Strokes are most common in old age, but new research suggests that lifestyle is putting young people increasingly at risk for stroke too.
In a study of two US states, researchers found the rate of strokes among adults younger than 55 nearly doubled between 1993 and 2005. Among whites ages 20 to 54, the rate per 100 000 people rose from 26 to 48 and among African Americans, it climbed from 83 to 128 per 100 000.
The researchers could only speculate on possible explanations. One might be that doctors are detecting strokes in young people more often - both as a result of better imaging technology and of being more vigilant for stroke in the young.
"But I really don't think that's the major reason," said lead researcher Dr Brett M Kissela, of the University of Cincinnati College of Medicine. We're definitely seeing a higher incidence of risk factors for stroke now," he said.
Those risk factors include obesity, diabetes and high blood pressure. "And if you're developing them at the age of 20," Dr Kissela said, "then you may have a stroke at a younger age, too."
A definite increase
A researcher not involved in the study agreed that better diagnosis and a real increase in young people's risk of stroke are both probably at work.
"Now MRI allows us to detect smaller strokes," said Dr Mitchell S.V Elkind, of Columbia University in New York, who co-authored an editorial on the study.
"Strokes come in all shapes and sizes," Dr Elkind said. That includes subtle symptoms like mild degrees of blurry vision, weakness or numbness.
In the past, doctors might not have thought "stroke" when a relatively young person had symptoms like that. And MRI scans were not used often in the 1990s.
Dr Kissela's team found that in 1993-1994, only 18% of all stroke patients in their study had an MRI. By 2005, that figure had risen to 58%.
"But that probably doesn't explain it all," Dr Elkind said, referring to the rising incidence in young people. We know there's been an increase in obesity and diabetes," he said. He added that drug abuse can also cause strokes, and this study did find an increasing rate of drug abuse among young stroke patients over time.
What the study found
The results, published online in Neurology, are based on nearly 5 900 Ohio and Kentucky adults who suffered a first-time stroke between 1993 and 2005.
Over that time, 20 to 54 year olds accounted for a growing proportion of strokes: from 13% in 1993, to almost 19% by 2005.
The study group came from only two US states, but both Dr Kissela and Dr Elkind say the findings likely reflect what's happening nationally.
Indeed, a government study last year found a similar pattern nationwide: Between 1995 and 2008, the number of Americans ages 15 to 44 hospitalised for a stroke rose by more than a third.
"It's a small percentage of young people who have strokes," Dr Kissela said, "but it can happen."
(Reuters Health, October 2012)
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