Prevalence of restless legs syndrome in a rural community in Japan

To assess the prevalence and clinical significance of restless legs syndrome (RLS) in a Japanese population, we carried out a community-based survey in a rural area of Japan. We sent questionnaires requesting information on demographics, the Center for Epidemiological Studies Depression scale, the Short Form-8, the Pittsburgh Sleep Quality Index, the National Institutes of Health/International RLS Study Group (IRLSSG) consensus questionnaire, and the IRLSSG severity scale for RLS (IRLS) to 5,528 eligible adult residents in the town of Daisen in the Tottori prefecture of Japan. Next, we performed telephone interviews to identify subjects with probable RLS. Of the 2,812 subjects (51.1%) who gave complete answers on the IRLSSG questionnaire, 50 (1.8%) were judged as RLS positive. The prevalence of RLS was significantly higher in women than in men, and significantly lower in individuals 60 years of age or older. Multiple logistic regression analysis revealed that the existence of RLS was significantly associated with depression, lowered mental quality of life, and sleep disturbances. The prevalence of RLS in adult Japanese populations may be lower than that reported in Caucasian populations. However, in a group of Japanese subjects, RLS had a significant impact on daytime functioning as well as subjective sleep quality.