Feb. 20, 2009 (San Diego) -- Women who permanently stop menstruating before age 42 are twice as likely as other women to suffer a stroke, a large study shows.
“On the opposite end, women who enter natural menopause after age 54 are about 70% less likely to have a stroke compared with women who enter menopause before age 42,” says researcher Linda Lisabeth, PhD, assistant professor of epidemiology and neurology at the University of Michigan in Ann Arbor.
The data suggest that about one in 20 strokes in women can be attributed to early age at menopause, she tells WebMD.
The researchers only studied women who underwent natural menopause, not women who stop having their periods because of surgery or medication. Their findings were presented at the International Stroke Conference 2009 and simultaneously published online in the journal Stroke.
Estrogen Link Debated
For the study, the researchers followed 1,430 women who participated in the original Framingham Heart Study or the Framingham offspring study. None of them had had a stroke before age 60.
The women were followed for an average of 22 years, during which time 234 of them suffered an ischemic stroke. The most common type of stroke, an ischemic stroke occurs when blood flow to an area of the brain is compromised by a blood clot. This leads to the death of brain cells and brain damage.
Even after smoking,diabetes, blood pressure, and other stroke risk factors were taken into account, “age under 42 at natural menopause was associated with increased stroke risk,” Lisabeth says.
“The findings raise the hypothesis that decreasing estrogen levels after menopause may raise the risk of stroke, but current evidence regarding this hypothesis is inconsistent,” she says.
For example, the Women’s Health Initiative showed that giving women hormone pills after menopause actually increased their risk of heart disease, stroke, and certain cancers, says Larry B. Goldstein, MD, director of the Duke Stroke Center in Durham, N.C.
A drawback of studies like this is that they only show associations between two factors -- in this case, age at menopause, and stroke risk -- and do not prove cause and effect, he says.
“You can find something in epidemiological studies, but that doesn’t mean doing something will improve outcomes,” Goldstein tells WebMD.
In the face of the conflicting data, what should women who enter menopause at a very early age do? Frequent checkups with a doctor that specializes in early menopause may be prudent, the doctors say.
About 3% to 10% of women experience early, natural menopause before age 45, according to data cited in the study.