A new study indicates that many women with a family history of breast cancer are obese or sedentary, both of which may further boost their risk of the disease.

In surveys of 92 women with a family history of breast cancer, UK researchers found that the majority were overweight, with 37 percent being obese. This was despite the fact that most - including three-quarters of the overweight women - recognized obesity as a risk factor for breast cancer.

What’s more, few women were getting enough exercise, the researchers report in the journal International Seminars in Surgical Oncology.

Of 59 postmenopausal women in the study, only 15 percent said they exercised for at least four hours per week.

Because women with a family history of breast cancer have a higher-than-average risk of the disease, they should strive to minimize risk factors that are under their control, Dr. Amtul R. Carmichael, one of the researchers on the study, told Reuters Health.

Studies have found that overweight women generally have a higher risk of developing breast cancer than their thinner counterparts - possibly because excess fat raises the body’s levels of estrogen and other hormones that can help fuel the growth and spread of breast tumors.

Research also suggests that women who regularly exercise can help cut their risk of the disease. It’s possible that exercise is beneficial because it helps women control their weight, but that is not fully clear.

“The exact relationship between physical activity, obesity and breast cancer is quite complex and not fully understood,” explained Carmichael, a consultant breast surgeon at Russells Hall Hospital in Dudley, England. It’s not known, for example, whether exercise helps lower breast cancer risk even in the absence of weight loss.

The bottom line for women, according to the researcher, is that they should try to exercise and maintain a healthy weight as they age - and this is especially important for women with a family history of breast cancer.

It’s concerning that so many women in this study were overweight even though most acknowledged it as a breast cancer risk factor, Carmichael noted. Many women may need more education on what a healthy weight is, and how to achieve it.

SOURCE: International Seminars in Surgical Oncology, online January 8, 2009.