Study links moderate activity to lower breast cancer risk

October 4, 2013, American Cancer Society

A large new American Cancer Society study adds to increasing evidence that physical activity reduces the risk of breast cancer in postmenopausal women. Researchers say moderate recreational activity was associated with a 14 percent lower risk and high physical activity with a 25 percent lower risk of breast cancer compared to women who were active at the lowest level. The study appears early online in Cancer Epidemiology, Biomarkers, and Prevention.

A large body of evidence shows that women taking part in regular have an approximately 25 percent lower risk of breast cancer compared to the most inactive. But still unclear are issues such as whether moderate intensity activity, like walking, imparts a benefit in the absence of vigorous exercise. Also unclear is whether the association differs based on tumor features, such as hormone receptor status, or by individual factors such as a woman's body mass index (BMI), weight status, and use of postmenopausal hormones. In addition, while prolonged periods of sitting have been associated with the risk of some cancers, the relation between sitting time and postmenopausal breast cancer risk is not well understood.

To learn more, American Cancer Society researchers led by Alpa Patel, Ph.D. compared exercise and breast cancer status in 73,615 taking part in in the CPS-II Nutrition Cohort, a prospective study of cancer incidence established by the American Cancer Society in 1992. During the 17-year study, 4,760 women in the study were diagnosed with breast cancer.

About one in ten (9.2 percent) women reported no recreational physical activity at the beginning of the study. Among those who were active, the average expenditure was equivalent to 3.5 hours per week of moderately-paced walking. Physically active women engaged primarily in moderate intensity activities, like walking, cycling, aerobics, and dancing rather than vigorous-intensity activities like running, swimming, and tennis. Among all women, 47 percent reported walking as their only recreational activity. Physically active women tended to be leaner, more likely to maintain or lose weight during adulthood, more likely to drink alcohol, and less likely to currently smoke. They were also more likely to use postmenopausal hormone therapy and to have had a mammogram in the past year.

Among those who reported walking as their only activity, those who walked at least seven hours per week had a 14 percent lower risk of breast cancer compared to those who walked three or fewer hours per week. Consistent with most prior studies, the most active women had 25 percent lower risk of breast cancer than the least active. The associations did not differ by hormone receptor status, BMI, weight gain, or postmenopausal hormone use. Also, sitting time was not associated with risk.

"Our results clearly support an association between physical activity and postmenopausal breast cancer, with more vigorous activity having a stronger effect," said Dr. Patel. "Our findings are particularly relevant, as people struggle with conflicting information about how much activity they need to stay healthy. Without any other recreational physical activities, walking on average of at least one hour per day was associated with a modestly lower risk of . More strenuous and longer activities lowered the risk even more."

Current guidelines recommend adults get at least two-and-a-half hours per week of activity, or 75 minutes per week of vigorous-intensity aerobic activity for overall health. But studies indicate less than half of U.S. adult women are active at these minimum levels. "Given that more than 60 percent of women report some daily walking, promoting walking as a healthy leisure-time activity could be an effective strategy for increasing physical activity among postmenopausal ," added Dr. Patel.

Explore further: Exercise, even mild physical activity, may reduce breast cancer risk

More information: Hildebrand JS, Gapstur SM, Campbell PT, Gaudet MM, Patel AV. Recreational physical activity and leisure-time sitting in relation to postmenopausal breast cancer risk. Cancer Epidemiol Biomarkers Prev; 22(10); 1906-12.

Related Stories

Exercise, even mild physical activity, may reduce breast cancer risk

June 25, 2012
A new analysis done by University of North Carolina at Chapel Hill researchers has found that physical activity – either mild or intense and before or after menopause – may reduce breast cancer risk, but substantial ...

Association between hormone replacement therapy use and breast cancer risk varies

September 3, 2013
Breast cancer risk associated with use of hormone replacement therapy (HRT) among postmenopausal women was variable when analyzed by race/ethnicity, body mass index (BMI), and breast density, according to a new study published ...

New approach evaluates effect of physical activity on estrogen metabolism in postmenopausal women

April 10, 2013
Researchers have generated new insights into the ways in which physical activity affects how much estrogen is broken down and secreted in the urine of postmenopausal women. These findings enhance understanding of the potential ...

Time spent watching television is not associated with death among breast cancer survivors

January 31, 2013
Spending a lot of time watching television after breast cancer diagnosis is not linked to death in these breast cancer survivors. It appears that after accounting for self-reported physical activity levels after diagnosis, ...

Recommended for you

How cancer metastasis happens: Researchers reveal a key mechanism

January 18, 2018
Cancer metastasis, the migration of cells from a primary tumor to form distant tumors in the body, can be triggered by a chronic leakage of DNA within tumor cells, according to a team led by Weill Cornell Medicine and Memorial ...

Modular gene enhancer promotes leukemia and regulates effectiveness of chemotherapy

January 18, 2018
Every day, billions of new blood cells are generated in the bone marrow. The gene Myc is known to play an important role in this process, and is also known to play a role in cancer. Scientists from the German Cancer Research ...

These foods may up your odds for colon cancer

January 18, 2018
(HealthDay)—Chowing down on red meat, white bread and sugar-laden drinks might increase your long-term risk of colon cancer, a new study suggests.

The pill lowers ovarian cancer risk, even for smokers

January 18, 2018
(HealthDay)—It's known that use of the birth control pill is tied to lower odds for ovarian cancer, but new research shows the benefit extends to smokers or women who are obese.

Researchers develop swallowable test to detect pre-cancerous Barrett's esophagus

January 17, 2018
Investigators at Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center have developed a simple, swallowable test for early detection of Barrett's esophagus that offers promise ...

Scientists zoom in to watch DNA code being read

January 17, 2018
Scientists have unveiled incredible images of how the DNA code is read and interpreted—revealing new detail about one of the fundamental processes of life.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.