Study: Obesity Increases Breast Cancer Risk, Preventing Weight Gain Key

Postmenopausal women who are overweight — and especially obese — have a greater risk of developing breast cancers, finds a new study that highlights the importance of preventing weight gain, as it also raises questions about whether losing weight necessarily reduces that risk.

The study adds to a consistent body of research showing that overweight and obesity increases women’s risk of postmenopausal breast cancers. It was published yesterday in JAMA Oncology.

AICR estimates that a third of US breast cancers could be prevented if women were at a healthy weight throughout life, were active and did not drink alcohol.

In this study, as other research has seen, the heavier the women, the greater the risk. Women categorized as the most obese were at almost double the risk of the most common type of breast cancer, ER-positive, along with PR-positive tumors. These cancers are fueled by the hormones estrogen and progesterone, respectively.

The study used data from approximately 67,000 women who were all part of the Women’s Health Initiative trials. That study focused on preventing certain cancers, heart disease and osteoporosis. When the women entered the study in the mid 1990s they were 50 to 79 years old, and they were weighed. They also answered questions about their lifestyle habits, medical history and other health risk factors. After that, they were weighed annually and had regular mammograms. Continue reading


Study: Eating High Amounts of Fats May Increase Risk of Certain Breast Tumors

For both pre- and postmenopausal breast cancers, the many studies looking on whether dietary fat matters has resulted in no clear conclusions. Now comes a study from Italy suggesting that it does for certain types of breast tumors, including the most common type.Fat, Fat and Fat

The study suggests that consuming high amounts of total fat, and saturated fats specifically, links to increased risk of breast tumors fueled by the hormones estrogen and progesterone. About three quarters of US breast tumors are estrogen-receptor positive (ER+). The majority of those also grow in response to progesterone.

The increased risk was most pronounced for high amounts of saturated fat, the type of fat from burgers, butter and primarily animal sources.

Here’s the study abstract, published in the Journal of the National Cancer Institute.

This is one study, and it will be added to the body of evidence on breast cancer prevention in AICR/WCRF’s Continuous Update Project (CUP). In the latest CUP report, there was not enough evidence on total dietary fat to make a conclusion for pre- or postmenopausal cancers. Continue reading