WASHINGTON – Women who go through menopause early, before age 46, may have more than twice the risk of having a heart attack, stroke or other cardiovascular event later in life, researchers reported on Monday.
The risk was the same even when women took hormone replacement therapy, which doctors once prescribed expressly to prevent heart disease, the researchers said at a meeting of the Endocrine Society in San Diego.
"It is important for women to know that early menopause is a potential risk factor for cardiovascular disease, the number one killer of American women," Dr. Melissa Wellons of the the University of Alabama at Birmingham, who led the study, said in a statement.
"They can then work harder to improve their modifiable risk factors, such as high cholesterol and blood pressure, by exercising and following a healthy diet," Wellons said.
Doctors should routinely ask older women when they experienced menopause, she said. The average age of menopause is 51.
Her team studied more than 2,500 women who were 45 to 84 when the study started in 2000. Nearly 28 percent of them reported early menopause; 446 women or 18 percent had natural menopause and 10 percent had menopause caused by having their ovaries removed.
None of the women had a heart attack, stroke, chest pain known as angina, heart bypass surgery or a suddenly stopped heart before the age of 55.
But after that, the women who had early menopause were more likely to have had one of these things happen than the others. They were more than two times as likely to have one of these heart events, even when the researchers accounted for any extra weight gain.
Nearly 6 percent of women who went through menopause early had some sort of heart event, compared to 2.6 percent of women who had not gone through menopause or who went through it after age 47, they told the meeting.
"Our study is observational; therefore, we cannot conclude that early menopause somehow causes future cardiovascular disease," Wellons said. "However, our findings do support the possible use of age at menopause as a marker of future heart and vascular disease risk."
Before 2002, doctors widely prescribed hormone replacement therapy, or HRT, to lower the risk of heart disease or osteoporosis, both of which go up sharply after menopause.
But use of HRT plummeted in 2002 after the publication of the Women's Health Initiative study, which found an increased risk of ovarian cancer, breast cancer, strokes and other problems from hormone therapy. Studies have also found HRT does not protect against heart disease.
Sales of U.S. market leader Wyeth's combined estrogen-progestin therapy Prempro have fallen by about 50 per cent since 2001 to around $1 billion a year. Wyeth is now owned by Pfizer.