Older women with excess body fat, even if they have what's considered a normal body-mass index, could be at greater risk for breast cancer, according to a study published Thursday in the medical journal JAMA Oncology.
"We do find that excess body fat in those who are post-menopausal with a normal body mass index is associated with about a doubling in the risk of estrogen-dependent breast cancer," said Dr. Andrew Dannenberg , one of the study's authors and director of cancer prevention at the Sandra and Edward Meyer Cancer Center at Weill Cornell Medicine.
The American Cancer Society says estrogen-dependent cancers , called ER-positive breast cancer in the study, occur when the receptor proteins in or on cells attach to the hormone estrogen and rely on it to grow.
The researchers studied 3,460 American women between the ages of 50 and 79 who had gone through menopause. The women were part of the Women's Health Initiative and had their body composition measured at the beginning of that program, Dannenberg said. Of those women, 146 developed ER-positive breast cancer, and the researchers looked for a relationship between excess body fat and the development of this cancer.