Stroke Incidence Has Declined for 50 Years
But, 30-day mortality rate has decreased significantly only for men, study finds
TUESDAY, Dec. 26, 2006 (HealthDay News) -- The incidence of stroke has dropped over the last 50 years, but stroke still remains a major problem for older Americans, a new study shows.
The findings, from the Framingham Heart Study, are based on an unusual half-century follow-up of more than 9,000 residents of the Massachusetts town who were first recruited in 1948. Since then, the risk of stroke by age 90 has decreased from 19.5 percent to 14.5 percent in men 65 and older, and from 18.0 percent to 16.1 percent for women.
Still, one in every six men and one in every five women who remain in the study will suffer a stroke in their lifetime, said Dr. Philip A. Wolf, professor of neurology at Boston University, and a member of the research team. The risk exists "because everyone in Framingham is living longer," he said.
"You can't get the diseases of the elderly if you don't live to an old age," Wolf explained.
Still, the study shows that "there clearly has been a good deal of progress" in fighting the risk factors for stroke, such as high blood pressure, smoking, obesity and diabetes, he said.
What the study, published in the Dec. 27 issue of the Journal of the American Medical Association, offers is a snapshot in time "as to how we are doing about stroke," Wolf said. "The information from Framingham gives us that opportunity because of its very detailed surveillance. It gives us a handle on what's happening."
The research also helps fill in a blank in statistics about stroke, said Virginia Howard, assistant professor of epidemiology at the University of Alabama, Birmingham, and chairwoman of the American Stroke Association's stroke statistics committee.
"It is very exciting because a lot of what we know about stroke at this point is based on studies of risk factors," she said. "There are not a lot of studies about incidence."
Howard did see one limitation of the study -- the fact that the participants are predominately of European origin, educated and middle class. Other studies have shown an increased risk of stroke in minority groups such as blacks.
But "the message is, 'yes,' we are making good progress in the education and treatment of risk factors, but there is still a way to go," she said. "We have to continue our education effort and also continue to support studies like this one that give us evidence on the success of that effort."
Still, the study also contained some troubling news. The severity of strokes that do occur has not lessened, and the 30-day mortality rate has decreased significantly only for men, "perhaps due to an older age at onset of stroke and more severe strokes in women," the report said.
"These sobering trends emphasize that while improved control of risk factors has lowered incidence of stroke, there is a need for greater primary prevention efforts," the researchers wrote.
Stroke is a cardiovascular disease affecting arteries leading to and within the brain. A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts. The result is that part of the brain can't get the blood and oxygen it needs, and starts to die, according to the American Stroke Association.
An estimated 700,000 Americans suffer a new or recurrent stroke every year. Nearly 157,000 people die each year from stroke, making it the No. 3 cause of death after heart disease and cancer.
To learn more about the risk factors for stroke and what can be done about them, visit the American Heart Association.