Unhealthy lifestyles may be increasing the number of younger people suffering strokes, researchers have said.
A study showed that from the early 1990s to 2005 the proportion of stroke victims under the age of 55 in one region of the United States rose from 13% to 19%.
The average age at which people experienced a first stroke also fell from 71 to 69 over the same number of years.
Scientists looked at stroke rates in people between the ages of 20 and 54 in greater Cincinnati and northern Kentucky. Data for first strokes were collected over three periods between July 1993 and June 1994, 1999 and 2005.
Lead researcher Dr Brett Kissela, from the University of Cincinnati College of Medicine in Ohio, said: "The reasons for this trend could be a rise in risk factors such as diabetes, obesity and high cholesterol.
"Other factors, such as improved diagnosis through the increased use of MRI (magnetic resonance) imaging may also be contributing. Regardless, the rising trend found in our study is of great concern for public health because strokes in younger people translate to greater lifetime disability."
The findings are published in the latest online issue of the journal Neurology.
Dr Clare Walton, research communications officer at the Stroke Association, said: "This research is alarming. With the number of younger people having strokes increasing, greater strain will be placed on health services to support them with their recovery.
"This is particularly worrying given the proposed cuts to the NHS and social care which could seriously impact on patients' life after stroke. A stroke happens in an instant but its effects can last a lifetime, leaving many with long-term severe disabilities.
"This problem needs to be addressed now. In many cases a stroke can be prevented and everyone can reduce their risk by making a few simple healthy lifestyle changes. For example, eating a balanced diet, exercising regularly and getting your blood pressure checked can all make a huge difference."