Research has shown that obesity may increase the risk of estrogen-dependent breast cancer in postmenopausal women. Now, a recent study in the journal Cancer Epidemiology, Biomarkers & Prevention suggests that obesity may also increase the risk of triple-negative breast cancer, an aggressive form of the disease that is not fueled by estrogen and usually has a poor prognosis.
The researchers analyzed data from 155,723 postmenopausal women who participated in a large-scale study called the Women’s Health Initiative. The women were categorized into four groups, depending on their body mass index (BMI) scores. After an average follow-up period of 7.9 years, 2,610 women were diagnosed with estrogen receptor-positive breast cancer, and 307 were diagnosed with triple-negative breast cancer. The authors found that women with the highest BMIs were 35 percent more likely to develop triple-negative breast cancer and 39 percent more likely to develop other types of breast cancer than those with the lowest BMIs. Additionally, women who exercised the most had a lower risk of developing both estrogen receptor-positive breast cancer and triple-negative breast cancer compared to those who did not exercise.
Exercise is also vital for women whose breast cancer is in remission. In a 2005 American Medical Association study, researchers found that women who did at least four hours of moderate exercise per week—such as walking at an average pace—substantially reduced their risk of cancer recurrence.
If you’re a survivor and are interested in finding a community of other survivors to work out with, look into your local chapter of Team Survivor, an organization created just for this purpose.