Original Open Access Restless legs syndrome and cancer: an analysis in three independent studies Andrea Fuhs 1* , Dunya Bentama 1 , Wolfgang Hofmann 2 , Henry Völzke 2 , Johannes Mathis 3 , Klaus Kraywinkel 4 and Klaus Berger 1 Abstract We report results from three independently conducted studies on the prevalence of cancer in restless legs syndrome (RLS) cases and non RLS cases. Already in 1955 Ekbom observed RLS in patients with subsequently detected cancer. Since then only three case reports and one article assessed the relationship between RLS and cancer patients undergoing chemotherapy. The observed proportion of RLS in these cancer patients (18.3%) was about twice as high as in general population studies. Two of our studies were general population based studies (Dortmund Health Study (DHS); Study of Health in Pomerania (SHIP)) and one was performed among members of the German and Swiss RLS patient organizations (Course of Restless Legs Syndrome-Study (COR-S)). Additionally we used data from the population based, regional cancer registry of the Muenster district for comparisons. Our data show that in all three studies the prevalence of cancer was higher in RLS cases than in non cases for both genders. In two of the studies the increased risk was in part explained by age. The data of the COR-Study revealed a statistically significant higher risk for cancer in RLS subjects compared to the population based data of the regional cancer registry of Muenster. Our results suggest a higher proportion of cancer among RLS cases compared to individuals without RLS. Given an RLS prevalence of about 5 to 10 percent in the general population, a need to rule out cancer in patients with a new onset of RLS, especially among the elderly patients is important. Keywords: Restless legs syndrome, cancer, prevalence, epidemiology © 2014 Fuhs et al; licensee Herbert Publications Ltd. his is an Open Access article distributed under the terms of Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0). his permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction Restless legs syndrome (RLS) is a common sleep disorder with a prevalence of 5% to 10% in the general population of Western countries [1–4]. Applying the four minimal criteria [5,6] published by the International RLS study group (IRLSSG) studies found an increasing prevalence with age [1,7] and women being approximately twice as often affected as men [2,8,9]. In 1955 Karl Axel Ekbom was the first to report a finding of RLS in patients with anemia [10], sometimes preceding the definitive diagnosis of cancer. Cancer prevalence also increases with age. For many types, cancer incidence and mortality is higher in men than in women [11]. However, due to a better survival of women [12], their overall prevalence of cancer is higher [13]. Due to the demographic change with a growing number of older people, both diseases will gain importance. Although there are a number of cross sectional studies reporting higher prevalences of non-cancer conditions, such as diabetes, an increased body mass index [2,7] and cardiovascular risk factors or diseases [1,14] in RLS cases compared to non cases, cancer prevalence in RLS patients, has not yet been studied in a similar comprehensive approach. Up to now only two further case reports [15,16] and a recent study that assessed the prevalence of restless legs syndrome in cancer patients undergoing chemotherapy are published [17]. The aim of our analysis was to evaluate the prevalence of cancer in individuals with and without RLS in three large independent studies in Germany. Materials and methods Data from three studies, independently conducted in Germany between 2002 and 2007, were used. Two of them were general population based epidemiologic studies the third one was performed among members of the German and Swiss RLS *Correspondence: fuhs@uni-muenster.de 1 Institute of Epidemiology and Social Medicine, University of Muenster, Germany. 2 Institute for Community Medicine, University of Greifswald, Germany. 3 Department of Neurology, Inselspital, Universitätsspital Bern, Bern, Switzerland. 4 Robert Koch-Institute, Berlin, Germany. Epidemiology Reports ISSN 2054-9911 | Volume 2 | Article 4 CrossMark ← Click for updates