Women who go through menopause before age 46 are twice as likely to have a heart attack or stroke as women who hit menopause later, according to a new study.
"These are women who should keep in mind that they are at increased risk," said Dr Melissa Wellons, the lead author of the study from the University of Alabama at Birmingham.
"My advice to them would be to get your traditional risk factors checked... and do the things that we know, based on evidence, can improve your risk of developing heart disease, like keep your cholesterol in check and keep your blood pressure in check," she said.
The findings from a diverse group of US women support results of earlier studies, which had focused on white women. Little was known about age at menopause and heart disease risk among women of other ethnicities.
Average age of menopause in US is 51
Wellons and her colleagues collected health information through surveys of 2 509 women, including 331 Chinese, 641 black and 550 Hispanic women.
Close to 700 of them, or 28%, had gone through menopause early - before age 46. (The average age when women in the US stop having periods is 51.)
That group included women who went through menopause naturally or had a hysterectomy - surgery to remove the uterus - which can cause early menopause.
None of the women had cardiovascular disease at the beginning of the study. Researchers tracked them for an average of five years to see who ended up having a heart attack or stroke.
They found 23 of the women who had gone through menopause early, and 27 who hadn't, suffered a heart attack or cardiac arrest or died from heart disease, according to findings published in the journal Menopause.
Link to cardiovascular not clear
That translates to 3.3% of women in the early menopause group and 1.5% of the other group.
Similarly, 18 women - or 2.6% - of the early menopause group had a stroke during the study, compared to 19 (1%) of women who hit menopause later.
It's not clear why early menopause might be linked to cardiovascular disease.
Wellons said oestrogen could be related. Women's bodies produce little oestrogen after they go through menopause.
But there's no evidence taking hormones to make up for that change can lower a woman's risk of cardiovascular disease. In fact, the Women's Health Initiative study on hormone replacement therapy was stopped early when women taking hormones after menopause had a higher risk of heart disease and certain cancers.
A genetic association
Another possible explanation for the results is a shared trait underlying both early menopause and heart disease risk.
"It could be a genetic association, (where) genes that are related to ovarian function may also be associated with cardiovascular disease, and those two things are related but not through a common causal pathway," Wellons said.
She said more research is needed before doctors can know how to intervene to try to reduce the higher heart disease risk among women with early menopause.
Heart disease is the leading cause of death among US women. Combined with strokes, it is responsible for almost one in three deaths, according to the Centres for Disease Control and Prevention.
(Kerry Grens, Reuters Health, June 2012)
Women and heart disease