MEMPHIS, Oct. 8 (UPI) -- A new study provides the strongest evidence yet that patients with restless leg syndrome are at a higher risk of stroke, heart and kidney disease.

The study, published this week in the Journal of Sleep Research, took a unique approach to selecting study participants called "propensity matching."


Roughly a decade ago, researchers selected 3,700 men and women -- from a database of three million U.S. military service veterans -- who had been recently diagnosed with restless leg syndrome. A control group of veterans without RLS was then selected based on 20 or more matching demographic and clinical factors.

Researchers typically perform statistical analysis at the end of a study to account for mitigating factors. By looking at two groups that were more similar than they were different, the researchers were able to diminish effects of mitigating factors on their final results.

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And the results were pretty conclusive.

When the two groups were tracked over the next eight years, study participants with RLS were four times more likely to have a stroke or heart attack. The mortality rate of RLS patients was also 88 percent higher.

Restless leg syndrome is what sounds like -- the urge to move can be so overwhelming patients lose whole nights of sleep.

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The study didn't attempt to explain the connection between RLS and heart and kidney disease, but researchers point to previous studies that have linked sleeplessness to a variety of health problems, including heart disease and diabetes.

The research, which was funded by the Veterans Administration and the National Institutes of Health, was conducted by a team of scientists from the Memphis VA Medical Center, the University of Tennessee Health Science Center and the University of California, Irvine.

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