Gender differences in the prevalence of restless legs syndrome/Willis-Ekbom disease

The restless legs syndrome (RLS) also known as Willis-Ekbom disease (WED) is one of the most frequent neurological sleep disorders. Epidemiological studies have shown consistently that it is more frequent in females than in males with male-to-female ratios mostly in the range of 1:1.5–1:2.0 in adult populations. One of the main candidates involved in this gender gap is pregnancy and specifically the transient form of RLS during pregnancy that affects around 20?% of females. Not only does the risk for RLS increase with increasing numbers of pregnancies, but RLS symptoms during that period are also a significant gender-specific risk factor for the development of chronic, idiopathic RLS later in life. Iron deficiency anemia is a further risk factor that is gender-specific inasmuch as it is more prevalent in females although the probability to develop RLS with iron deficiency anemia does not differ between men and women. While it is unknown whether and how these two gender-specific risk factors, i.e., pregnancy and iron deficiency anemia, interact and to what extent their effects are mediated by an individual genetic predisposition, they can at least explain part of the observed prevalence differences between males and females.