The severity of increased restless legs syndrome may be associated with subsequent increased risk of stroke, according to a recent study.

Researchers found the link between increased restless legs syndrome and the increased risk of stroke, after considering other known risk factors such as age, smoking, hypertension, and unhealthy diet. There were 161 incident stroke cases during the six-year follow-up.

Restless legs syndrome is a neurological disorder in which there are throbbing, pulling, creeping, or other unpleasant sensations in the leg. Previous studies have found that restless legs syndrome double the risk of stroke and heart diseases compared to people without the disorder, Medical News Today reported.

"We were surprised at the importance of taking into account [restless leg syndrome] severity -- it was only severe [restless leg syndrome], not milder [restless leg syndrome], that was associated with increased risk of stroke," Xiang Gao, principal investigator and senior author of the study, said in a statement.

For the study, researchers collected and analyzed data from nearly 73,000 female registered nurses between the ages of 41 and 58 years in 2005. The study participants were free of diabetes, stroke, and pregnancy at the baseline.

The findings are detailed in the journal Sleep.