People with restless legs syndrome are twice as likely to have a stroke or heart disease compared with people without the condition, and the risk is greatest among those with the most frequent and severe symptoms, according to the largest restless legs syndrome study to date.

The 2008 study involved 3,433 men and women enrolled in the Sleep Heart Health Study, a large prospective cohort study of adults age 40 and older designed to investigate obstructive sleep apnea and other sleep-disordered breathing as risk factors for the development of cardiovascular disease. Participants were diagnosed with restless legs syndrome by detailed questionnaire and were asked if they had been diagnosed with a variety of systemic diseases including cardiovascular disease and cerebrovascular disease. Of the participants, nearly seven percent of women and three percent of men had restless legs syndrome.

Restless legs syndrome is a neurological condition characterized by the irresistible urge to move the legs, particularly when at rest. Although the relationship is unclear, restless legs syndrome is often associated with fibromyalgia and some other forms of arthritis and related conditions. 

The study does not show that the condition causes cardiovascular and cerebrovascular disease, but a number of potential mechanics for such a process exist, says study author John W. Winkelman, MD, PhD, of Harvard Medical School. “In particular, 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.”

Dr. Winkelman says there are limitations to the restless legs syndrome study, including that the diagnosis was self-reported via questionnaire rather than by clinical interview. The study was published in the Jan. 1, 2008 issue of Neurology.