CHICAGO -- High blood pressure, a key risk factor for stroke, is 60 percent more prevalent in Europe than north America, a study released Tuesday said.

A comparison of eight national surveys conducted in the 1990s showed that the condition was much more common in European nations than in the United States or Canada, with the highest rates seen in Germany and the lowest in the United States.

The six European nations surveyed had a combined prevalence of 44 percent versus North America's 28 percent, according to the study in the Journal of the American Medical Association.

The hypertension rates (defined as a blood pressure reading of 140 over 90) were closely correlated with fatal strokes, and less so with cardiovascular disease.

Researchers at Loyola University Stritch School of Medicine in Maywood, Illinois, who crunched the numbers did not examine the reasons for the striking differences, but speculated that more aggressive treatment of the condition this side of the Atlantic and dietary differences might explain the disparity.

"The European diet is higher in sodium and lower in fruits and vegetables, particularly Northern Europe," AFP quoted Richard Cooper, co-author of the study and chairman of Loyola University's Department of Preventative Medicine, as saying.

Stateside, the medical community's aggressive and early treatment of the condition is thought to have contributed to a 16 percent decline in hypertension in the United States in the last 20 years.

The United States and Canada have the lowest stroke rates in the world, in part because of low blood pressure in the general population, according to background information in the study.

"The potential for both prevention and better pharmacologic control would thus appear to be substantial for Europe," the authors wrote.

"These observations underscore that BP control is central to the prevention of the cardiovascular complications of hypertension, especially stroke," concluded a group of experts from the University of Leuven, in Belgium in an accompanying editorial. The data was based on an analysis of studies from Germany, Finland, Sweden, Britain, Spain, Italy, Canada and the United States involving volunteers aged from 35 to 74.