Email-based epidemiological surveys on restless legs syndrome in Japan

The prevalence, clinical significance and awareness of restless legs syndrome (RLS) have not been well identified in Japan. We conducted an Internet-based survey on the general Japanese population. Using an Internet-linked questionnaire, we evaluated 8126 respondents, consisting of a cross-section of Japanese adults aged 20 to 59 years. The questionnaire items consisted of demographic variables, the National Institute of Health/International RLS Study Group (IRLSSG) consensus questionnaire, the IRLSSG rating scale (IRLS), the Pittsburgh sleep quality index (PSQI), and questions regarding diagnosis and treatment. Probable RLS was found in 326 participants (4.01%). The prevalence was significantly higher in women (4.9%) than in men (3.0%), but did not differ by age. Most of the probable participants had mild to moderate IRLS severity and their average PSQI score was significantly higher than in unaffected participants. No probable RLS participants had been diagnosed with RLS, and only 7.7% had sought medical assistance. The prevalence of probable RLS in Japan is higher than in previous reports in Asia and, despite its low severity, the disorder is also thought to contribute to sleep disturbances in affected individuals. RLS is not well recognized in Japan and so promoting RLS awareness is necessary.