Early menopause could mean an increased risk of stroke caused by blocked blood vessels, according to a new study. Yet for each year of menopause delay, stroke risk fell by 2%.
Stroke is the second-leading cause of death worldwide, and women have a 4% higher lifetime stroke risk than men. Some studies show women who experience menopause at an earlier age have a higher risk of heart disease in general. But research has produced mixed results on the relationship between stroke and the age menopause started.
The study, published Thursday in the American Heart Association journal Stroke, looked at data from 16,244 postmenopausal women, ages 26-70, in the Netherlands.
After following the women for about 15 years and adjusting for various factors, researchers found women whose menopause occurred before age 40 had 1.5 times higher risk of ischemic stroke than women who experienced it between ages 50-54. Researchers also discovered a 2% lower stroke risk for each year menopause was delayed.
The risk between earlier menopause and stroke was limited to ischemic stroke, which is caused by a vessel blockage, and not hemorrhagic stroke, which occurs when a weakened vessel ruptures. The study also found the link between age at menopause and stroke was stronger for women who experienced natural menopause than for those who experienced menopause after surgery to remove the ovaries.
"It is of utmost important for all women to try and achieve optimal cardiovascular health before and after menopause, but it is even more important for women with early menopause," said Dr. Yvonne van der Schouw, the study's co-author and a professor of chronic disease epidemiology at Utrecht University in the Netherlands.
The results point to the need for new research into the link between early menopause and stroke risk, van der Schouw said, adding that further studies "may eventually lead to new, still unknown pathways and new clues for preventive measures."
Scientists already have been studying how hormone replacement therapies in early menopause might improve cardiovascular health. According to an AHA scientific statement published last year in its journal Circulation, certain hormone replacement therapies have cardiovascular benefits, decrease the risk of Type 2 diabetes and protect against bone loss.
A growing body of research also is looking at how estrogen impacts a woman's brain health.
A 2019 study in the journal Menopause found giving women estrogen early—within the first five years of menopause—might protect against cognitive decline. It also showed women exposed longer to natural estrogen because of longer reproductive periods had better cognitive function later in life.
Dr. Samar El Khoudary, who was not involved in the new research, said the study was limited by the use of data that relied on participant questionnaires to report details on menopause.
Still, she said, "this study as well as other similar studies help make us better aware of the risks related to menopause when it comes to cardiovascular health."
She called for more studies to examine how hormone replacement therapy impacts age at menopause and stroke. "It's the big elephant in the room (since) midlife women use hormone therapy to treat menopause-related symptoms," said El Khoudary, an associate professor of epidemiology at the University of Pittsburgh's Clinical and Translational Science Institute.
But whether or not they use hormone replacement therapy, women experiencing menopause need to educate themselves about the risk of stroke and what they can do to prevent it, El Khoudary said.
"During midlife when women transition through menopause, women need to maintain physical activity, have a healthy diet and a healthy weight, stop smoking, and get enough sleep," she said. "At this stage, reducing their risk becomes very important."