Prevalence and Clinical Correlates of Restless Legs Syndrome in an Elderly French Population: the Synapse Study

Background: The occurrence of restless legs syndrome (RLS) in elderly individuals is well known but the incidence and the clinical correlates in these subjects are still unclear. The present study explores the prevalence of and assesses symptoms associated with RLS in an older French population.

Methods: The study sample for this study comprised 318 subjects (219 women and 99 men), aged 68.6 +/- 0.8 years. All subjects underwent clinical assessment, nocturnal polygraphy, and cognitive and mood disorders evaluation. RLS was assessed with the standard validated criteria and severity was evaluated by the use of International Restless Legs Syndrome Study Group (IRLS) questionnaire.

Results: RLS was present in 24.2% of the sample, prevalence being greater in women (29.7%) than in men (12.1%). The mean IRLS score was 16.6 +/- 4.8, 67% of cases having mild to moderate range. Participants with RLS reported greater hypnotic (p < .001) and antidepressant medication intake (p < .001) and had higher anxiety (p < .001) and depression (p < .001) scores. Participants with RLS had lower cognitive performances at Stroop and Verbal fluency tests than participants without RLS (p < .05 and p = .002, respectively). These associations remained significant after multivariate adjustment for medication, depression, and subjective sleep.

Conclusions: Presence of undiagnosed RLS is higher in healthy elderly participants without previously diagnosed sleep disorders, affecting women more often than men. The presence of RLS increased the risk of anxiety and mood disorders and predispose to preclinical cognitive decline independently of anxiety, mood disorders, duration and quality of sleep, and medication.