Prevalence of restless legs syndrome in a Japanese elderly population

To estimate the prevalence of restless leg syndrome (RLS) in elderly Japanese people by means of a population-based survey of subjects aged > or = 65 years.

Studies conducted worldwide have revealed large variations in the prevalence of RLS among different populations. However, few studies have been done in Japan.

A population-based survey was carried out from 2003 to 2006 through a local healthcare project in the small town of Ajimu in a rural area of southern Japan. A Japanese translation of the questionnaire covering the four features of RLS as defined by the International RLS Study Group in 1995 was used to confirm the diagnosis of RLS. All participants aged > or = 65 years were invited to fill out the questionnaire. Subjects with positive results underwent face-to-face interviews.

A total of 1251 persons (men, 35%; mean age, 75.0+/-6.1 years) answered the questionnaire. Of these 1251 participants, 70 (5.6%) (men, 20%; mean age, 75+/-4.9 years) answered the questions on RLS positively. Face-to-face interviews and examination confirmed the diagnosis of RLS in 12 subjects. Therefore the overall prevalence of RLS in the elderly Japanese population was estimated at 0.96%, with a higher prevalence in women (1.23%) than in men (0.46%).

The overall prevalence of RLS among inhabitants of Ajimu aged > or = 65 years is 0.96%. Most of the subjects identified were women. The prevalence of RLS is lower in Japan than in studies conducted in European and North American populations.