians cannot always explain why one person gets cancer and another does not. However, scientists have studied general patterns of cancer in the population to learn what factors may increase our chance of developing cancer. Anything that increases a person’s chance of developing a disease is called a risk factor; anything that decreases a person’s chance of developing a disease is called a protective factor. Some of the risk factors for cancer can be avoided, but many can not. Both smoking and inheriting specific genes could be considered risk factors for certain kinds of cancer, but only smoking can be avoided. The NCI states that prevention means avoiding the risk factors and increasing the protective factors that can be controlled so that the chance of developing cancer decreases. Although many risk factors can be avoided, it is important to keep in mind that avoiding risk factors does not guarantee that a person will not get cancer. Consult your physician about methods of preventing breast cancer that might be effective for you. Online Resources(Our Organization is not responsible for the content of Internet sites.) Centers for Disease Control and Prevention (CDC) National Institutes of Health (NIH) National Women's Health Information Center |
