National Institutes of Health (NIH) researchers recently published results showing a connection between hormone therapy use and breast cancer risk in women under 55.

According to a release, the scientists “discovered that women treated with unopposed estrogen hormone therapy (E-HT) were less likely to develop the disease than those who did not use hormone therapy.” The opposite was found for women who used estrogen plus progestin hormone therapy (EP-HT). Their risk of breast cancer was higher than those who were not treated with hormone therapy. The longer women used EP-HT, the higher their risk was. Additionally, “the association between EP-HT and breast cancer was particularly elevated among women who had not undergone hysterectomy or oophorectomy.”

The scientists hope their findings will aid clinical decision making.