Women have a one-in-five lifetime risk of of stroke, while the equivalent risk for men is one in six, Dr. Sudha Seshadri, assistant professor of neurology at Boston University School of Medicine, told United Press International. That is almost twice a woman's lifetime risk for breast cancer, which is estimated at one in nine. "What this means is that stroke -- just like heart disease -- is a women's disease," she said.
Using data from the ongoing Framingham Heart Study, Seshadri was able to present the first snapshot of lifetime stroke risk for Americans. She collected data from 5,000 middle-aged, stroke-free volunteers in the study. The volunteers were followed every two years for up to 40 years or until they were diagnosed with a first stroke, she said. Seshadri presented her findings at the 29th International Stroke Conference.
During follow-up, 859 of the volunteers suffered a first stroke and most of those strokes -- 86 percent -- were caused by blood clots that cut off the blood supply to the brain.
In addition to lifetime risk, Seshadri's team calculated short term risk by 10-year intervals: at ages 55, 65, 75 and 85. The risk was higher for women at age 55, about the same for men and women at ages 65 and 75, but at age 85, "the risk for stroke risk for women was 16 percent, while for men it was just 9 percent."
She women -- and men as well -- can reduce their stroke risk significantly by keeping their blood pressure under control. "That means a blood pressure of less than 120 systolic and less than 80 diastolic," she said. "So instead of a one in five chance a woman would have about a one in 10 chance."
The lesson, said Seshadri, is women need to pay as much -- and possibly more -- attention to stroke risk factors than men do.
"Controlling blood pressure and avoiding smoking are especially important," she said.
Beyond smoking and high blood pressure, stroke recently has been linked to a group of risk factors called the metabolic syndrome. Components of the metabolic syndrome include a waist measurement of more than 40 inches for men and more than 35 for women, blood pressure of 130/85 milligrams of mercury, or mmHg, or higher and high triglycerides or low HDL -- the so-called good cholesterol.
Evidence of the syndrome also includes not metabolizing sugar properly -- considered a pre-diabetic state -- elevated levels of blood-clotting factors, and elevated C-reactive protein, an inflammatory marker found in the blood and considered a sign of heart disease.
A person showing at least three of these risk factors meets the criteria for metabolic syndrome.
Stroke expert Dr. Edgar J. Kenton III, a clinical professor of neurology at Thomas Jefferson University in Wynnewood, Pa., told UPI that high blood pressure accounts for about 60 percent of strokes, but added he thinks metabolic syndrome could explain most of the other 40 percent as well.
Dr. Bernadette Boden-Albala of Columbia University in New York said an ongoing study of almost 3,300 residents of the city suggest metabolic syndrome is responsible for "35 percent of strokes seen in Hispanics. That means that if we could eliminate the metabolic syndrome in this population we could reduce the number of strokes by 35 percent."
Likewise, a second study from the Framingham researchers found metabolic syndrome was responsible for about 20 percent of the strokes in the mostly white study population.
Not everyone is convinced emphasizing risks associated with the metabolic syndrome is an effective preventive strategy, however.
Dr. George Howard, professor and chairman of the department of biostatistics at the University of Alabama in Birmingham, told UPI not all risk factors are equal.
"We know high blood pressure is the 800 pound gorilla of stroke," he said, explaining that high blood pressure is probably the most significant risk factor.
The metabolic syndrome, Howard continued, gives equal weight to all risk factors "but says that if you have more than three of these factors, that is a problem." He said he suspects that, taken together, these risk factors add up to trouble and he is worried people will walk away with a false sense of security if they have "only one or two risk factors."
Howard noted he is significantly overweight himself, "and that is a real risk for me," but "I have a good risk profile if you consider the other risk factors." He added he knows he cannot afford to overlook his weight problem simply because "my blood pressure is good."
Considering that 5.2 million people worldwide died of stroke in 2001, Howard said, "we need to treat all risk factors."
Peggy Peck covers medical research and health issues for UPI Science News. E-mail firstname.lastname@example.org