To estimate prevalence and severity (using the International Restless Legs Syndrome Study Group Rating Scale (IRLS)) and to identify risk factors of restless legs syndrome (RLS).
Population-based cross-sectional study; 2005 randomly selected adults 18 years and above participated in a telephone interview in Norway and Denmark, employing the next-birthday technique.
Of the cross-section, 11.5% fulfilled the diagnostic criteria for RLS. Half of these reported the symptoms as moderate to very severe. Mean duration of the complaint was 10 years. Prevalence was higher in females than in males (13.4 vs 9.4%) and lowest in the youngest age group (18-29 years, 6.3%). From 30 years and above, no clear age-related difference was seen. Main predictors of RLS were insomnia (odds ratios: 1.71-3.16) and symptoms of periodic limb movements in sleep (3.20-7.85). The response rate was 47%, making the results less reliable.
This study indicates that there is a high occurrence of RLS among adults. Main predictors are insomnia and periodic limb movements in sleep.