By Margarita Nahapetyan
Women who experience early menopause are at a doubled risk of developing cardiovascular events such as ischemic stroke, according to a new research presented recently at the American Stroke Association's International Stroke Conference in San Diego.
"On the opposite end, women who enter natural menopause after the age of 54 are about 70 per cent less likely to have ischemic stroke compared with women who enter menopause before the age of 42," said Dr. Linda Lisabeth, PhD, an assistant professor of epidemiology and neurology at the University of Michigan School of Public Health in Ann Arbor, and a lead author of the study.
The most common type of stroke is an ischemic stroke which occurs when blood flow to an area of the brain is compromised by a blood clot. This leads to brain damage caused by the death of brain cells. About 144,000 people in U.S. die every year from a stroke, according to the American Stroke Association.
For the new study, Dr. Lisabeth and her colleagues involved 1,430 women who took part in the original, long-running Framingham Heart Study. None of the participants had had ischemic stroke before the age of 60, and all of them went through natural menopause.
The women then were followed for an average of 22 years, until they had their first stroke. During this time, 234 participants suffered the condition. According to the women, who reported their own ages at menopause, 56 experienced menopause before the age of 42, 1,299 went through it from the ages between 42 and 54, and 75 study participants experienced menopause at the age of 55 or older. None of the women had used estrogen before menopause.
The scientists found that there were 213 cases of ischemic stroke among the women in the middle group with the ages 42 and 54, 8 cases of the condition among the 75 late-menopause participants, and 13 strokes were developed by women who experienced early menopause. In particular, the women who experienced menopause before age 42 were twice as likely to have a stroke than other women.
Even after taking into consideration such factors as smoking, age, diabetes, heart disease, blood pressure, and other stroke risk factors, the study still showed that those women who went through early menopause had an increased risk of getting a stroke, than were the other women. "Four or five percent of all strokes in women could be attributed to this risk factor," Lisabeth said.Exactly how to explain the connection still remains unclear, she added, but experts believe that low estrogen levels associated with menopause might play a key role in increasing the risk of the condition.
Scientists suggest that women who go through menopause at an early age, should adopt a healthy lifestyle in order to reduce the risk of a stroke. They recommend more exercise, weight control, to avoid smoking, follow a balanced diet with lots of vegetables and fruits, and control blood pressure and lipid levels.
"Given the increased stroke burden in women, it is critical to understand risk factors unique to women so that new strategies for prevention can be considered," the researchers concluded. "Future studies, with measures of endogenous hormones, are needed to unravel the relationship between hormonal changes that occur with menopause, either premature or at the usual onset, and ischemic stroke."