Epidemiology of restless legs syndrome in Korean adults

Demographic and clinical characteristics of patients with restless legs syndrome in spine clinic

Objective

The restless legs syndrome (RLS) is a common disorder affecting up to 5% to 15% of the general population, in which the incidence increases with age, and includes paresthesia in the legs. The purpose of this study is to investigate the incidence of RLS in spine center and to review clinical manifestations of this syndrome and its current treatments.

Methods

Over a period of a year, retrospective medical record review and lumbar magnetic resonance images were performed on 32 patients with RLS in spine clinic who were diagnosed by National Institutes of Health criteria. Affected limbs were classified as five. Two grading systems were used in the evaluation of neural compromises.

Results

The incidence of RLS was 5.00% (32/639). There were 16 males (50%) and 16 females (50%). The median age at diagnosis was 55.4 years (range, 25-93 years). There are no correlation between the affected limbs of RLS and neural compromises on the lumbar spine.

Conclusion

The RLS is a clearly common neurologic disorder of the limbs, usually the legs. The awareness of this syndrome can help reduce diagnostic error; thereby, avoiding the morbidity and expense associated with unnecessary studies or inappropriate treatments in RLS patients.

Pramipexole induced psychosis in a patient with restless legs syndrome

In the last few years, dopamine agonists (DA) have been used as first-line treatment for restless legs syndrome (RLS), a disabling sensorimotor disorder. Only recently have they reported some possible iatrogenic side effects, as shown below. The following case presents a RLS patient who developed hallucinatory and delusional symptoms with paranoid ideation after pramipexole assumption; these symptoms gradually decreased after pramipexole suspension and treatment by an oral antipsychotic therapy (quetiapine XR). Correlation between DAs assumption and psychotic symptoms is still not clear. The development of these side effects might be related to many risk factors such as genetic susceptibility, premorbid personality and psychosocial stressor; in order to minimise the risk of iatrogenic psychosis it could be useful to assess patients' vulnerability factors selecting an alternative medication regime.

Prevalence of restless legs syndrome in Ankara, Turkey: an analysis of diagnostic criteria and awareness

The aim of this study was threefold: (1) to investigate the prevalence of restless legs syndrome (RLS), in Ankara, Turkey; (2) to determine the predictive values of diagnostic criteria; and (3) to determine the frequency of physician referrals and the frequency of getting the correct diagnosis. A total of 815 individuals, from randomly selected addresses, above the age of 15, were reached using the questionnaire composed of the four diagnostic criteria. Individuals who responded by answering 'yes' for at least one question were interviewed by neurologists for the diagnosis of RLS. Frequency of physician referrals and frequency of getting the correct diagnosis of RLS were also determined for patients getting the final diagnoses of RLS. Prevalence of RLS in Ankara was 5.52 %; 41.0 % of the individuals diagnosed with RLS had replied 'yes' to either one, two or three questions asked by interviewers. However, only 21.3 % of individuals who replied 'yes' to all four questions received the diagnosis of RLS. Among the patients who had the final diagnosis of RLS, 25.7 % had referred to a physician for the symptoms and 22.2 % got the correct diagnosis. The RLS prevalence in Ankara was somewhere between Western and Far East countries compatible with the geographical location. Diagnostic criteria may not be fully predictive when applied by non-physician pollsters. Physician's probability of correctly diagnosing RLS is still low.

Diseases in patients coming to a sleep center with symptoms related to restless legs syndrome

Study Objective

To explore the profile of patients who visit a sleep center with symptoms that fulfill the four essential criteria for restless legs syndrome (RLS).

Design

A prospective study.

Setting

Outpatients from one sleep disorders clinic in Taiwan.

Participants

1,200 consecutive patients visit sleep disorders clinic with any sleep complaints.

Interventions

After completing a history and physical examination, all participants answered the RLS questionnaire. Subjects who fulfilled the four essential criteria for RLS were referred to a special clinic. A work-up including blood tests, polysomnography, and specialized neurological tests etc. was performed to make the final diagnosis.

Measurements and Results

A total of 1,185 participants were enrolled, and, of these, 131(11.1%) fulfilled the four essential criteria for RLS, and 121 completed the supplemental work-up. Their mean age was 47.6±13.3 and 52.9% were male. Insomnia and snoring were the most common chief complaints. Obstructive sleep apnea syndrome and other diseases were found in 103 patients. Only 18 (14.9%) patients had no comorbid condition and were diagnosed with primary RLS.

Conclusions

Symptoms of RLS are common in patients with sleep complaints. Even in a sleep clinic, using a questionnaire approach for identification of RLS has a low positive predictive value. Clinicians should pay attention to the limitations of the 4-item questionnaire in diagnosis of RLS and also the importance of a careful differential diagnosis to identify possible secondary causes of RLS.

Proteomic analysis of the cerebrospinal fluid of patients with restless legs syndrome/Willis-Ekbom disease

BACKGROUND

Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is a sensorimotor disorder that causes patients to experience overwhelming and distressing sensations in the legs compelling the patient to move their legs to provide relief. The purpose of this study was to determine if biomarkers in the cerebrospinal fluid can distinguish RLS/WED patients from neurological controls.

METHODS

We obtained CSF samples by lumbar puncture from 5 early-onset RLS/WED patients and 5 controls. We performed 2-dimensional difference in-gel electrophoresis (2D-DIGE). Proteins that were significantly altered were identified by Student's t-test. Protein spots that were differentially expressed (p ≤ 0.05, Av. Ratio ≥ 2.0) between RLS/WED and control CSF samples were identified using MALDI-TOF-MS. Statistical analyses of the validation immunoblot assays were performed using Student's t-test.

RESULTS

In this discovery study we identified 6 candidate CSF protein markers for early-onset RLS/WED. Four proteins (Cystatin C, Lipocalin-type Prostaglandin D2 Synthase, Vitamin D binding Protein, and β-Hemoglobin) were increased and 2 proteins (Apolipoprotein A1 and α-1-acid Glycoprotein) were decreased in RLS/WED patients.

CONCLUSIONS

Our results reveal a protein profile in the RLS/WED CSF that is consistent with clinical findings of disruptive sleep, cardiovascular dysfunction and painful symptoms. Moreover, protein profiles are consistent with neuropathological findings of activation of hypoxia inducible factor (HIF) pathways and alterations in dopaminergic systems. These data indicate the CSF of RLS/WED patients may provide information relevant to biological basis for RLS/WED, treatment strategies and potential new treatment targets.

The effect of ropinirole on the quality of life in patients with restless legs syndrome in Korea: an 8-week, multicenter, prospective study

Background and Purpose

Dopamine agonists are first-line drugs for treating the symptoms of restless legs syndrome (RLS). However, few studies have investigated the effect of dopamine agonists on the quality of life (QoL) in RLS patients. We conducted a study to determine whether ropinirole exerts positive effects on the QoL in RLS patients and to analyze the underlying factors.

Methods

Primary RLS patients from eight medical centers were recruited in the study. They were evaluated in the baseline phase using various questionnaires including the Korean versions of the International Restless Legs Scale (K-IRLS), RLS QoL questionnaire (K-RLSQoL), and the Short Form 36 Health Survey (SF-36). After taking ropinirole for 8 weeks the same questionnaires were again completed as a re-evaluation. We analyzed the statistical difference using a paired t-test, a Pearson's correlation, and a stepwise multiple regression in order to identify the factors associated with the QoL change.

Results

A total of 107 subjects, including 65 (60.7%) females, completed this study. They were aged 51.68±14.80 years (mean±SD) and had a symptom duration of 8.8±9.0 months. After treatment with ropinirole, there were significant improvements on the K-RLSQoL, SF-36, and K-IRLS. The Pearson's correlation analysis showed that the improvement of QoL in RLS patients was significantly correlated with the severity of RLS (r=0.236, p<0.014) at baseline.

Conclusions

The results from this study suggest that treatment with ropinirole can improve the QoL in RLS patients. The improvement in the QoL is more related with the improvement of RLS symptoms.

Restless legs syndrome in Korean patients with drug-naïve Parkinson's disease: a nation-wide study

BACKGROUND

Restless legs syndrome is a common neurologic disorder, and there is increasing evidence for a dopaminergic link between Parkinson's disease and restless legs syndrome. However, most previous studies did not take into account the effects of dopaminergic medication. We conducted a nation-wide, cross-sectional study to determine the prevalence and clinical characteristics of restless legs syndrome in Korean drug-naïve Parkinson's disease patients.

METHODS

One hundred and fifty-one drug-naïve patients with Parkinson's disease were enrolled from 18 centers in South Korea over the course of one year. Clinical profiles of parkinsonism, restless legs syndrome, psychiatric symptoms, and laboratory data were collected. The findings of subjects with and without restless legs syndrome were compared.

RESULTS

The prevalence of restless legs syndrome in drug-naïve patients with Parkinson's disease was 16.5%. Subjects with restless legs syndrome had a higher mean Hoehn and Yahr stage and more severe limb parkinsonism, especially tremor. There was, however, no difference in iron metabolism between patients with and without restless legs syndrome. Analysis demonstrated that Beck's depression inventory score was associated with the severity of restless legs syndrome.

CONCLUSION

Our study demonstrated an increased prevalence of restless leg syndrome in drug-naïve patients with Parkinson's disease than in the general population. Based on the association between parkinsonism and restless legs syndrome, and the unique characteristics of restless legs syndrome in patients with Parkinson's disease, we suggest that the pathophysiology of restless legs syndrome in Parkinson's disease differs from that in patients without Parkinson's disease.

Strategies for the treatment of restless legs syndrome

Restless legs syndrome (RLS) is a common neurological disorder of unknown etiology that is managed by therapy directed at relieving its symptoms. Treatment of patients with milder symptoms that occur intermittently may be treated with nonpharmacological therapy but when not successful, drug therapy should be chosen based on the timing of the symptoms and the needs of the patient. Patients with moderate to severe RLS typically require daily medication to control their symptoms. Although the dopamine agonists, ropinirole and pramipexole have been the drugs of choice for patients with moderate to severe RLS, drug emergent problems like augmentation may limit their use for long term therapy. Keeping the dopamine agonist dose as low as possible, using longer acting dopamine agonists such as the rotigotine patch and maintaining a high serum ferritin level may help prevent the development of augmentation. The α2δ anticonvulsants may now also be considered as drugs of choice for moderate to severe RLS patients. Opioids should be considered for RLS patients, especially for those who have failed other therapies since they are very effective for severe cases. When monitored appropriately, they can be very safe and durable for long term therapy. They should also be strongly considered for treating patients with augmentation as they are very effective for relieving the worsening symptoms that occur when decreasing or eliminating dopamine agonists.

Assessing health-related quality of life in patients with restless legs syndrome in Korea: comparison with other chronic medical diseases

BACKGROUND

There have been few quality of life (QoL) studies of patients with restless legs syndrome (RLS) in Asian countries. We studied the QoL of patients with RLS and compared it to normal controls and patients with hypertension, type 2 diabetes, or osteoarthritis in Korea.

METHODS

A total of 215 RLS patients (141 female; mean age 51.7 ± 13.5) were enrolled. All patients completed the questionnaires, including all the Korean versions of SF-36, RLS QoL, the International RLS Severity scale (IRLS), the Pittsburgh Sleep Quality Index (PSQI), and the Beck Depression Inventory-2 (BDI-2). These results were compared with the scores from normal controls (N=214) and from patients with hypertension (196), uncomplicated type 2 diabetes (185), or osteoarthritis of the knee (177).

RESULTS

The SF-36 QoL in patients with RLS was lower than that of the normal controls, and even lower than patients with hypertension or diabetes, but higher than those with osteoarthritis. The SF-36 Qol of RLS patients showed a significantly negative correlation with the severity of RLS symptoms(r=-0.430, p<0.001) and the severity of depression (r=-0.565, p<0.001), but was not significantly related to gender, age, or age-of-symptom onset (early or late-onset). Step-wise multiple regression identified three factors related to SF-36 QoL: depression (46.5% of RLS had responses on BDI-2 indicating depression) (β=-.899, p<0.001), RLS symptom severity (K-IRLS) (β=-.718, p<0.001), and gender (female) (β=-6.128, p=0.007).

CONCLUSIONS

These findings show that RLS has a considerable impact on the QoL of Koreans, which is comparable with studies of western countries. The QoL impairment relates to the degree of depression with RLS for Koreans.

Increased striatal dopamine transporter density in moderately severe old restless legs syndrome patients

BACKGROUND AND PURPOSE

Dopamine dysregulation in restless legs syndrome (RLS) may be varied by the severity of RLS, which could contribute to the conflicting results from previous functional neuroimaging studies on the central dopaminergic neurotransmission of RLS. The aim of this study was to observe whether reduced striatal dopaminergic neurotransmission is associated with moderate to moderately severe RLS.

METHODS

Thirteen elderly patients with RLS and 12 normal elderly controls were enrolled in the study. All the subjects were dopaminergic-drug naïve and twelve patients with RLS had the severity of moderate to moderately severe degree based on the International Restless Legs Syndrome Study Group (IRLSSG) Severity Scale. We compared dopamine transporter density (DAT) availability and D2 receptor density in the striatum between patients with RLS and controls using [(123)I]2β-carbomethoxy-3β-(4-iodophenyl)tropane single-photon emission computed tomography (SPECT) and [(123)I]iodobenzamide SPECT.

RESULTS

Dopamine transporter density of patients with RLS was increased in the caudate (P = 0.037), posterior putamen (P = 0.041), and entire striatum (P = 0.046) compared with that of normal controls. DAT density was higher in the anterior putamen of patients with RLS than controls, although statistically not significant (P = 0.079). There was no difference in the D2 receptor density between patients with RLS and normal controls in the whole striatum or any of subregions.

CONCLUSIONS

Dysregulation rather than simple upregulation or downregulation of central dopaminergic neurotransmission may underlie the pathogenesis of RLS, and decreased dopaminergic neurotransmission may cause moderate to moderately severe RLS in the elderly.

A community-based investigation on restless legs syndrome in a town in China

OBJECTIVE

To assess the prevalence and severity of restless legs syndrome (RLS) in a town in China and to explore potential factors correlated with the severity of the disease.

METHODS

Face-to-face home interviews were conducted among a random sample of 2101 residents in one town in China, all aged 16 years and above. An individual questionnaire was administered to all participants to obtain a diagnosis of RLS and other information. An additional questionnaire was then handed out to each patient diagnosed with RLS to collect information on RLS severity and potential factors correlating with RLS severity.

RESULTS

The prevalence of RLS in the studied population was 7.2%. The prevalence in women was significantly higher than in men and increased with age. Diabetes mellitus, anemia, arthritis, and varicose veins were also associated with RLS. Among the 152 patients, 21.7% were classified as having severe RLS. Multiple correlation analysis reveals that RLS severity was positively correlated with longer disease duration, number of cigarettes smoked per day, and level of work-related physical activity, but negatively correlated with level of leisure time physical activity.

CONCLUSIONS

RLS is common in the studied population. Lifestyle factors may be associated with RLS severity.

Efficacy and safety of pramipexole in chinese patients with restless legs syndrome: results from a multi-center, randomized, double-blind, placebo-controlled trial

BACKGROUND

We performed a six-week study of pramipexole vs. a placebo in Chinese restless legs syndrome patients.

METHODS

Overall, 305 enrolled patients were assigned randomly in a 2:1 ratio to the pramipexole group (N=202) and the placebo group (N=103).

RESULTS

Of 287 patients in the full analysis set, the pramipexole group showed significant improvement compared with the placebo group in the change of their International Restless Legs Syndrome Study Group Rating Scale of Severity (IRLS) total score from baseline to week 6 after adjustment of centers and baseline characters (-15.87±0.66 vs. -11.35±0.92, p<0.0001) and in the proportion of patients who were "much improved" and "very much improved" when measured by Clinical Global Impressions-Improvement (81.9% vs. 54.3%, p<0.0001). At week 6, the IRLS responder rate was 73.8% (pramipexole) and 48.9% (placebo) (p<0.0001) and the patient global impression responder rate was 68.6% (pramipexole) and 43.5% (placebo) (p<0.0001). The proportion of adverse events was 62.9% in the pramipexole group and 43.7% in the placebo group, respectively. No deaths occurred.

CONCLUSION

Pramipexole was effective and well-tolerated in Chinese patients with restless legs syndrome.

[Quality of sleep and serum lipid profile in patients with restless legs syndrome]

PURPOSE

The purpose of this study was to compare the quality of sleep with the serum lipid profile in patients who have restless legs syndrome (RLS).

METHODS

The data were obtained from 116 patients with RLS through questionnaires and blood sampling.

RESULTS

The results of this study showed correlations between lower quality of sleep and serum lipid profile (LDL Cholesterol) in patients with RLS (r=.19, p=.040). There were correlations for scores of quality of sleep from the, Pittsburgh Sleep Quality Index (PSQI) sub-region between lower subjective sleep quality and serum lipid profile (LDL Cholesterol) (r=.20, p=.026), between fewer hours of sleep duration and serum lipid profile (Total Cholesterol) (r=-.21, p=.024), and, between higher daytime dysfunction and serum lipid profile (LDL Cholesterol) (r=.42, p<.001) of patients with RLS.

CONCLUSION

Patients with RLS have sleep disorders with lower quality of sleep and changes in the serum lipid profile for total cholesterol and LDL cholesterol. That is, patients with RLS have lower quality of sleep and dyslipidemia compared to persons without RLS. Further research is needed to monitor serum the lipid profile in early stage symptoms of midlife adult patients with RLS and especially older women.

Restless legs syndrome: a comprehensive overview on its epidemiology, risk factors, and treatment

PURPOSES

Restless legs syndrome (RLS) is underdiagnosed and poorly understood by clinicians and the general public alike; accordingly, a broad literature review with information most relevant to general practice is needed to help dispel misconceptions and improve level of care.

METHODS

Specifically, this review comprehensively provides an epidemiological analysis of RLS and examines the risk factors and treatment options for RLS by compiling the findings of past RLS studies. These RLS studies were identified through a retrospective PubMed search. The epidemiological analysis was conducted by calculating a weighted mean average of all the relevant general population RLS prevalence studies, separated into geographical/racial categories.

RESULTS

A comprehensive analysis of RLS epidemiological studies finds the prevalence rate of RLS to be 5-15% in the general population with 2.5% of adults having symptoms severe enough to require medical intervention. Some of the risk factors for RLS include female gender, pregnancy, low iron levels, lower socioeconomic status, poor health, elderly age, comorbidity with Parkinson's disease, positive family history of RLS, and comorbidity with psychiatric disorders. A wide array of treatment options exist for RLS including pharmacological and nonpharmacologic interventions.

CONCLUSIONS

Clinicians' understanding of RLS enigma has recently improved due to the increased intensity of RLS research over the past decade. This review summarizes the current findings in the RLS field as well as providing guidelines for future RLS-related research.

Prevalence of restless legs syndrome in the rural town of Cassia dos Coqueiros in Brazil

OBJECTIVE

To estimate the prevalence and evaluate the characteristics and severity of restless legs syndrome (RLS) in an urban Brazilian community.

METHODS

A transversal study was conducted over an 18-month period. A neurologist conducted 1155 interviews using the diagnostic criteria of the International Restless Legs Syndrome Study Group (IRLSSG).

RESULTS

The lifetime prevalence of RLS was found to be 6.40%. Prevalence during the last year, the last month, and the last week were found to be 5.71%, 5.36%, and 4.15%, respectively. A greater proportion of women met diagnostic criteria for RLS compared to men (OR: 2.63, CI 95%: 1.54-4.51). Furthermore, participants with low monthly family income (<$1575 USD) had a lower prevalence of disease compared to those with a high monthly family income (>$1575 USD) (OR: 2.91, CI 95%: 1.41-5.98).

CONCLUSIONS

This is the first epidemiologic study of RLS conducted in a Brazilian population. The overall prevalence of disease and the greater proportion of RLS in women found in this study are similar to the findings of other studies conducted in western countries. The association of RLS with high family income is unpublished and should be confirmed in subsequent studies.

Epidemiology of restless legs syndrome: a synthesis of the literature

Restless legs syndrome (RLS) has gained considerable attention in the recent years: nearly 50 community-based studies have been published in the last decade around the world. The development of strict diagnostic criteria in 1995 and their revision in 2003 helped to stimulate research interest on this syndrome. In community-based surveys, RLS has been studied as: 1) a symptom only, 2) a set of symptoms meeting minimal diagnostic criteria of the international restless legs syndrome study group (IRLSSG), 3) meeting minimal criteria accompanied with a specific frequency and/or severity, and 4) a differential diagnosis. In the first case, prevalence estimates in the general adult population ranged from 9.4% to 15%. In the second case, prevalence ranged from 3.9% to 14.3%. When frequency/severity is added, prevalence ranged from 2.2% to 7.9% and when differential diagnosis is applied prevalence estimates are between 1.9% and 4.6%. In all instances, RLS prevalence is higher in women than in men. It also increases with age in European and North American countries but not in Asian countries. Symptoms of anxiety and depression have been consistently associated with RLS. Overall, individuals with RLS have a poorer health than non-RLS but evidence for specific disease associations is mixed. Future epidemiological studies should focus on systematically adding frequency and severity in the definition of the syndrome in order to minimize the inclusion of cases mimicking RLS.

Restless legs syndrome

Restless legs syndrome (RLS) is characterized by a compelling, often insatiable, need to move the legs, accompanied by unpleasant sensations located mainly in the ankles and calves. Because symptoms are brought on by inactivity, distress intrudes upon everyday, sedentary activities such as plane travel, car rides, and attending school, meetings, or the theatre. Symptoms show a diurnal preference for the evening and night, so disruption of sleep onset or maintenance is particularly common. RLS is associated with both lower ratings of quality of life and higher rates of cardiovascular disease. Four common genetic loci associating to RLS have recently been identified, but the molecular pathways by which they increase risk for RLS have yet to be determined. Both sensory (RLS) and motor (periodic limb movements of sleep) symptoms are responsive to dopaminergic medications, yet clear delineation of dopaminergic pathology has not emerged. Brain iron is reduced in many, but not all, patients with RLS. First-line treatment for RLS includes agents acting at D(2) and D(3) dopamine receptors.

Transcranial brain sonography in Parkinson's disease with restless legs syndrome

Substantia nigra (SN) hyperechogenicity assessed by transcranial brain sonography (TCS) is a characteristic finding in idiopathic Parkinson's disease (PD). In contrast, SN hypoechogenicity on TCS has been recently demonstrated in restless legs syndrome (RLS). RLS is one of the most common sleep problems in PD, but the pathophysiologic relationship between these two disorders has not been thoroughly elucidated. We compared the SN echogenicities of PD patients with and without RLS to investigate whether comorbid RLS in PD affects SN echogenicity and to explain the echogenic differences between idiopathic RLS (iRLS) and secondary PD-related RLS (pRLS). Sixty-three PD patients (median age 64.6 +/- 10.6 years), 40 iRLS patients (53.1 +/- 11.7 years), and 40 healthy controls (69.1 +/- 2.3 years) were enrolled in our study. All subjects answered a sleep questionnaire and underwent TCS. PD patients were subdivided into two groups, PD with RLS (PD+RLS, n = 26) and PD without RLS (PD-RLS, n = 37), and the sonographic findings of each group were compared. Although significant hyperechogenicity was detected in both the SN and SN/midbrain ratios in both PD subgroups compared with the controls and the iRLS group (P < 0.001), there were no significant differences in SN echogenicity between the PD+RLS and PD-RLS groups. Meanwhile, iRLS patients showed significant SN hypoechogenicity. In conclusion, comorbid RLS in PD did not have an impact on the sonographic SN findings. These results suggest that the pathogenesis of pRLS and iRLS involve different mechanisms. Further study will be required to clarify the association between RLS and PD.

Association study between antipsychotic-induced restless legs syndrome and polymorphisms of monoamine oxidase genes in schizophrenia

OBJECTIVE

This study aimed to investigate whether the monoamine oxidase (MAO) A and B genes are associated with antipsychotic-induced restless legs syndrome (RLS) in schizophrenia.

METHODS

We assessed antipsychotic-induced RLS symptoms in 190 Korean schizophrenic patients and divided the subjects into two groups: those with RLS symptoms (n = 96) and those without RLS symptoms (n = 94). Genotyping was performed for the variable number of tandem repeat (VNTR) polymorphism of the MAOA gene and A644G polymorphism of the MAOB gene.

RESULTS

There was no significant difference in the genotype and allele frequencies of all polymorphisms investigated between these two groups. However, the result of global haplotype analysis showed a significant difference in haplotype frequencies between male subjects with and without RLS symptoms (p = 0.013). The interaction between two polymorphisms had a significant effect on the RLS scores of both male (p = 0.047) and female (p = 0.028) patients.

CONCLUSIONS

These data do not suggest that the MAOA gene VNTR and MAOB gene A644G polymorphisms are associated with antipsychotic-induced RLS symptoms in schizophrenia. However, we found that the haplotype frequencies differed between the male schizophrenic patients with and without RLS symptom and the interaction between the two polymorphisms had a significant influence on the RLS scores of patients with schizophrenia.

The prevalence of restless legs syndrome in Taiwanese adults

AIM

Few studies have examined the prevalence of restless legs syndrome (RLS) in Asian populations, with existing data suggesting substantially lower rates of RLS in Asian populations compared with Caucasians. However, varying definitions of RLS as well as problematic methodology make conclusions about RLS prevalence in Asian populations difficult to interpret. The current study therefore examines the prevalence of RLS in Taiwanese adults.

METHODS

Subjects were 4011 Taiwanese residents over the age of 15 years. Data was collected using a computer-assisted telephone interviewing (CATI) system between 25 October 2006 and 6 November 2006.

RESULTS

The prevalence of RLS in Taiwanese adults was found to be 1.57%. In addition, individuals with RLS had a higher body mass index (BMI) and incidence of chronic conditions and comorbidities including insomnia, hypertension, cardiovascular disease, respiratory disease, arthritis, backache and mental illness. Women with RLS also had a higher incidence of post-menopausal syndrome.

CONCLUSION

Findings from the current study suggest that the prevalence of RLS in Taiwan is 1.57% by telephone interview. Individuals with RLS had a higher incidence of chronic insomnia and many other chronic disorders. The association and long-term consequences of RLS with these chronic disorders warrants further longitudinal observation and study.

Prevalence of idiopathic and secondary restless legs syndrome in Korean Women

OBJECTIVE

The aim of this study was to identify the prevalence of idiopathic and secondary restless legs syndrome (RLS) and to compare them among Korean women.

METHODS

A total of 1000 women aged 40-69 years from the general population were included in the study. The questionnaire used to gather data included modified International Restless Legs Syndrome Study Group (IRLSSG) criteria, and questions related to RLS.

RESULTS

Of the entire cohort, 65 subjects were diagnosed as having RLS according to IRLSSG criteria. The overall prevalence of RLS was thus 6.5%. Of those subjects with symptoms of RLS, 81.5% complained of insomnia. The age at the onset of RLS was 38.9 +/- 8.6 years. RLS symptoms were experienced every day by 18.5% of affected subjects. None of the RLS subjects revealed in this study had previously been diagnosed or treated for their RLS problems.

CONCLUSION

The prevalence of RLS reported herein is low compared with that reported for Western countries. Our study provides further evidence for low prevalence of RLS in Asian populations and supports the view that RLS is poorly recognized by both physicians and the general population, resulting in suboptimal management of the disorder.

Restless legs syndrome in a community sample of Korean adults: prevalence, impact on quality of life, and association with DSM-IV psychiatric disorders

STUDY OBJECTIVES

Conflicting reports on prevalence of RLS exist in Asian countries due to differences in sampling strategies and assessment instruments. We assessed the prevalence, correlates, quality of life, and psychiatric comorbidity of RLS in South Korea.

DESIGN/SETTING

Cross-sectional nationwide survey.

PARTICIPANTS

Nationally representative sample of 6,509 Korean adults aged 18-64.

MEASUREMENT & RESULTS

Face-to-face interviews based on the Korean translation of the four features of RLS defined by the International RLS Study Group (IRLSSG), the Korean version of Composite International Diagnostic Interview (K-CIDI), and EuroQol (EQ-5D) were conducted for all participants. The weighted prevalence of RLS in South Korea was 0.9% (men, 0.6%; women, 1.3%). Subjects with RLS had a lower quality of life according to EQ-5D than those without RLS. Adjusted odds ratio for lifetime diagnosis of DSM-IV major depressive disorder (2.57, 95% confidence interval [1.33, 4.96]), panic disorder (18.9 [4.72, 75.9]) and posttraumatic stress disorder (3.76 [1.32, 10.7]) suggest strong association between RLS and DSM-IV depression and anxiety disorders.

CONCLUSIONS

Prevalence of RLS estimated based on the IRLSSG diagnostic criteria is substantially lower in South Korea than in Western countries. Differences in culture and risk factors that affect the expression of RLS may vary across the countries.

Factors contributing to the development of restless legs syndrome in patients with Parkinson disease

Although restless legs syndrome (RLS) commonly accompanies Parkinson disease (PD), the mechanism of RLS development in PD is still unclear. We investigated the prevalence of RLS in Korean patients with PD, and the possible contributing factors to the development of RLS in those patients. Four hundred forty-seven consecutive patients with PD were interviewed and examined. Among them, 73 patients (16.3%) were diagnosed with RLS. PD patients with RLS had a longer duration of PD symptoms, more severe PD disability, a greater degree of cognitive decline, and a longer duration of antiparkinson therapy than those without RLS. Multivariate logistic regression analysis revealed that the duration of antiparkinson therapy was the most significant factor contributing to the development of RLS in patients with PD. The present results support a higher prevalence of RLS in patients with PD and suggest that long-term antiparkinson therapy, rather than PD itself, may contribute to the development of RLS.

Prevalence, comorbidities and risk factors of restless legs syndrome in the Korean elderly population - results from the Korean Longitudinal Study on Health and Aging

The aim of this study was to determine the prevalence, neuropsychiatric comorbidities, iron metabolism and potential risk factors of restless legs syndrome (RLS) in the elderly Korean population. As a community-based epidemiological study, a simple random sample of 1118 was drawn from a roster of 61 730 adult individuals aged 65 years and older and 714 participated. The diagnosis of RLS was established in face-to-face interviews using the four minimal diagnostic criteria for RLS recommended by National Institute of Health. Depressive symptoms, nocturnal sleep disturbances, daytime sleepiness and quality of life were evaluated. Laboratory tests of iron metabolism, markers of inflammation, renal and endocrine function, hormones and vitamins were performed. A total of 59 patients (42 women and 17 men) were diagnosed as RLS with a prevalence of 8.3% (95% confidence interval: 6.2-10.3%), with an almost twofold higher prevalence in women (10.2%) than in men (5.7%). Depression was more prevalent among the subjects with RLS than without RLS and poor nocturnal sleep and quality of life were also observed in subjects with RLS. Daytime sleepiness was observed in 32.8% of subjects with RLS. No significant differences were found in iron metabolism or other risk factors between the subjects with and without RLS. The prevalence of RLS in the Korean elderly population was comparable with that in the Caucasian population. RLS had undesirable effects on mood, sleep quality and general wellbeing of elderly individuals.

[Epidemiology of restless legs syndrome]

INTRODUCTION

Restless legs syndrome (RLS) is a chronic sensorimotor disorder where patients complain of an almost irresistible urge to move their legs. This urge can often be accompanied by pain or other unpleasant sensations, it either occurs or worsens with rest particularly at night, and improves with activity. The International Restless Legs Syndrome Study Group has established four essential criteria for clinical diagnosis of RLS.

STATE OF ART

Affecting an estimated 7.2 to 11.5% of the adult population, the symptoms of RLS may be associated with significant sleep disturbance and may have a negative impact on quality of life. The prevalence of RLS increases with age, and women are more frequently affected than men. In France, the estimated prevalence is 8.5%. Among sufferers, 4.4% complain of very severe symptoms. Although RLS is mainly idiopathic, several clinical conditions have been associated with it, especially iron deficiency with or without anemia, end-stage renal disease and pregnancy. These conditions may share a common pathophysiological mechanism involving a disorder of iron metabolism. By contrast, controversy persists as to whether polyneuropathy, particularly when associated with diabetes, is to be considered as an important cause of secondary RLS. This association is difficult to demonstrate as conventional electromyography is not adequate to detect small fiber neuropathy often associated with diabetes.

CONCLUSION AND PERSPECTIVES

RLS is often underdiagnosed and few subjects receive recommended RLS drug treatment. There is a clear need for complementary education to improve the accurate diagnosis of RLS. Indeed, better knowledge of this syndrome is a prerequisite to prompt an appropriate therapeutic management.

Epidemiology of insomnia in korean adults: prevalence and associated factors

Background and purpose

Insomnia is a common complaint in adults. However, large epidemiologic studies of insomnia involving Asian populations are rarely reported. We performed an epidemiologic study of insomnia in a large Korean adult population.

Methods

A total of 5,000 subjects (2,470 men and 2,530 women) were interviewed by telephone. A representative sample of subjects aged 20 to 69 years was constituted according to a stratified, multistage random sampling method. Insomnia was defined as either any difficulty getting to sleep or getting back to sleep after waking in the night.

Results

More than one fifth (n=1,141, 22.8%) of the 5,000 subjects complained of insomnia, with the prevalence being significantly higher in women (25.3%) than in men (20.2%, p<0.001). Logistic regression revealed that the prevalence of insomnia increased significantly with age (p<0.001), being higher in those aged 60-69 years than in those aged 20-29 years (OR=2.368, 95% CI=1.762-3.182, p<0.001), and was lower in those with a monthly income of >4.5 million Korean won than in those with an income of <1.5 million Korean won (OR=0.689, 95% CI=0.523-0.906, p<0.01).

Conclusions

Insomnia is a common complaint in Korean adults, and its prevalence is similar to that in adults in Western countries.

The four diagnostic criteria for Restless Legs Syndrome are unable to exclude confounding conditions ("mimics")

BACKGROUND

Epidemiological survey studies have suggested that a large fraction of the adult population, from five to more than 10%, have symptoms of Restless Legs Syndrome (RLS). Recently, however, it has become clear that the positive predictive value of many questionnaire screens for RLS may be fairly low and that many individuals who are identified by these screens have other conditions that can "mimic" the features of RLS by satisfying the four diagnostic criteria. We noted the presence of such confounders in a case-control family study and sought to develop methods to differentiate them from true RLS.

METHODS

Family members from the case-control study were interviewed blindly by an RLS expert using the validated Hopkins telephone diagnostic interview (HTDI). Besides questions on the four key diagnostic features of RLS, the HTDI contains open-ended questions on symptom quality and relief strategies and other questions to probe the character of provocative situations and modes of relief. Based on the entire HDTI, a diagnosis of definite, probable or possible RLS or Not-RLS was made.

RESULTS

Out of 1255 family members contacted, we diagnosed 1232: 402 (32.0%) had definite or probable RLS, 42 (3.3%) possible RLS, and 788 (62.8%) Not-RLS. Of the 788 family members who were determined not to have RLS, 126 could satisfy all four diagnostic criteria (16%). This finding indicates that the specificity of the four criteria was only 84%. Those with mimic conditions were found to have atypical presentations whose features could be used to assist in final diagnosis.

CONCLUSION

A variety of conditions, including cramps, positional discomfort, and local leg pathology can satisfy all four diagnostic criteria for RLS and thereby "mimic" RLS by satisfying the four diagnostic criteria. Definitive diagnosis of RLS, therefore, requires exclusion of these other conditions, which may be more common in the population than true RLS. Short of an extended clinical interview and workup, certain features of presentation help differentiate mimics from true RLS.