CHICAGO (Reuters) - People with restless legs syndrome or RLS are twice as likely to have a stroke or heart disease and those with the most severe symptoms are at greatest risk, U.S. researchers said on Monday.
"The association of RLS with heart disease and stroke was strongest in those people who had RLS symptoms at least 16 times per month," Dr. John Winkelman, a sleep researcher at Harvard Medical School and Brigham & Women's Hospital in Boston, said in a statement.
"There was also an increased risk among people who said their RLS symptoms were severe compared to those with less bothersome symptoms," said Winkelman, whose study appeared in Neurology, the medical journal of the American Academy of Neurology.
Restless legs syndrome is marked by a strong, irresistible urge to move the legs that is often associated with an itching, tugging or gnawing feeling. These symptoms tend to worsen when resting, causing difficulty in falling or staying asleep.
About 5 percent to 10 percent of adults have the condition, and some 80 percent of sufferers move their legs periodically during sleep.
Winkelman and colleagues studied 3,433 men and women enrolled in a sleep study with an average age of 68. Of the participants, nearly 7 percent of women and 3 percent of men had restless legs syndrome, based on a detailed questionnaire.
The researchers found that people with restless legs syndrome were more than twice as likely to have heart disease or stroke. This finding remained even after adjusting for several factors, including obesity, diabetes, high blood pressure, high cholesterol levels and smoking.
The study does not show that restless legs syndrome causes heart disease or stroke. But Winkelman said the periodic leg movements associated with the condition could be a contributing factor.
"Most people with RLS have as many as 200 to 300 periodic leg movements per night of sleep and these leg movements are associated with substantial acute increases in both blood pressure and heart rate, which may, over the long term, produce cardiovascular or cerebrovascular disease," Winkelman said.
Sleep deprivation may also play a role in the association with heart disease, the researchers said.
The research, which confirms smaller studies, was supported by the National Heart, Lung and Blood Institute.
Reporting by Julie Steenhuysen; Editing by Cynthia Osterman