Breast cancer is a major problem for Hispanic women, but exercise may be a key to reducing the number of those women who get breast cancer and die from it, according to a report in the American Journal of Epidemiology (Vol. 154, No. 5: 442-450).

Although they have a lower incidence than non-Hispanic white women, breast cancer is still the most common cancer affecting Hispanic women.

Many studies have been conducted on how to reduce a woman’s risk from breast cancer, some of which have suggested that vigorous exercise is one way to do it. But these have been done mostly in non-Hispanic white women. Now a new report shows that exercise can also prevent breast cancer in Hispanic women and may be even more protective than it is for non-Hispanic white women.

To better understand how to prevent this increase, Frank Gilliland, MD, PhD, and his colleagues at the University of Southern California Health Sciences Center looked at how exercise affects the risk of breast cancer in Hispanic women. Their study reviewed the exercise habits of Hispanic women with and without breast cancer living in New Mexico. The researchers compared the exercise activity of 332 Hispanic women with breast cancer to 388 Hispanic women without the disease. They also looked at the role of exercise in breast cancer risk in non-Hispanic white women.

The women were asked to indicate the activities they had done on a regular basis for at least the last six months. The doctors were interested in activities such as walking/hiking, jogging/running, swimming, biking, exercise classes, and sports participation. They also asked about factors that might influence a woman’s risk of breast cancer such as diet, menstrual history, number of pregnancies, breast-feeding, hormone use, family history of breast cancer, and other factors so they could correct for any differences.

When the researchers tabulated their results, they found that Hispanic women who exercised vigorously had a lower rate of breast cancer by anywhere from 30% to 70%, depending on how vigorously they worked out. To get to the lowest breast cancer risk (30%), for example, women would have to jog at a six mile per hour rate for more than five hours a week or walk briskly for one and one-half hours daily. This occurred regardless of whether or not they were overweight.

Past research on non-Hispanic white women had found that exercise lowered the risk of breast cancer only in postmenopausal women. The results in the non-Hispanic white women in this study confirmed this. Only the postmenopausal non-Hispanic white women benefited from vigorous exercise.

But in Hispanics, exercise benefited both premenopausal and postmenopausal women. Though this report is not the final word and more studies are needed, it represents good news for Hispanic women because it shows the way to reduce their risk of breast cancer. The need for vigorous exercise, however, may prove challenging.

The American Cancer Society (ACS) estimates that in the United States in 2001, 192,200 women will be diagnosed with breast cancer and 40,200 women will die of this disease. For further information see the ACS document on breast cancer on this web site.