A new study from the University of Southern California showed that starting hormone therapy shortly after menopause had significantly less risk for cardiovascular disease.

Researchers at the University of Southern California enrolled 643 healthy women, half less than six years past menopause and half at least 10 years past it. The women in both groups were randomly assigned to take estrogen or a placebo. Women who still had a uterus also received progesterone or a placebo to protect against uterine cancer.

Over the course of five years, the women who started hormones soon after menopause had significantly  less progression of atherosclerosis (build up of fats, cholesterol, and other substances in and on the artery walls) of their carotid arteries—a marker for heart disease—than those taking the placebo. Those who started hormone therapy later in life did not show the same benefit.