Results have been reported from a study of more than 4,200 women who received a coronary calcium scan at Cedars-Sinai Medical Center between 1998 and 2012.

A coronary calcium scan is a CT scan that measures the amount of calcium in the heart’s arteries. Having higher levels of calcium is a marker for the build-up of plaque, which increases the risk of having a heart attack or stroke.

After accounting for age, coronary calcium score and cardiovascular risk factors including diabetes, high blood pressure and high cholesterol, women using hormone replacement therapy were overall 30 percent less likely to die than those not on hormone therapy. Women using hormone replacement therapy were also 20 percent more likely to have a coronary calcium score of zero (the lowest possible score, indicating a low likelihood of heart attack) and 36 percent less likely to have a coronary calcium score above 399 (indicative of severe atherosclerosis and high heart attack risk).

Estrogen is thought to be protective of heart health through its beneficial effects on cholesterol and on blood vessel function. Studies show that rates of heart disease increase after menopause, when estrogen levels fall. By replacing the natural estrogen lost during menopause, hormone replacement therapy could be one way for women to regain the cardiovascular benefits of estrogen.

Women and their doctors weigh many factors when deciding whether or not to use hormone replacement therapy.

This is an interesting study that supports existing evidence that hormone replacement therapy (HRT) slows atherosclerosis. While the study is at a disadvantage for the method of recording data retrospectively, the study size is large and the results are valuable.

Suggestions that women using hormone replacement therapy are overall 30% less likely to die than those not on HRT are greatly welcomed. However, more research is needed.