Medline ® Abstracts for References 2-5

A survey conducted through personal interviews was done in Canada to estimate the prevalence of subjective symptoms related to restless legs syndrome (RLS) and to sleep bruxism. Of the 2,019 respondents, all over 18 years of age, 15% reported leg restlessness at bedtime; 10% reported unpleasant leg muscle sensations associated with awakening during sleep and with the irresistible need to move or walk. Both these complaints are related to RLS. The prevalence of RLS-related symptoms increased linearly with age. Tooth grinding, a symptom related to sleep bruxism, was reported by 8% of the subjects; in contrast to RLS-related symptoms, the prevalence of tooth grinding decreased linearly with age. RLS-related symptoms were reported more frequently in Eastern provinces than in Ontario and Western Canada, and more frequently in Roman Catholic and French-speaking responders. This was not the case for sleep bruxism; between 14.5% and 17.3% of the subjects who reported subjective RLS-related symptoms also reported tooth grinding. Conversely, 9.6-10.9% of the tooth grinders reported RLS-related symptoms. These data suggest that both sleep movement disorders can be concomitant and that socio-geographic and age characteristics influence the prevalence of reports.

BACKGROUND: There are relatively few studies on the prevalence of restless legs syndrome (RLS) in the general population, even fewer that used diagnostic questions covering all 4 essential diagnostic criteria defining the RLS symptom complex, and none that have reported on the 2 RLS phenotypes for patients seen by family physicians.

METHODS: To determine the prevalence of the symptom complex, diagnostic for RLS in a primary care patient population, a prospective population-based single-center study was performed. Every adult patient presenting for care in a small rural primary care practice with mostly white patients was surveyed for a 1-year period using a validated RLS diagnostic questionnaire.

RESULTS: A total of 2099 patients completed the questionnaire. Analysis revealed that 24.0% of these patients were positive for all 4 of the essential symptoms used to make the diagnosis of RLS and 15.3% reported these symptoms at least weekly. In addition, the RLS symptom complex was reported significantly more often by women than men and, as a whole, patients reporting the RLS symptoms were significantly older than patients withoutsymptoms. The prevalence of symptoms increased with age until about 60 years and then showed a steady decrease thereafter. Further, early-onset RLS was significantly more common in women than men.

CONCLUSIONS: A high prevalence of RLS symptoms was observed in this primary care population. This finding supports the need for heightened awareness in both the medical community and general population regarding this disorder, which can often be effectively treated within the primary care practice.

OBJECTIVE: To assess the prevalence and severity of restless legs syndrome (RLS) in the general community and to investigate its potential relationship with iron metabolism and other potential risk factors.

METHODS: This was a cross-sectional study of a sex- and age-stratified random sample of the general population (50 to 89 years; n = 701). The diagnosis of RLS was established by face-to-face interviews; severity was graded on the RLS severity scale. Each subject underwent a thorough clinical examination and extensive laboratory testing.

RESULTS: The prevalence of RLS was 10.6% (14.2% in women, 6.6% in men); 33.8% of all patients with RLS had mild, 44.6% had moderate, and 21.6% had severe disease expression. None had been previously diagnosed or was on dopaminergic therapy. Free serum iron, transferrin, and ferritin concentrations were similar in subjects with and without RLS. However, soluble transferrin receptor (sTR) concentrations were different in subjects with and without RLS (1.48 vs 1.34 mg/L; p<0.001). Female sex and high sTR independently predicted the risk of RLS.

CONCLUSION: This large survey confirms the high prevalence, female preponderance, and underrecognition of restless legs syndrome in the general community. Although two-thirds of patients had moderate to severe disease, none was on current dopaminergic therapy.

To assess prevalence, disease burden, and costs of primary Restless Legs Syndrome (RLS) in the US. In 2007, 61,792 (20%) of 313,000 subjects from a representative US panel completed an online "global opinions" survey identifying respondents reporting all four diagnostic features of RLS. 4,484 met all criteria. 1,400 were randomly selected to complete a questionnaire to exclude those with diagnoses indicating possible secondary RLS. Those that did not have diagnoses associated with secondary RLS were asked to complete the Cambridge-Hopkins RLS questionnaire to exclude RLS mimics. Prevalence was estimated for the following groups: (1) RLS symptomatic, (2) primary RLS, and (3) primary RLS sufferers (symptoms≥2/wk with moderate-to-severe distress). The primary RLS completed a larger online survey including the IRLS, EuroQol, Work Productivity and Activity Impairment questionnaire, and questions about healthcare resource use. The validated diagnostic tools and exclusion of medical conditions likely to cause RLS provide a very conservative estimate of US census-weighted prevalence of 2.4% for primary RLS and 1.5% for primary RLS sufferers. About 33% of respondents had a physician diagnosis of RLS. Primary RLS sufferers had a mean productivity loss of 1 day/wk. All RLS-related costs increased with RLS symptom severity, with increasingly significant decrements in health status, sleep disturbance,and work productivity. Even this very conservative approach finds RLS in this cohort to be common, under-diagnosed, and carried a significant personal and social burden.