Risk Of Restless Legs Syndrome Research Articles

Fibroblast Growth Factor-23 (FGF-23) in Patients with Regular Hemodialysis: A Risk Factor for Restless Legs Syndrome

Background: Restless Legs Syndrome (RLS) is one of the most common sleep disturbance problems in dialysis patients. In this study, we would like to explore some of bone and mineral marker disorder especially fibroblast growth factor-23 (FGF-23)and its correlation with RLS in regular hemodialysis patients. Methods: This is a cross sectional study design involving 71 respondents with chronic kidney disease that already had regular hemodialysis at Haji Adam Malik Hospital Medan. Status of RLS in this patients were being evaluated according to the International Restless Leg Syndrome Study Group (IRLSG) by interviewing and laboratory examination of FGF-23, hemoglobin (Hb), serum iron (SI), total iron binding capacity (TIBC), transferrin saturation (TSAT), serum ferritin, calcium (Ca) and phosphate (P) level. Results: Of all study subjects, 26 respondents (34.6%) diagnosed with RLS. Bivariate analysis result showed that there is a relationship between FGF-23, hemoglobin, phosphate, and transferrin saturation level with RLS. Logistic regression analysis used to see the most dominant factor of all. Conclusion This study conclude that increase in FGF-23 levels can increase the risk of RLS. However, FGF-23 is not the most dominant risk factor for RLS in regular hemodialysis patients.

BTBD9 and dopaminergic dysfunction in the pathogenesis of restless legs syndrome.

Restless legs syndrome (RLS) is characterized by an urge to move legs, usually accompanied by uncomfortable sensations. RLS symptoms generally happen at night and can be relieved by movements. Genetic studies have linked polymorphisms in BTBD9 to a higher risk of RLS. Knockout of BTBD9 homolog in mice (Btbd9) and fly results in RLS-like phenotypes. A dysfunctional dopaminergic system is associated with RLS. However, the function of BTBD9 in the dopaminergic system and RLS is not clear. Here, we made use of the simple Caenorhabditis elegans nervous system. Loss of hpo-9, the worm homolog of BTBD9, resulted in hyperactive egg-laying behavior. Analysis of genetic interactions between hpo-9 and genes for dopamine receptors (dop-1, dop-3) indicated that hpo-9 and dop-1 worked similarly. Reporter assays of dop-1 and dop-3 revealed that hpo-9 knockout led to a significant increase of DOP-3 expression. This appears to be evolutionarily conserved in mice with an increased D2 receptor (D2R) mRNA in the striatum of the Btbd9 knockout mice. Furthermore, the striatal D2R protein was significantly decreased and Dynamin I was increased. Overall, activities of DA neurons in the substantia nigra were not altered, but the peripheral D1R pathway was potentiated in the Btbd9 knockout mice. Finally, we generated and characterized thedopamine neuron-specific Btbd9 knockout mice and detected anactive-phase sleepiness, suggesting that dopamine neuron-specific loss of Btbd9 is sufficient to disturb the sleep. Our results suggest that increased activities in the D1R pathway, decreased activities in the D2R pathway, or both may contribute to RLS.

The Role of BTBD9 in the Cerebellum, Sleep-like Behaviors and the Restless Legs Syndrome

Recent genome-wide association studies (GWAS) have found cerebellum as a top hit for sleep regulation. Restless legs syndrome (RLS) is a sleep-related sensorimotor disorder characterized by uncomfortable sensations in the extremities, generally at night, which are often relieved by movements. Clinical studies have found that RLS patients have structural and functional abnormalities in the cerebellum. However, whether and how cerebellar pathology contributes to sleep regulation and RLS is not known. GWAS identified polymorphisms in BTBD9 conferring a higher risk of sleep disruption and RLS. Knockout of the BTBD9 homolog in mice (Btbd9) and fly results in motor restlessness and sleep disruption. We performed manganese-enhanced magnetic resonance imaging on the Btbd9 knockout mice and found decreased neural activities in the cerebellum, especially in lobules VIII, X, and the deep cerebellar nuclei. Electrophysiological recording of Purkinje cells (PCs) from Btbd9 knockout mice revealed an increased number of non-tonic PCs. Tonic PCs showed increased spontaneous activity and intrinsic excitability. To further investigate the cerebellar contribution to RLS and sleep-like behaviors, we generated PC-specific Btbd9 knockout mice (Btbd9 pKO) and performed behavioral studies. Btbd9 pKO mice showed significant motor restlessness during the rest phase but not in the active phase. Btbd9 pKO mice also had an increased probability of waking at rest. Unlike the Btbd9 knockout mice, there was no increased thermal sensation in the Btbd9 pKO. Our results indicate that the Btbd9 knockout influences the PC activity; dysfunction in the cerebellum may contribute to the motor restlessness found in the Btbd9 knockout mice.

Selective serotonin reuptake inhibitors and the risk of restless legs syndrome: a symmetry analysis.

Largely based on case series, several drugs have been implicated in drug-induced restless legs syndrome (RLS) including selective serotonin reuptake inhibitors (SSRI). We aimed to assess the association between initiation of SSRIs and RLS in a self-controlled design. We conducted a symmetry analysis, including Danish adults who filled in their first prescription of an SSRI in the period of 1997-2017 and initiated an RLS drug (quinine, ropinirole, pramipexole or rotigotine) 1year prior to or after this date. A symmetrical distribution of prescriptions before and after SSRI initiation is expected if there is no association between SSRI and RLS (a sequence ratio (SR) of 1.0). The symmetry analysis design is robust to confounders that are stable over time. Subgroup analyses were conducted, restricting the population on sex, age, selected diagnoses and concurrent medication. A total of 10,875 patients filled in their first-ever prescription of both an SSRI and an RLS drug within a 1-year interval; 5341 patients filled their prescription of SSRI prior to their prescription of an RLS drug, and 5534 patients redeemed their prescriptions in the opposite order (SR 0.97, 95% CI 0.93-1.00). Restricting the outcome to dopamine agonist initiation revealed a slightly increased sequence ratio (SR 1.34, 95% CI 1.24-1.46), which was reduced when adjusting for trends in prescription (adjusted SR 1.21, 95% CI 1.12-1.32). Restricting the outcome to quinine initiation showed no association. We found no association between the initiation of an SSRI and the development of RLS assessed by the prescription of an RLS drug.

Acute post-stroke restless legs syndrome: the body of caudate nucleus considerations

ObjectivesTo investigate the relationship between the lesion location and post-stroke restless legs syndrome (RLS). MethodsA total of 376 patients with acute cerebral infarction were recruited from Tangshan Gongren Hospital, Department of Neurology between May 2016 and May 2017, all of whom were evaluated for RLS. Established RLS was diagnosed according to the criteria of the International Restless Legs Syndrome Study Group (IRLSSG) in 2012. Neurological functions were assessed according to the National Institutes of Health Stroke Scale (NIHSS). The lesion location was evaluated with magnetic resonance imaging (MRI). The associations between the lesion location and post-stroke RLS were then analyzed by logistic regression. ResultsA total of 49 patients (13.03%) had RLS. The multivariate logistic regression model adjusting for post-stroke RLS risk factors including gender, age, history of hypertension, history of diabetes, history of stroke, smoking, drinking, body mass index (BMI), NIHSS, hemoglobin, platelet and homocysteine determined that body of caudate nucleus and pontine were significantly associated with post-stroke RLS with odds ratio (OR) of 26.26 (95% confidence interval (CI): 9.41–73.28,p < 0.001) and OR of 4.37 (95% CI: 1.24–15.34, p = 0.021). The stepwise logistic regression model with temporal lobe, parietal lobe, occipital lobe, frontal lobe, callosum, body of caudate nucleus, thalamus, lenticulo capsule, corona radiata, centrum semi-ovale and pontine as potential predictors yielded a predictor mode. The stepwise logistic regression predictor mode indicated that body of caudate nucleus and pontine predicted post-stroke RLS with similar OR to multivariate models of 23.61 (95% CI: 9.53–58.51, p < 0.001) and 4.46 (95% CI: 1.38–14.4, p = 0.012). ConclusionsThe ischemic infarcts located in body of caudate nucleus, pontine are significantly associated with post-stroke RLS. Body of caudate nucleus acute infarcts may play a role in the development of post-stroke RLS.

Risk factors for restless legs syndrome in hemodialysis patients in Taiwan: A case-control study.

Restless legs syndrome (RLS) increases the risks of cardiovascular disease and death in hemodialysis (HD) patients. Previous studies of risk factors for RLS in HD patients have yielded varying results. We attempted to identify risk factors for RLS in HD patients in Taiwan.This case–control study recruited 59 HD patients with RLS and 353 HD patients without RLS from the largest HD center in Taiwan during the period from April 1, 2015 through August 31, 2015. Demographic and disease characteristics, information from the International Restless Legs Syndrome Study Group (IRLSSG) diagnostic questionnaire, and IRLSSG Severity Scale scores were collected by interview. Clinical laboratory data were abstracted from medical records and then analyzed with logistic regression and Pearson correlation analysis. A P value of less than .05 was considered to indicate statistical significance.A dialysis duration of longer than 5 years (odds ratio [OR] = 2.32; 95% CI = 1.23–4.39; P = .002) and a low high-density lipoprotein cholesterol level (<40 mg/dL in men; <50 mg/dL in women) (OR = 2.73; 95% CI = 1.44–5.15; P = .009) were associated with increased risk of RLS. Among the 59 patients with RLS, 48 (81.3%) had moderate or severe symptoms (IRLSSG Severity Scale >10), and RLS severity was significantly correlated with dialysis duration (r = .26; P = .043).Among HD patients, RLS was more common among those receiving dialysis for longer than 5 years and those with a low serum high-density lipoprotein cholesterol (HDL-C) level.

The role of BTBD9 in the cerebral cortex and the pathogenesis of restless legs syndrome

Restless legs syndrome (RLS) is a nocturnal neurological disorder affecting up to 10% of the population. It is characterized by an urge to move and uncomfortable sensations in the legs which can be relieved by movements. Mutations in BTBD9 may confer a higher risk of RLS. We developed Btbd9 knockout mice as an animal model. Functional alterations in the cerebral cortex, especially the sensorimotor cortex, have been found in RLS patients in several imaging studies. However, the role of cerebral cortex in the pathogenesis of RLS remains unclear. To explore this, we used in vivo manganese-enhanced MRI and found that the Btbd9 knockout mice had significantly increased neural activities in the primary somatosensory cortex (S1) and the rostral piriform cortex. Morphometry study revealed a decreased thickness in a part of S1 representing the hindlimb (S1HL) and M1. The electrophysiological recording showed Btbd9 knockout mice had enhanced short-term plasticity at the corticostriatal terminals to D1 medium spiny neurons (MSNs). Furthermore, we specifically knocked out Btbd9 in the cerebral cortex of mice (Btbd9 cKO). The Btbd9 cKO mice showed a rest-phase specific motor restlessness, decreased thermal sensation, and a thinner S1HL and M1. Both Btbd9 knockout and Btbd9 cKO exhibited motor deficits. Our results indicate that systematic BTBD9 deficiency leads to both functional and morphometrical changes of the cerebral cortex, and an alteration in the corticostriatal pathway to D1 MSNs. Loss of BTBD9 only in the cerebral cortex is sufficient to cause similar phenotypes as observed in the Btbd9 complete knockout mice.

Rotigotine suppresses sleep-related muscle activity augmented by injection of dialysis patients\u2019 sera in a mouse model of restless legs syndrome

Idiopathic restless legs syndrome (RLS) has a genetic basis wherein BTBD9 is associated with a higher risk of RLS. Hemodialysis patients also exhibit higher rates of RLS compared with the healthy population. However, little is known about the relationship of BTBD9 and end-stage renal disease to RLS pathophysiology. Here we evaluated sleep and leg muscle activity of Btbd9 mutant (MT) mice after administration of serum from patients with either idiopathic or RLS due to end-stage renal disease (renal RLS) and investigated the efficacy of treatment with the dopamine agonist rotigotine. At baseline, the amount of rapid eye movement (REM) sleep was decreased and leg muscle activity during non-REM (NREM) sleep was increased in MT mice compared to wild-type (WT) mice. Wake-promoting effects of rotigotine were attenuated by injection of serum from RLS patients in both WT and MT mice. Leg muscle activity during NREM sleep was increased only in MT mice injected with serum from RLS patients of ideiopatic and renal RLS. Subsequent treatment with rotigotine ameliorated this altered leg muscle activity. Together these results support previous reports showing a relationship between the Btbd9/dopamine system and RLS, and elucidate in part the pathophysiology of RLS.

MEIS1 and Restless Legs Syndrome: A Comprehensive Review

Restless legs syndrome (RLS) is a common sleep-related disorder for which the underlying biological pathways and genetic determinants are not well understood. The genetic factors so far identified explain less than 10% of the disease heritability. The first successful genome-wide association study (GWAS) of RLS was reported in 2007. This study identified multiple RLS associated risk variants including some within the non-coding regions of MEIS1. The MEIS1 GWAS signals are some of the strongest genetic associations reported for any common disease. MEIS1 belongs to the homeobox containing transcriptional regulatory network (HOX). Work in C. elegans showed a link between the MEIS1 ortholog and iron homeostasis, which is in line with the fact that central nervous system (CNS) iron insufficiency is thought to be a cause of RLS. Zebrafish and mice have been used to study the MEIS1 gene identifying an RLS-associated-SNP dependent enhancer activity from the highly conserved non-coding regions (HCNR) of MEIS1. Furthermore, this gene shows a lower expression of mRNA and protein in blood and thalamus of individuals with the MEIS1 RLS risk haplotype. Simulating this reduced MEIS1 expression in mouse models resulted in circadian hyperactivity, a phenotype compatible with RLS. While MEIS1 shows a strong association with RLS, the protein's function that is directly linked to an RLS biological pathway remains to be discovered. The links to iron and the enhancer activity of the HCNRs of MEIS1 suggest promising links to RLS pathways, however more in-depth studies on this gene's function are required. One important aspect of MEIS1's role in RLS is the fact that it encodes a homeobox containing transcription factor, which is essential during development. Future studies with more focus on the transcriptional regulatory role of MEIS1 may open novel venues for RLS research.

The Role of BTBD9 in Striatum and Restless Legs Syndrome.

Restless legs syndrome (RLS) is a sensory-motor neurological disorder characterized by uncomfortable sensations in the extremities, generally at night, which is often relieved by movements. Genome-wide association studies (GWAS) have identified mutations in BTBD9 conferring a higher risk of RLS. Knockout of the BTBD9 homolog in mice (Btbd9) and fly results in motor restlessness and sleep disruption. Clinical studies have found RLS patients have structural and functional abnormalities in the striatum; however, whether and how striatal pathology contributes to the pathogenesis of RLS is not known. Here, we used fMRI to map regions of altered synaptic activity in basal ganglia of systematic Btbd9 knock-out (KO) mice. We further dissected striatal circuits using patch-clamp electrophysiological recordings in brain slices. Two different mouse models were generated to test the effect of specific knockout of Btbd9 in either striatal medium spiny neurons (MSNs) or cholinergic interneurons (ChIs) using the electrophysiological recording, motor and sensory behavioral tests. We found that Btbd9 KO mice showed enhanced neural activity in the striatum, increased postsynaptic currents in the MSNs, and decreased excitability of the striatal ChIs. Knocking out Btbd9 specifically in the striatal MSNs, but not the ChIs, led to rest-phase specific motor restlessness, sleep disturbance, and increased thermal sensation in mice, which are consistent with results obtained from the Btbd9 KO mice. Our data establish the role of Btbd9 in regulating the activity of striatal neurons. Increased activity of the striatal MSNs, possibly through modulation by the striatal ChIs, contributes to the pathogenesis of RLS.

Use of antidepressants and risks of restless legs syndrome in patients with irritable bowel syndrome: A population-based cohort study.

Previous research has suggested an association between antidepressants use and clinical restless legs syndrome (RLS) in patients, but there has never been a single study investigating the risk of RLS in irritable bowel syndrome (IBS) patients treated with antidepressants. Hence, we aimed to explore the association between IBS and RLS and to examine the risk of RLS in IBS patients treated with antidepressants. With the use of the National Health Insurance Research Database of Taiwan, 27,437 adults aged ≥ 20 years with newly diagnosed IBS (ICD-9-CM Code 564.1) and gender- and age-matched 54,874 controls without IBS were enrolled between 2000 and 2012. All patients were followed-up until RLS diagnosis, withdrawal from the National Health Insurance program, or end of 2013. We used the Cox proportional hazards model to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) of RLS. RLS was more prevalent in IBS patients than in the non-IBS group (7.57 versus 3.36 per 10,000 person-years), with an increased risk of RLS (adjusted HR [aHR], 1.91; 95% CI, 1.52–2.40). Multivariate Cox proportional hazards analysis identified older age (age, 51–65 years; aHR, 1.67; 95% CI, 1.09–2.56; and age > 65; aHR, 1.59; 95% CI, 1.02–2.48), hypothyroidism (aHR, 4.24; 95% CI, 1.92–9.37), CAD (aHR, 1.70; 95% CI, 1.17–2.48), and depression (aHR, 3.15; 95% CI, 2.14–4.64) as independent RLS risk factors in IBS patients. In addition, the male SSRIs users were associated with significantly higher risk of RLS (aHR, 3.05 95% CI, 1.34–6.92). Our study showed that the IBS group has higher risk of RLS. Moreover, SSRIs use may increase the risk of RLS in male IBS patients.

Genetic Association Study of Restless Legs Syndrome in Chinese Population

Backgrounds: Several recent case-control studies have suggested some candidate genes being responsible for causing the restless legs syndrome (RLS). However, the association between those genes and the risk for RLS among the Asian population has not been well investigated. Objectives: The aim of the study was to investigate the genetic risk factors of RLS among the Chinese Population. Methods: A total of 158 RLS patients and 229 controls were recruited and the diagnosis of RLS was based on the criteria of International RLS Study Group. Polymer chain reaction and sequencing were used to detect 14 single nucleotide polymorphisms (SNPs) in 9 genetic loci (heme oxygenase 1 [HMOX1], HMOX2, vitamin D3 [1, 25-dihydroxyvitamin D3] receptor gene [VDR], interleukin 17A [IL17A], IL1B, NOS1, alcohol-dehydrogenase [ADH1B], gamma-aminobutyrate acid receptors[GABRR3] and GABRA4). Results: Among 14 selected SNPs, the frequency of IL1B rs1143634C allelic variant was lower in RLS patients than that in controls. Moreover, after adjustment for age and sex, rs731236 of VDR were found associated with increased risk of RLS in the dominant model. However, none of those results survived Bonferroni correction. The effects of HMOX1 and HMOX2 gene on developing RLS were not seen after the inclusion of RLS patients with a low ferritin level. Conclusions: Our study failed to replicate the association between 9 candidate genetic loci (HMOX1, HMOX2, VDR, IL17A, IL1B, NOS1, ADH1B, GABRR3 and GABRA4) and RLS in the Chinese population.

Restless legs syndrome in end stage renal disease patients undergoing hemodialysis

BackgroundThe prevalence of Restless legs syndrome (RLS) in End Stage Renal Disease (ESRD) patients is higher than that in the general population. However, the associations of RLS within the ESRD population are inconsistent and RLS is usually neglected in dialysis centers, although it impairs the life quality among ESRD patients. We aim to investigate the prevalence of RLS in patients with ESRD undergoing maintenance hemodialysis and evaluate the risk factors of developing RLS and the effect of RLS on quality of life among ESRD patients.MethodsESRD patients undergoing maintenance hemodialysis in Shanghai General Hospital dialysis unit from July 2016 to October 2016 were enrolled in the study. RLS was diagnosed according to the criteria of the International Restless Legs Syndrome Study Group (IRLSSG). IRLSSG Severity Scale was used to evaluate the severity of RLS. Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality, and Hospital Anxiety and Depression Scale (HADS) was used to estimate anxiety and depression. Serologic and historic variables were analyzed to determine predictors of RLS in the ESRD population.ResultsA total of 137 ESRD patients were enrolled. The prevalence of RLS among the ESRD patients was 20.44%. The risk of RLS was increased significantly in females (OR = 2.729, p = 0.032) and daily alcohol drinkers (OR = 4.716, p = 0.022). RLS increased the risks of sleep disorders (25/28, 89.3% vs 73/109, 67.0%, p = 0.02) and sedative hypnotics intake (7/28, 25.0% vs 10/109, 9.2%, p = 0.047) and impaired the sleep quality (7/109 vs 11/28, p = 0.001) according to PSQI sum scores.ConclusionA high RLS prevalence among the ESRD patients undergoing hemodialysis was confirmed. ESRD patients who are women and drinking alcohol have a higher risk of RLS. The sleep quality was significantly impaired and sleeping medication use was more common among the ESRD patients with RLS.

A sleep apnoea questionnaire predicts organ damage in hypertensive patients

Background: Arterial hypertension is associated with obstructive sleep apnoea, poor quality and duration of sleep, which might contribute to hypertension-mediated organ damage.Methods: We investigated the presence of insomnia, restless legs syndrome, and obstructive sleep apnoea using validated questionnaires (Insomnia Severity Index, Restless Legs Syndrome Rating Scale, and STOP-Bang), and their relationship with hypertension-mediated organ damage, in hypertensive patients.Results: In 159 consecutive consenting hypertensive patients [age 47(11) years, median and (interquartile range), body mass index 25.5(5.9) kg/m2, office systolic and diastolic blood pressure 144(23)/92(12) mmHg], the STOP-Bang, but not the other scores, predicted cardiac remodelling: compared to patients with a STOP-Bang score < 3, those at high risk of obstructive sleep apnoea showed higher left ventricular mass index [49.8(11.9) vs. 43.3(11.9) g/m2.7, p < 0.0001], left atrium volume [25.7(2.5) vs. 25.0(2.8) ml/m2, p = 0.003], and aortic root diameter [33.6(3.0) vs. 33.0(3.7) mm, p < 0.0001]. They did not differ for microalbuminuria and estimated glomerular filtration rate. At multivariate analysis, after adjustment for office systolic blood pressure values, the STOP-Bang score remained a predictor of left ventricular mass index; while the Insomnia Severity Index and restless legs syndrome risk score had no predictive value. However, a significant interaction between STOP-Bang and Restless Legs Syndrome Rating Scale scores in determining left ventricular remodelling was found.Conclusions: In consecutive hypertensive stage I patients the STOP-Bang questionnaire allowed identification of a high-risk cohort featuring a more prominent cardiac damage. Hence, this inexpensive tool can be useful for risk stratification purposes in municipalities with limited access to health care resources.

Restless Legs Syndrome/Willis-Ekbom Disease in Multiple Sclerosis Patients with Spinal Cord Lesions.

Spinal cord lesions in Multiple Sclerosis (MS) patients are associated with a higher risk of restless legs syndrome (RLS). In this study, we investigated the prevalence of RLS, sleep quality, presence and severity of depression, and the relationship of these parameters with cervical cord lesions in patients with RRMS. This study was conducted in the outpatient multiple sclerosis clinic of Marmara University Hospital between October 2013 - February 2014, including 93 patients with the diagnosis of MS. After signing informed consent, demographic data, comorbidities and actual medication of the patients were collected. All patients completed the surveys including Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and Beck Depression Inventory (BDI). Prevalence of HBS, sleep quality and depression severity were compared between those with and without cervical cord lesions. Furthermore, the relationship between RLS and sleep quality, depression and expanded disability status scale (EDSS) was assessed. From overall patients, 72% were women (n=67) and 28% (n=26) were men. From all subjects, 32% (n=30) fulfilled IRLSSG diagnostic criteria. Fifty-seven percent of the patients (n=53) had pathological spinal cord lesions. Patients with RLS had significantly higher prevalence of pathological spinal cord lesions compared to patients without RLS (p=0.04). Sleep quality was found to be poor in both patients with cervical cord lesions and patients with RLS and this was statistically significant (p=0.031, p=0.0001). In summary, the possibility of RLS development in RRMS patients increases with the presence of lesions in spinal cord. Sleep quality was found to be poor in both patients with cervical cord lesions and patients with RLS. As RLS is a potentially treatable condition, increased awareness of diagnosis of RLS in MS patients may be important for early treatment and improve the comfort of the patient.

Caenorhabditis elegans and its applicability to studies on restless legs syndrome.

Restless legs syndrome (RLS) is a common neurological disorder in the United States. This disorder is characterized by an irresistible urge to move the legs, although the symptoms vary in a wide range. The pathobiology of RLS has been linked to iron (Fe) deficiency and dopaminergic (DAergic) dysfunction. Several genetic factors have been reported to increase the risk of RLS. Caenorhabditis elegans (C. elegans) is a well-established animal model with a fully sequenced genome, which is highly conserved with mammals. Given the detailed knowledge of its genomic architecture, ease of genetic manipulation and conserved biosynthetic and metabolic pathways, as well as its small size, ease of maintenance, speedy generation time and large brood size, C. elegans provides numerous advantages in studying RLS-associated gene-environment interactions. Here we will review current knowledge about RLS symptoms, pathology and treatments, and discuss the application of C. elegans in RLS study, including the worm homologous genes and methods that could be performed to advance the pathophysiology RLS.

Prevalence of restless legs syndrome in individuals with migraine: a systematic review and meta-analysis of observational studies.

Recent studies have shown an association between migraine and restless legs syndrome (RLS), but RLS prevalence among individuals with migraine differs substantially across studies. The present work aimed to comprehensively assess available evidence to estimate RLS prevalence among individuals with migraine and non-migraine controls. Web of Science, PubMed, Embase, Chinese National Knowledge Infrastructure, Wanfang, and SinoMed databases were searched for observational and case-control studies of RLS prevalence among individuals with migraine. Eligible studies were meta-analyzed using Stata 12.0 software. Pooled RLS prevalence in migraine was 19%, and the prevalence was lower in Asia (16%) than outside Asia (21%). Pooled RLS prevalence was 18.8% among individuals with migraine with aura, and 18.5% among individuals with migraine without aura; the RLS prevalence in migraine with aura (MA) was higher than that of migraine without aura (MO) (OR 1.17, 95%CI 1.01-1.34; p = 0.037). Pooled RLS prevalence in a case-control study was significantly higher among individuals with migraine (17.9%) than among non-migraine controls (7.1%) (OR 2.65, 95%CI 2.26-3.10; p < 0.001). Our meta-analysis provides the first reliable pooled estimate of RLS prevalence among individuals with migraine, and it provides strong evidence that RLS risk is higher among individuals with migraine than among controls.

Systematic review and meta-analysis of observational studies to understand the prevalence of restless legs syndrome in multiple sclerosis: an update

ObjectiveMultiple sclerosis (MS) is related to the demyelination of intracranial nerves at multiple sites, while restless legs syndrome (RLS) appears to be caused by dysfunction of the dopaminergic system. Since RLS prevalence is higher among MS patients than in the general population, we carried out an updated meta-analysis to understand whether the two diseases might be associated. MethodWeb of Science, PubMed, Embase, Chinese National Knowledge Infrastructure, Wanfang, and SinoMed databases were searched for observational and case-controlled studies of RLS prevalence in MS. Eligible studies were meta-analyzed using Stata 12.0. ResultsPooled RLS prevalence among MS patients of various ethnicities was 26%, and prevalence was lower in Asia (20%) than outside Asia (27%). Prevalence was higher among cross-sectional studies (30%) than among case–control studies (23%). RLS prevalence was higher among female than male MS patients (26% vs. 17%), and it was higher among MS patients than among healthy controls (OR 3.96, 95%CI 3.29–4.77, p < 0.001). ConclusionOur meta-analysis updates the most recent meta-analysis in 2013 and provides perhaps the first reliable pooled estimate of RLS prevalence in MS. The available evidence strongly suggests that RLS risk is higher among MS patients than healthy controls.

Restless Legs Syndrome Negatively Impacts Worker Health and Safety.

Restless legs syndrome (RLS) is a highly prevalent sleep disorder contributing to worker absenteeism, decline in productivity, and employer costs. Identification of workers at risk for RLS can contribute to improved worker sleep, safety, and quality of life.

Lack of Association Between Shape and Volume of Subcortical Brain Structures and Restless Legs Syndrome.

Previous studies on patients with restless legs syndrome (RLS) yielded inconclusive results in the magnetic resonance imaging (MRI)-based analyses of alterations of subcortical structures in the brain. The aim of this study was to compare volumes as well as shapes of subcortical structures and the hippocampus between RLS cases and controls. Additionally, the associations between the genetic risks for RLS and subcortical volumes were investigated. We compared volumetric as well as shape differences assessed by 3 T MRI in the caudate nucleus, hippocampus, globus pallidus, putamen, and thalamus in 39 RLS cases versus 117 controls, nested within a population-based sample. In a subsample, we explored associations between known genetic risk markers for RLS and the volumes of the subcortical structures and the hippocampus. No significant differences between RLS cases and controls in subcortical and hippocampal shapes and volumes were observed. Furthermore, the genetic risk for RLS was unrelated to any alterations of subcortical and hippocampal gray matter volume. We conclude that neither RLS nor the genetic risk for the disease give rise to changes in hippocampal and subcortical shapes and gray matter volumes.