In a study of the Greater Cincinnati/Northern Kentucky region, researchers found that the rate of strokes among adults younger than 55 years of age increased from 12.9% in 1993/1994 to 18.6% in 2005.

Stroke incidence rates in people aged 20 to 54 were significantly increased in both black and white patients in 2005 compared with earlier periods. The investigators also found that the mean age at stroke significantly decreased from 71.2 years in 1993/1994 to 69.2 years in 2005.

Possible explanations for the increase could be that physicians are detecting strokes in young people more often, both as a result of better imaging technology and more vigilant screenings, says a Reuters Health article.

"But I really don't think that's the major reason," lead researcher Brett Kissela told Reuters. "We're definitely seeing a higher incidence of risk factors for stroke now."

With people developing obesity, diabetes, and high blood pressure at a younger age, they also are increasing their risk of stroke at a younger age.

"This is of great public health significance because strokes in younger patients carry the potential for greater lifetime burden of disability and because some potential contributors identified for this trend are modifiable," the authors write.

The study is published in Neurology.