It has been concluded that the prevalence rate ranged from 3.9 to 15% of the general population (Ohayon et al., 2012) from recent epidemiologic analyses of different countries. The estimated prevalence of the RLS is around 7–10% in Caucasians (Ohayon et al., 2012) while there is a much lower incidence ranging from 0.1 to 12% among Asian population (Cho et al., 2009; Tsuboi et al., 2009; Chen et al., 2010; Panda et al., 2012; Shi et al., 2015). Compared with other countries, RLS is much more common in western countries. As numerous studies in western countries indicated the prevalence of 10, 10–15, and 5.5% in United States, Canada, and Europe (United Kingdom, Spain, Germany, Italy), respectively (Phillips et al., 2000; Ohayon and Roth, 2002). On the other hand, studies from Asian countries showed a pretty low prevalence rate of RLS. The first Indian population study on RLS revealed a prevalence of 2.9% (Panda et al., 2012) while a prevalence of 0.96% among inhabitants of Ajimu in Japan who were older than 65 years old (Tsuboi et al., 2009). Another RLS study in Shanghai, China revealed a prevalence rate of 1.4% among 2941 eligible individuals older than 18 years old (Shi et al., 2015). The significant difference between different ethnic populations may be due to different genetic background, ethnicity, geography, and environmental influences including natural environment and diet habits. The different populations targeted, research methodologies and diagnosis criteria used may contribute to this result as well.