Fewer people in the US are having strokes than they were 50 years ago, but new research has revealed that the severity of the stroke has not declined.
More than 9,000 people were examined in the Framingham Study, published in today's Journal of the American Medical Association (JAMA).
The study found that number of 55 to 94-year-olds suffering from strokes, which cause brain cells to die and occurs after a blood clot or bleeding in the brain, had steadily decreased over the years.
Half a century ago, men aged over 65 faced a 19.5 per cent risk of suffering a stroke, but that has been reduced to 14.5 per cent. The risk for women is now 16.1 per cent, compared to 18 per cent in 1950.
However, led by Boston University's Raphael Carandang, the authors warned strokes were still a major problem for older people.
"The severity of stroke has not decreased and 30-day mortality has decreased significantly only in men, perhaps due to an older age at onset of stroke and more severe strokes in women," the authors said.
"These sobering trends emphasise that while improved control of risk factors has lowered incidence of stroke, there is a need for greater primary prevention efforts to reduce the lifetime risk, severity, and 30-day mortality following stroke."
According to the American Stroke Association, about 700,000 Americans suffer from strokes every year and 157,000 die as a result.