Hormone replacement therapy, while appropriate to manage menopause symptoms in some women, doesn’t prevent chronic disease, according to a new study published in the Journal of the American Medical Association (JAMA).

These findings follow up a study conducted 20 years ago by the Women’s Health Initiative (WHI), which sought to discover if hormone therapy could reduce an older woman’s risk of developing diseases like osteoporosis and cancer.

The theory was based on the idea that estrogen has a protective effect on a woman’s body. While a woman’s risk of contracting some conditions, such as heart disease, are lower than a man's, the effect seems to dissipate following menopause, when a woman's hormone levels fall.

Menopause and Heart Disease: Is There a Link?

Stop the Presses

The WHI studies followed 27,347 postmenopausal women between 50 and 79 years of age who were enrolled in WHI hormone therapy trials, at 40 U.S. cancer centers in 1993. Women with an intact uterus received estrogen and progestin, while women with a prior hysterectomy received estrogen alone.

During the testing phases, two of the WHI hormone therapy trials had to be stopped after investigators found that the health risks outweighed the benefits. A 2002 study showed similar findings, after early data indicated that hormone replacement therapy drastically increased a menopausal woman’s risk of heart attack, stroke, blood clots, and breast cancer.

While hormone replacement therapy is still used in clinical settings, the question of its risks versus benefits remains.

“Menopausal hormone therapy has a complex pattern of risks and benefits. Findings from the intervention and extended post-intervention follow-up of the two WHI hormone therapy trials do not support use of this therapy for chronic disease prevention, although it is appropriate for symptom management in some women,” researchers concluded in the study released Tuesday.

An Increased Risk of Major Diseases

The new JAMA study found that the risks of estrogen and progestin in combination outweighed the drugs' benefits. The combination therapy increased the risk of coronary heart disease, breast cancer, stroke, blood clots, gallbladder disease, urinary incontinence, and dementia in women over the age of 65.

Still, the combined drug therapy results were not all bad. The woman using estrogen and progestin had fewer hip fractures, a decreased risk of diabetes, and fewer vasomotor symptoms. When the therapy stopped, so did the benefits and increased risks, although a slight elevation in breast cancer risk remained.

The patients receiving only estrogen had more balanced outcomes. They saw increased risks of stroke and venous thrombosis, but a reduced risk of hip and total fractures, and a nonsignificant reduction in breast cancer risk.

Researchers did note that women aged between 50 and 59 who received estrogen alone fared better in terms of heart attacks and death from all causes.

Learn More About Hormone Replacement Therapy