A new study of a population of 1.3 million people in Ohio and Kentucky finds that the rate at which strokes occur has dropped significantly for men in recent years, but not for women.

PROVIDENCE, R.I. [Brown University] — Good news about men regarding the rate at which strokes occur is raising questions about women.

In a study led by Dr. Tracy Madsen, an assistant professor of emergency medicine at Brown University’s Warren Alpert Medical School, men showed considerable improvement in their stroke risk between 1993 and 2010, but women did not show a statistically significant drop.

In the journal Neurology, Madsen and colleagues analyzed data on strokes occurring in a population of 1.3 million people age 20 or older living in a five-county area of southwest Ohio and northern Kentucky. For men, the rate dropped from 263 strokes per 100,000 to 192 per 100,000 over the study period. Among women, the rate decreased from 217 strokes per 100,000 to 198 per 100,000, which is not a statistically significant difference.

In an American Academy of Neurology news story about the study, Madsen said the data do not explain why men have shown such improvement while women have not.

“For decades, women had a lower overall stroke rate than men, but now men appear to be approaching similar rates; while that is a good thing, it leaves one to wonder why women’s rates are not going down as well,” Madsen said. “At the end of our study, stroke rates for men and women were nearly the same.

“The overall decrease in stroke is clearly driven by men having fewer strokes caused by lack of blood flow to the brain resulting from blocked arteries or clots,” Madsen added. “What is not clear is why stroke rates for women remained stable while the rates for men decreased.”

The study was supported by the National Institute of Neurological Disorders and Stroke.