Persons with restless legs syndrome, called RLS, face twice the risk of a stroke or heart disease compared to people who do not have the neurological condition, says a report in the journal Neurology.
The risk is greatest in people with the most frequent and the most severe symptoms of restless legs syndrome.
"This shows that restless legs syndrome has salience beyond just symptoms," says Dr. David Rye, at Emory University School of Medicine in Atlanta.
Dr. Rye says the study shows that the connection should be recognized.
RLS is a neurological disorder characterized by restlessness and a need to move the legs. Symptoms start or become worse when you are resting. The symptoms occur mainly at night and can interfere with sleep.
Some 5 percent to 10 percent of the adult population suffers from the syndrome, according to the study.
The new study, the largest of its kind, looked at 3,433 men and women, with an average age of 68, who were enrolled in the Sleep Heart Health Study.
The study was originally designed to look at the cardiovascular consequences of sleep-disordered breathing.
A diagnosis of RLS was based on a questionnaire completed by all study participants. The participants also answered questions about cardiovascular disease and stroke. Almost 7 percent of women and 3.3 percent of men in the study had RLS.
Persons with the syndrome were more than twice as likely to have cardiovascular disease or stroke. The association was strongest among those who had RLS symptoms a minimum of 16 times a month and among those who said their symptoms were severe.
The study cannot prove a cause-and-effect relationship, but such a link could make physiological sense.
Most people with RLS have up to 300 periodic leg movements a night, and those movements are associated with increases in blood pressure and heart rate, say the study authors.
Also, persons with RLS often also suffer from sleep deprivation, which has been associated with cardiovascular disease.
"The direct data would suggest that the disrupted sleep and arousals that occur with RLS are really what's contributing to hypertension and heightened autonomic nervous system activity, which in turns leads to cardiovascular [problems]," says Dr. Rye.
"But this [study] can't answer that kind of question," he adds
The next study should look to see if treatments for RLS reduce the risk for heart disease and stroke, says Dr. Rye.
"Nobody has done that, because nobody has recognized that there was a problem," he says.
One expert adds a cautionary note to the study's findings.
"This study is very well done, and the conclusions of the study are very measured,” says Dr. Paul Greene, at New York-Presbyterian Hospital/Columbia University Medical Center.
“In other words, the authors acknowledge that they can't prove that what they're studying actually causes strokes or heart attacks.
"They also could have picked up people with other syndromes, neuropathies [nerve damage], and things that could influence strokes and heart attacks,” he says.
“There are a lot of ways in which this study could be misleading," he explains. "They will have to do something to follow up on this before pushing a panic button.”
Neither physician was involved with the study, which was conducted by researchers from Harvard and other institutions.
Earlier studies showed an association between restless legs syndrome and cardiovascular disease, but the studies had limitations.
RLS has also suffered from a public image problem, which may explain why so few studies have explored the condition.
"RLS has borne the brunt of a lot of skepticism," explains Dr. Rye. "Snoring started out the same way... It took decades to convince primary-care physicians that we have to treat sleep apnea, that it's not just a nuisance that dad snores.
"It [sleep apnea] has a huge added risk for obesity and stroke and hypertension and cardiovascular disease," he says.
Always consult your physician for more information.
Restless legs syndrome (RLS) is a neurological disorder [often associated with sleep] in which a person experiences unpleasant sensations in the legs, which are described as:
These sensations usually occur in the calf area, but may be felt anywhere from the thigh to the ankle. One or both legs may be affected.
For some persons, the sensations are also felt in the arms. Persons with RLS have an irresistible urge to move the affected limb when the sensations occur.
Some individuals, however, have no definite sensation, except for the need to move.
Sleep problems are common with RLS because of the difficulty it causes in getting to sleep.
The cause of RLS is still unknown. RLS affects about 12 million individuals in the US.
Sensations occur when the person with RLS lies down or sits for prolonged periods of time, causing the need to move the legs for temporary relief of symptoms by stretching or bending, rubbing the legs, tossing or turning in bed, or getting up and pacing.
In addition, it can include a definite worsening of the discomfort when lying down, especially when trying to fall asleep at night, or during other forms of inactivity, including just sitting; or a tendency to experience the most discomfort late in the day and at night.
Your physician can diagnose RLS based on your signs and symptoms, a complete medical history, and a physical examination.
In addition, tests may be performed such as laboratory tests or a sleep study.
Treatment options for restless legs syndrome may include:
Always consult your physician for more information.
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