Is Restless Legs Syndrome Associated with Cardiovascular Disease?

Restless legs syndrome is a common condition characterized by a strong urge to move the limbs that is usually worse during the evening and nighttime hours, that is worsened by rest, and that improves with activity. However, the prevalence has varied in different studies, primarily depending on the criteria chosen to define this disorder. Prior studies using the International Restless Legs Syndrome Study Group criteria (1) have placed the prevalence between 3.9% and 14.3%.(2) Restless legs syndrome is associated with diverse adverse consequences.(3, 4) Health-related quality of life is reduced in those with restless legs syndrome and is lower in those with more severe disease. Restless legs syndrome also can lead to an increased prevalence of insomnia, depression, and anxiety.(3, 4, 5)

Several large epidemiologic studies have suggested a causal association between restless legs syndrome and cardiovascular disorders and hypertension after controlling for confounders such as age, witnessed apneas, and smoking.(6, 7, 8) Furthermore, a recent study using prospectively obtained data from the Nurses’ Health Study found an increased risk of incident nonfatal myocardial infarction in those with a history of restless legs syndrome for 3 years or more (hazard ratio, 1.80; 95% confidence interval [CI], 1.07-3.01).(9) The increased risk of coronary heart disease persisted after adjustment for blood pressure, diabetes duration, and use of diabetes medications. However, not all studies have observed an association between restless legs syndrome and cardiovascular disease.(10, 11)

In this issue of the Journal, additional evidence from 2 studies is presented relating to the putative association between restless legs syndrome and hypertension and cardiovascular disease.

In the first study by Winter et al,(12) 22,786 male participants of the US Physicians’ Health Studies I and II were studied. The mean age of the participants was 67.8 years. Restless legs syndrome was present in 7.5% of the participants, and the prevalence increased significantly with age. Furthermore, the odds of restless legs syndrome were higher in those with a history of diabetes. Conversely, frequent exercise and alcohol consumption of 1 or more drinks per day reduced the odds of restless legs syndrome. Of note, those with prevalent stroke had higher odds of a positive history of restless legs syndrome (odds ratio [OR], 1.41; CI, 1.05-1.86), whereas those with a history of myocardial infarction had lower odds of restless legs syndrome history (OR, 0.73; CI, 0.55-0.97).

The second study by Winter et al(13) analyzed data from 30,262 female health professionals (mean age, 63.6 years) participating in the Women’s Health Study. The prevalence of restless legs syndrome was 12.0% and more likely with severe obesity and smoking. Exercise≥4 times/week was associated with lower odds of restless legs syndrome (OR, 0.84; CI, 0.74-0.95). However, there was no association between restless legs syndrome and prevalent major cardiovascular disease defined as nonfatal myocardial infarction or stroke. Women who underwent coronary revascularization had increased odds (OR, 1.39; CI, 1.10-1.77) for restless legs syndrome compared with those with no intervention. However, this relationship also was no longer significant after excluding those with potential causes of restless legs syndrome.

To what extent do these new observations improve our understanding of restless legs syndrome?

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— Rohit Budhiraja, MD, Stuart F. Quan, MD

This article originally appeared in the March 2013 issue of The American Journal of Medicine.

Related articles:

Vascular Risk Factors, Cardiovascular Disease, and Restless Legs Syndrome in Women

Vascular Risk Factors, Cardiovascular Disease, and Restless Legs Syndrome in Men

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