Breast Cancer and Obesity: Postmenopausal Obese Women At Increased Risk

New findings published in JAMA Oncology reveal that obese postmenopausal women are at an increased risk of breast cancer.

In fact, the risk for breast cancer among the most obese women in the study jumped up to 58 percent higher than women of a normal weight.

For the study, researchers classified the most obese women as having a body mass index ( BMI) of 35 or higher.

"Obesity is a risk factor for breast cancer that is modifiable, making a healthy weight very important for prevention," said lead researcher Marian Neuhouser, a professor of epidemiology at the Fred Hutchinson Cancer Research Center in Seattle, in a news release. 

However, while the study found a link between obesity and an increased risk of breast cancer, it did not prove a cause-and-effect link, according to researchers, which may be due to estrogen.

"Obesity is known to increase estrogens in the postmenopausal women because estrogen is made by fat tissue," Neuhouser said. "Fat tissue also secretes inflammatory factors and is associated with insulin resistance -- all of which may increase breast cancer risk."

Statistics show that breast cancer is the most common type of cancer in women, despite race or ethnicity and the most common cause of death among women, according to the Centers for Disease Control and Prevention (CDC). It is the second most common cause of death from cancer among white, black, Asian/Pacific Islander and American Indian/Alaska Native women.

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