THURSDAY, May 17 (HealthDay News) -- The prevalence of stroke varies widely across the United States, with some states reporting rates more than twice as high as other states, a new study found.
Stroke prevalence also differs by race and ethnicity, age group and educational level, the researchers said.
Compounding the problem, less than half of stroke victims arrive at a hospital within two hours of the start of symptoms, when therapy is most effective, a second report found.
Both reports are published in the May 18 issue of the Morbidity and Mortality Weekly Report, a publication of the U.S. Centers for Disease Control and Prevention. May is also National Stroke Awareness Month.
Stroke is the third-leading cause of death in the United States. This year, an estimated 700,000 people in the United States will have a stroke, and 160,000 will die from it. Of those who live, 15 percent to 30 percent become permanently disabled, and 20 percent require institutionalization during the first three months after the stroke.
"Stroke is a huge public health problem both in the U.S. and in many developing countries," said Dr. Ralph Sacco, a stroke expert and professor and chairman of neurology at the University of Miami Miller School of Medicine. "The numbers are going up, principally because our population is aging, and people are surviving after heart disease and therefore at risk for stroke. Some projections say it won't be too long before we see about a million strokes per year in the U.S."
Previous stroke data had found stark regional differences, with a higher prevalence in the southeastern states, the so-called "Stroke Belt." There has also been state-specific and even county-level mortality data, but this is the first time state-specific prevalence estimates have been available.
"The novel finding in this report is that we have prevalence estimates which are a good gauge of disability and are important to begin to understand health-care costs, because strokes can be expensive to treat," said Jonathan Neyer, the first study's lead author and an epidemiologist with the CDC's Division for Heart Disease and Stroke Prevention.
The authors looked at state-by-state statistics for adults aged 18 and older.
Stroke prevalence ranged from a low of 1.5 percent in Connecticut to a high of 4.3 percent in Mississippi.
Almost one quarter of states, as well as the District of Columbia, had a stroke prevalence rate of 3 percent or above. Those states were Alabama, Arkansas, Illinois, Kentucky, Louisiana, Michigan, Mississippi, Missouri, Nevada, Oklahoma, Tennessee, Texas and West Virginia.
The lowest levels of stroke prevalence -- less than 2.6 percent -- were in Arizona, Colorado, Connecticut, Maryland, Massachusetts, Minnesota, Montana, New Jersey, North Dakota, Puerto Rico, Rhode Island, Vermont, Wisconsin, and Wyoming.
The national prevalence was 2.6 percent, which mirrors previous findings, the study authors said.
"Our findings correspond with a lot that is already known in the literature, but the amount of variation and magnitude of variation between states and ethnic/racial groups is always noteworthy," Neyer said.