Restless legs syndrome may double the risk of heart disease

According to new research from the U.S. people who suffer from restless legs syndrome (RLS) are twice as likely to have a stroke or heart disease.

Restless legs syndrome is identified by a strong and irresistible urge to move the legs that is often described as an itching, tugging or gnawing feeling; the symptoms are worse when resting, causing difficulty in falling or staying asleep.

The researchers at Harvard Medical School in Boston conducted a large study involving 3,433 people with an average age of 68 who were enrolled in the Sleep Heart Health Study.

Participants were diagnosed with RLS by the use of a detailed questionnaire which included queries on whether they had been diagnosed with a variety of systemic diseases including cardiovascular disease and cerebrovascular disease.

Almost seven percent of the women and three percent of men were found to have RLS and the researchers say compared to people without RLS, and the risk is greatest in those with the most frequent and severe symptoms.

The study which is the largest of its kind found that people with RLS were more than twice as likely to have cardiovascular disease or cerebrovascular disease and the researchers say the results remained the same after adjusting for age, sex, race, body mass index, diabetes, high blood pressure, high blood pressure medication, HDL/LDL cholesterol levels, and smoking.

Study author Dr. John W. Winkelman says the association of RLS with heart disease and stroke was strongest in those people who had RLS symptoms at least 16 times per month but there was also an increased risk among people who said their RLS symptoms were severe compared to those with less bothersome symptoms.

Dr. Winkelman says although the study does not show that RLS causes cardiovascular and cerebrovascular disease, a number of potential mechanics for such a process exist.

He says most people with RLS have as many as 200 to 300 periodic leg movements each 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.

The researchers also say sleep deprivation may also play a role in the association with heart disease.

Winkelman says there are limitations to the study, including that the diagnosis of RLS was self-reported by questionnaire rather than by clinical interview.

The research, which confirms smaller studies, was supported by the National Heart, Lung and Blood Institute and is published in the January 1, 2008, issue of Neurology, the medical journal of the American Academy of Neurology.