The Association Between Vitamin D Level and Restless Legs Syndrome: A Population-Based Case-Control Study

Can restless legs be a sign of something else? A case report of spondyloarthritis presenting with restless legs syndrome and a review of the literature

Restless legs syndrome (RLS) is a chronic movement disorder characterized by an urge or need to move the limbs, usually associated with uncomfortable sensations in the legs and sleep disorders. In general, two clinical forms of RLS are described: primary and secondary. Although primary RLS has a familial component, the underlying mechanism is still not fully understood but seems to be related to abnormalities in the dopaminergic and glutamatergic pathways of the central nervous system. The secondary forms of the syndrome are associated with iron deficiency, renal failure, pregnancy, diabetes mellitus, peripheral neuropathy, and several rheumatologic disorders such as rheumatoid arthritis and Sjögren's syndrome. In a few clinical trials, an increased frequency of RLS has been reported in patients with spondyloarthritis. In this report, a case of coexistence of spondyloarthritis and RLS is presented, showing satisfactory improvement with conservative treatment and additionally adding naproxen. Anemia of chronic disease occurring in rheumatic diseases, and associated iron deficiency may contribute to the development of RLS.

The Diagnostic Workup, Screening, and Treatment Approaches for Patients with Delusional Infestation

Delusional infestation (DI) is a psychiatric disorder defined by the fixed, false belief that one has been infested by an organism without evidence to support this. Patients may present with skin lesions and report abnormal cutaneous sensations. The diagnostic workup for patients presenting with delusional infestation is essential to ensuring accurate diagnosis in ruling out other explanations for symptoms and investigating potential secondary causes of DI. In addition to a comprehensive history and physical examination, laboratory workup should be considered depending on the clinical picture. Antipsychotic medications are the most common drugs used in management of adults with DI and tailor the choice of treatment according to patient characteristics. This article serves as a guide for dermatologists, psychiatrists, and other clinicians as it reviews the workup and screening that should be considered when managing a patient with delusional infestation and subsequent treatment protocols once the diagnosis has been made.

Exploring the causes of augmentation in restless legs syndrome

Long-term drug treatment for Restless Legs Syndrome (RLS) patients can frequently result in augmentation, which is the deterioration of symptoms with an increased drug dose. The cause of augmentation, especially derived from dopamine therapy, remains elusive. Here, we review recent research and clinical progress on the possible mechanism underlying RLS augmentation. Dysfunction of the dopamine system highly possibly plays a role in the development of RLS augmentation, as dopamine agonists improve desensitization of dopamine receptors, disturb receptor interactions within or outside the dopamine receptor family, and interfere with the natural regulation of dopamine synthesis and release in the neural system. Iron deficiency is also indicated to contribute to RLS augmentation, as low iron levels can affect the function of the dopamine system. Furthermore, genetic risk factors, such as variations in the BTBD9 and MEIS1 genes, have been linked to an increased risk of RLS initiation and augmentation. Additionally, circadian rhythm, which controls the sleep-wake cycle, may also contribute to the worsening of RLS symptoms and the development of augmentation. Recently, Vitamin D deficiency has been suggested to be involved in RLS augmentation. Based on these findings, we propose that the progressive reduction of selective receptors, influenced by various pathological factors, reverses the overcompensation of the dopamine intensity promoted by short-term, low-dose dopaminergic therapy in the development of augmentation. More research is needed to uncover a deeper understanding of the mechanisms underlying the RLS symptom and to develop effective RLS augmentation treatments.

Vitamin D and Restless Legs Syndrome: A Review of Current Literature

This review presents a detailed summary of the current literature regarding RLS and vitamin D deficiency. To our knowledge it is the first review of its kind. We review the prevalence of vitamin D deficiency in RLS as well as the evidence for the use of vitamin D supplementation in RLS management. We further examine the literature for proteomic and genetic evidence of a role for vitamin D in the pathogenesis of RLS. An alteration in vitamin D binding protein in RLS is one of the most consistent findings in the proteomic studies. Furthermore, we examine the interaction of vitamin D with calcium, phosphorus, and parathyroid hormone and the possible role of these connections in RLS. We also explore the possible nexus between RLS and vitamin D in renal disease, cardiovascular and cerebrovascular disease as well as inflammation. In addition, we review the potential interaction between vitamin D and RLS with iron, dopamine and other neurotransmitter systems including the endogenous opiate, serotoninergic, glutamatergic and adenosinergic systems. We also explore the role of vitamin D in RLS Augmentation (i.e., the paradoxical worsening of RLS symptoms when dopaminergic agents are used as a therapy for RLS). Although the literature is not entirely consistent in affirming vitamin D deficiency in RLS or the amelioration of RLS symptoms with vitamin D therapy, the collective studies overall indicate that vitamin D deficiency is common enough in RLS patients to suggest that RLS patients should have their vitamin D levels checked and any deficiency corrected as a standard of care.

Highlights 

Patients with Restless Legs Syndrome (RLS) may be deficient in vitamin D and therapy with vitamin D may ameliorate RLS. We present the first review dedicated solely to evaluating the relationship between RLS and vitamin D and present a case for the role of vitamin D in RLS pathogenesis.

The prevalence and associated factors of seasonal exacerbation of subjective symptoms in Japanese patients with restless legs syndrome

OBJECTIVES

To elucidate the prevalence of seasonal exacerbation in patients with restless legs syndrome (RLS) and identify its associated factors.

METHODS

We investigated the presence/absence of seasonal exacerbation of RLS by distributing self-administered questionnaires with an interval of three years. Patients who reported having seasonal exacerbation in both surveys were defined as having seasonal exacerbation. RLS severity was determined using the International Restless Legs Syndrome Rating Scale (IRLS).

RESULTS

Among 180 patients, 89 reported having seasonal exacerbation in the first survey. Among them, only two reported not having seasonal exacerbation in the second survey; thus, 87 (48.3%) patients were considered to have a seasonal exacerbation. Although many of them (68 out of 87, 78.2%) experienced exacerbation in spring or summer, 19 out of 87 (21.8%) reported that their symptoms worsened in fall or winter. All the patients in this study had mild to moderate degrees of RLS severity according to the IRLS score. Multiple logistic regression analyses revealed that having a family history of RLS (p < 0.05) and moderate RLS (p < 0.001) were significantly associated with the presence of seasonal exacerbation.

CONCLUSIONS

This study revealed that approximately half of all RLS patients had seasonal exacerbation of the symptoms and that about 80% of the exacerbation was observed during the spring/summer season. Moreover, seasonal exacerbation is likely to be present even in patients whose symptoms had been improved to moderate severity with pharmacological treatment.

Determination of optimal 25-hydroxyvitamin D cutoff values for the evaluation of restless legs syndrome among pregnant women

STUDY OBJECTIVES

Vitamin D deficiency is associated with restless legs syndrome (RLS). However, a cutoff value for serum 25-hydroxyvitamin D (25[OH]D) level associated with RLS has yet to be clearly determined. We evaluated the association between 25(OH)D and RLS in pregnant women.

METHODS

Data from 203 pregnant women were evaluated using blood samples taken in the third trimester. Liquid chromatography-tandem mass spectrometry and ligand binding assays were used to measure 25(OH)D. RLS was diagnosed based on International Classification of Sleep Disorders, third edition, criteria. The cutoff value for serum 25(OH)D associated with RLS was explored using receiver operating characteristic (ROC) curve and classification and regression tree (CART) analyses.

RESULTS

The results of liquid chromatography-tandem mass spectrometry (x) and ligand binding assays (y) for serum 25(OH)D in the RLS (n = 35, 17.2%) and non-RLS (n = 168) groups showed a relationship of y = -2.65 + 0.08x . The RLS group showed lower serum 25(OH)D and folate levels. ROC curve and CART analyses revealed cutoff values of 10-12.7 ng/mL and 6.6-7.2 ng/mL for 25(OH)D and folate, respectively. Of the 5 women with RLS symptoms persisting at a moderate-to-severe level after delivery, 4 had 25(OH)D levels < 10 ng/mL and all had folate levels < 6 ng/mL.

CONCLUSIONS

Vitamin D and folate deficiency were associated with RLS in pregnant women and may be associated with persistent moderate-to-severe postpartum RLS symptomatology; it is essential to examine associations with RLS while accounting for measurement methods and assay systems.

CITATION

Miyazaki A, Takahashi M, Shuo T, Eto H, Kondo H. Determination of optimal 25-hydroxyvitamin D cutoff values for the evaluation of restless legs syndrome among pregnant women. J Clin Sleep Med. 2023;19(1):73-83.

Possible etiologies of restless legs syndrome in pregnancy: a narrative review

Restless legs syndrome (RLS) is a sensorimotor disorder characterized by an urgent need to move the legs, due to the presence of a discomfort sensation in the lower limbs, especially at rest. Generally, it relieves with movement. There are several studies that argue the existence of an association between this syndrome and pregnancy. However, the pathophysiological mechanisms of this disorder in pregnancy are misunderstood. The objective of this narrative review is to identify and discuss some possible etiologies of RLS in pregnancy. A literature search was performed in the PubMed and ResearchGate databases by using the following search strategies: "restless legs syndrome", "restless legs syndrome in pregnancy", "pregnancy and vitamin D deficiency" and "pregnancy and zinc". The publications were initially sorted through their title. After the initial process, inclusion and exclusion criteria were applied. The included articles were sorted by authors, year, journal of publication, type of study, and organized by chronological order of publication. Among the main findings, hormonal changes, iron metabolism, vitamin D deficiency, genetic factors, zinc and magnesium fluctuations have been some of the hypotheses supporting the development or worsening of this disorder in pregnancy. Dopamine also appears to be correlated with hormonal changes, iron metabolism, ferritin, folic acid and vitamin D deficiency. In conclusion, there are several hypotheses trying to link restless legs syndrome with pregnancy. The most covered were hormonal fluctuations and iron metabolism. However, this thematic is still highly discussed, creating the need for additional and thorough research.

Correlation between vitamin D and poor sleep status in restless legs syndrome

BACKGROUND

Restless Legs Syndrome (RLS) is closely related to poorer sleep quality. Vitamin D can regulate sleep regulation, cell proliferation, and differentiation. To measure whether vitamin D has predictive value for poor sleep quality in RLS was our aim in this study.

METHODS

To analyze the serum levels of 25-hydroxyvitamin D [25(OH)D] in 95 RLS patients. We used the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality. Subjects had been divided into a normal and poor-sleeper groups according to the PSQI score. Using correlation and regression analysis to explore underlying etiologies that affect sleep disorder in RLS patients.

RESULTS

Patients in the poor-sleeper group had significantly lower vitamin D levels in comparison to the normal group. The serum vitamin D levels were negative correlate with PSQI scores after adjusting for confounding factors. In addition, regression analysis showed that vitamin D could act as a predictor for sleep disorders in RLS patients (odds ratio [OR] = 0.008, p = 0.004). The area under the curve (AUC), cut-off value, sensitivity, and specificity of serum vitamin D was 0.967 (95% CI 0.935-0.998), 16.84 ng/ml, 87.5%, and 93.7% by receiver operating characteristic (ROC) analysis.

CONCLUSION

Our study confirmed the relationship between poorer sleep quality and vitamin D in RLS. However, the causal relationship between vitamin D deficiency and RLS is currently inconclusive. The effect of vitamin D supplementation is needed to confirm as the therapeutic strategies for sleep disorders in RLS patients in future work.

Analysis of Serum Vitamin D Level and Related Factors in Patients With Restless Legs Syndrome

Objective: This study aimed to detect serum vitamin D (VitD) levels in patients with primary restless legs syndrome (RLS). The further objective was to analyze the relationship of VitD levels with the severity of RLS symptoms, sleep, anxiety, and depression.

Methods: The serum 25-hydroxyvitamin D [25(OH)D] levels of 57 patients with primary RLS and the healthy physical examinees in our hospital during the same period were detected. The International Restless Legs Syndrome Study Group (IRLSSG) rating scale for measuring RLS severity and Pittsburgh Sleep Quality Index (PSQI) Scale, 24-item Hamilton Depression Rating Scale (HAMD₂₄), and 14-item Hamilton Anxiety Scale (HAMA₁₄) were used to assess the severity of symptoms, sleep, and emotional state of patients with RLS. Based on VitD level and IRLSSG score, they were grouped for analysis.

Results: The serum 25(OH)D level was significantly lower in patients with RLS than in healthy controls, and the incidence of insufficient serum VitD levels was significantly higher in patients with RLS than in healthy people (both P < 0.05). The serum VitD level was significantly lower in (extremely) severe patients with RLS than in mild to moderate patients with RLS (P < 0.05). The IRLSSG scale score and HAMD₂₄ score were significantly higher in patients with RLS with insufficient serum VitD levels than those with normal serum VitD levels (both P < 0.05). Correlation analysis of IRLSSG scale score with serum VitD level and each scale score in patients with RLS showed that IRLSSG scale score was negatively correlated with VitD level, but positively correlated with PSQI, HAMA₁₄, and HAMD₂₄ scores. The results of correlation analysis between serum VitD levels and each scale score in patients with RLS indicated that serum VitD levels were negatively correlated with IRLSSG scale scores, PSQI scores, and HAMD₂₄ scores.

Conclusion: The serum VitD level is generally lower in patients with RLS than in healthy people, and lower serum VitD level is associated with more severe symptoms of RLS, worse quality of sleep, and worse depression.

Association Between Migraine Complicated With Restless Legs Syndrome and Vitamin D

Background: This study aimed to evaluate the prevalence of restless legs syndrome (RLS) in patients with migraine and explore its association with vitamin D deficiency, aiming to provide biological support for the comorbidity of migraine with RLS, and shed new lights into clinical diagnosis and treatment.

Methods: A case-control study was performed on 175 migraine patients and 151 non-headache controls. The information of all subjects concerning headache severity [visual analog scale (VAS) score], RLS, RLS severity [International Restless Legs Scale (IRLS) score], sleep quality [Pittsburgh sleep quality index (PSQI)], anxiety and depression symptoms [hospital anxiety and depression scale (HADS)], and demographic data were collected. At the same time, serum 25-(OH) D levels were also measured (concentration <20 ng/ml was defined deficiency). Afterward, the logistic regression model was adopted to explore the risk factors for RLS in patients with migraines.

Results: Compared with control group, migraine group had lower vitamin D levels [(21.10 ± 6.58) vs. (16.42 ± 5.6) ng/ml, P < 0.001], a higher rate of vitamin D deficiency (45.03 vs. 72%, P <0001), higher prevalence of RLS (6.62 vs. 22.29%, P < 0.001). Compared with the pure RLS group, RLS with the migraine group had lower vitamin D levels and higher IRLS score (P < 0.05). Compared with pure migraine group, migraine with RLS group had lower vitamin D levels [(17.36 ± 5.56) vs. (13.15 ± 4.42) ng/ml, P < 0.001], higher incidence of vitamin D deficiency (66.18 vs. 92.31%, P = 0.001), higher frequency of headache attacks (P = 0.004). Thereafter, the multivariate logistic regression model was employed to adjust confounding factors such as age, gender, season, frequency of headache attacks, PSQI score, and HADS scores. According to the results vitamin D deficiency in patients with migraines was an independent risk factor for RLS (OR = 5.03, 95%CI: 1.2–21.16, P = 0.027).

Conclusions: The prevalence of RLS in migraine patients was significantly higher than that in the non-headache population. Besides, vitamin D levels decreased, while the incidence of vitamin D deficiency increased in the migraine patients complicated with RLS. Finally, the occurrence of RLS in migraine patients was significantly related to vitamin D deficiency.

Restless Leg Syndrome and Sleep Disorders in Patients with Rheumatoid Arthritis and Its Relation with Anemia Parameters

OBJECTIVES

We aimed to investigate the prevalence of restless legs syndrome (RLS) and sleep disorders in patients with rheumatoid arthritis (RA), and the association of iron deficiency with them.

MATERIALS AND METHODS

The study included 72 patients with RA (59 females, 13 males), and 50 healthy control subjects (57 females, 15 males). Assessments were made using the International RLS Rating Scale, Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale, Fatigue Severity Scale (FSS), Beck anxiety and depression index and the SF-36 quality of life scores.

RESULTS

We found that the frequency of RLS in RA patients was 29.1% and 13.8% in healthy control (p = 0.021). RA patients had 44.4% iron deficiency and 5.5% anemia of chronic disease. We found that 52.3% of patients with iron deficiency had RLS. There was an independent relationship between present of RLS and FSS (Beta [β] = 0.317, p = 0.005) and total iron binding capacity (TIBC) (β = 0.244, p = 0.031). There was an independent relationship between RLS severity score and PSQI (β = 0.264, p = 0.025) and social functionality (β = 0.302, p = 0.009).

CONCLUSION

The prevalence of iron deficiency is high in RA in the developing countries. Analysis obtained in patients with RA is suggestive of an association between iron deficiency and increased frequency of RLS. The presence of RLS in patients with RA negatively affects sleep quality, psychiatric status, and quality of life of patients with RA. TIBC value may be a predictive marker for early detection of RLS in patients with RA.

Searching for Novel Candidate Biomarkers of RLS in Blood by Proteomic Analysis

PURPOSE

We performed comparative proteomic analyses of blood of patients with RLS and healthy individuals aiming to identify potential biomarker and therapeutic target candidate for RLS.

PATIENTS AND METHODS

Blood serum samples from 12 patients with a clinical diagnosis of RLS (8 females and 4 males, with a mean age of 68.52 years) and 10 healthy controls (5 females and 5 males, with a mean age of 67.61 years) underwent proteomic profiling by liquid chromatography coupled with tandem mass spectrometry. Pathway analysis incorporating protein-protein interaction networks was carried out to identify pathological processes linked to the differentially expressed proteins.

RESULTS

We quantified 272 proteins in patients with RLS and healthy controls, of which 243 were shared. Five proteins - apolipoprotein C-II, leucine-rich alpha-2-glycoprotein 1, FLJ92374, extracellular matrix protein 1, and FLJ93143 - were substantially increased in RLS patients, whereas nine proteins - vitamin D-binding protein, FLJ78071, alpha-1-antitrypsin, CD5 antigen-like, haptoglobin, fibrinogen alpha chain, complement factor H-related protein 1, platelet factor 4, and plasma protease C1 inhibitor - were decreased. Bioinformatics analyses revealed that these proteins were linked to 1) inflammatory and immune response, and complement activation, 2) brain-related development, cell aging, and memory disorders, 3) pregnancy and associated complications, 4) myocardial infarction, and 5) reactive oxygen species generation and subsequent diabetes mellitus.

CONCLUSION

Our findings shed light on the multifactorial nature of RLS and identified a set of circulating proteins that may have clinical importance as biomarkers and therapeutic targets.

Bidirectional association between irritable bowel syndrome and restless legs syndrome: a systematic review and meta-analysis

BACKGROUND

Several observational studies have shown that patients with irritable bowel syndrome (IBS) may have a high risk of restless legs syndrome (RLS). This systematic review and meta-analysis aimed to comprehensively investigate the bidirectional association between IBS and RLS.

METHODS

All conservational studies on IBS and RLS were searched in MEDLINE (assessed by PubMed), Embase, Web of Science, CINAHL, the Cochrane Library database and Google Scholar from inception to June 14, 2020. The Newcastle-Ottawa Scale and Agency for Healthcare Research and Quality were used to assess the methodological quality of the cohort and cross-sectional studies, respectively. The pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using Reviewer Manager 5.3.

RESULT

A total of five cross-sectional studies of moderate methodological quality and one cohort study of high methodological quality were included in our review. Four cross-sectional studies and one cohort study involving 86 438 individuals met the criteria of IBS predicating the onset of RLS. Patients with IBS had a nearly three-fold increased odds of RLS compared with controls (OR = 2.60, 95%CI: 2.17-3.12, P < 0.00001; I² = 48%, P = 0.11). Three sensitivity analyses confirmed the robustness of the pooled result. Two cross-sectional studies involving 3581 individuals met the criteria of RLS predicating the onset of IBS. RLS patients had a nearly four-fold increased odds of IBS compared with controls without RLS (OR = 3.87, 95%CI: 1.73-8.66, P = 0.0010; I² = 77%, P = 0.04).

CONCLUSION

In this systematic review and meta-analysis, we found a substantial bidirectional association between IBS and RLS. More prospective, high-quality, population-based studies are warranted in the future.

Serum vitamin D, vitamin D receptor and binding protein genes polymorphisms in restless legs syndrome

BACKGROUND/OBJECTIVES

Several studies showed lower serum 25-hydroxyvitamin D levels in patients with idiopathic restless legs syndrome (RLS) compared with matched controls, and a single study showed an association between the rs731236 single nucleotide polymorphism (SNP) in the vitamin D receptor (VDR) gene and the risk for RLS. We aimed to study the relationship between the serum 25-hydroxyvitamin D levels and to confirm previous findings related to SNPs in the VDR and the GC vitamin D binding protein (GC) gene, with the risk for RLS in the Spanish Caucasian population.

METHODS

We genotyped 285 idiopathic RLS patients and 325 age and sex-matched controls for VDRrs2228750, VDRrs7975232, VDRrs739837, VDRrs78783628, GCrs7041 and GCrs4588 SNPs using TaqMan assays, and determined serum 25-hydroxyvitamin D levels in 111 idiopathic RLS patients and 167 controls using an ELISA commercial kit.

RESULTS

Serum 25-hydroxyvitamin D levels were significantly higher in RLS patients than in controls but were unrelated with the 7 SNPs studied. None of the 7 SNPs analyzed was associated with the risk for idiopathic RLS or with a positive family history of RLS. However, RLS patients carrying the rs7975232CC genotype or the rs7975232C allele, had a higher frequency of response to GABAergic drugs. Associations between the age at onset and the severity of RLS with SNPs were inconsistent.

CONCLUSIONS

This study shows an association between increased serum concentrations of 25-hydroxyvitamin D and a lack of association between 7 SNPs in the VDR and in the GC genes with RLS in the Spanish Caucasian population.

A meta-analysis: Does vitamin D play a promising role in sleep disorders?

BACKGROUND

Sleep disorders, one of the most common problems in the general population, have been related to a series of harmful health consequences. Vitamin D appears to be associated with sleep disorders. However, the difference in vitamin D levels between sleep disorder subjects and people without a sleep disorder is unclear. Simultaneously, the influence of vitamin D replenishment on sleep disorders remains controversial.

METHODS

PubMed, MEDLINE, Web of Science, and Cochrane Library were searched for literatures published until October 2019. Using a random effects model, a meta-analysis was conducted to calculate the standard mean difference to evaluate the difference in vitamin D concentrations between sleep disorder subjects and normal people and the efficacy of vitamin D supplementation on sleep disorders.

RESULTS

Our study found that the serum vitamin D levels in the sleep disorder subjects were lower than that in the normal people (SMD = -0.75 ng/ml, 95% CI = -0.93, -0.57 ng/ml). Moreover, the Pittsburgh Sleep Quality Index (PSQI)in the subjects with vitamin D supplementation was lower than that in the controls (SMD = -0.45, 95% CI = -0.76, -0.13).

CONCLUSIONS

Vitamin D could play a promising role in sleep disorders. More data are required to confirm the efficacy of vitamin D supplementation for improving sleep disorders.

Are serum vitamin D, calcium and phosphorous associated with restless leg syndrome? A systematic review and meta-analysis

BACKGROUND

It is hypothesized that vitamin D deficiency, and calcium/phosphate imbalance could be involved in the pathophysiology of restless leg syndrome (RLS). This systematic review and meta-analysis of observational studies were carried out to reach a firm conclusion regarding the possible association between vitamin D, calcium and phosphorous levels with RLS in end-stage renal disease (ESRD) patients, other comorbidities and healthy population.

METHODS

PubMed, Scopus, ISI Web of Science, and Cochrane's library were systematically searched up to June 2020. Quality assessment of the included observational studies was performed using Newcastle-Ottawa Quality Assessment Scale. Statistical analyses were done using STATA 11.2. A P-value <0.05 were considered statistically significant.

RESULTS

A total of 36 studies involving 9590 participants were included in this systematic review and meta-analysis. We found that serum vitamin D level is significantly lower (WMD -3.39 ng/mL; 95% CI, -5.96 to -0.81; P = 0.010; I² = 86.2%) and phosphorous (SMD 0.19; 95% CI, 0.04-0.34; P = 0.011; I² = 83.6%) is significantly higher in RLS individuals compared to the non-RLS individuals. However, the mean difference of serum calcium was not significant in comparison between RLS and control groups (SMD -0.01; 95% CI, -0.19 to 0.18; P = 0.957; I² = 89.2%).

CONCLUSION

Results revealed a significant association between serum vitamin D and phosphorous with RLS. However, further prospective cohort studies and clinical trials are needed for better understanding of the relationship between these variables.

Sleep-Wake Disorders in Childhood

PURPOSE OF REVIEW

The presentation of sleep issues in childhood differs from the presentation in adulthood and may be more subtle. Sleep issues may affect children differently than adults, and distinct treatment approaches are often used in children.

RECENT FINDINGS

Sodium oxybate was approved by the US Food and Drug Administration (FDA) in October 2018 for an expanded indication of treatment of sleepiness or cataplexy in patients with narcolepsy type 1 or narcolepsy type 2 aged 7 years or older, with side effect and safety profiles similar to those seen in adults. Restless sleep disorder is a recently proposed entity in which restless sleep, daytime sleepiness, and often iron deficiency are observed, but children do not meet the criteria for restless legs syndrome or periodic limb movement disorder.

SUMMARY

Children's sleep is discussed in this article, including normal sleep patterns and effects of insufficient sleep. Sleep disorders of childhood are reviewed, including insomnia, obstructive sleep apnea, restless legs syndrome, parasomnias, narcolepsy, and Kleine-Levin syndrome. Children with neurologic issues or neurodevelopmental disorders frequently have sleep disorders arising from an interaction of heterogeneous factors. Further attention to sleep may often be warranted through a polysomnogram or referral to a pediatric sleep specialist. Sleep disorders may cause indelible effects on children's cognitive functioning, general health, and well-being, and awareness of sleep disorders is imperative for neurologists who treat children.

Sleeping without Prescription: Management of Sleep Disorders in Children with Autism with Non-Pharmacological Interventions and Over-the-Counter Treatments

Autism Spectrum Disorders (ASD) are lifelong neurodevelopmental conditions characterized by abnormal social interaction, communication, and behavior. Sleep disturbances represent a common comorbidity in children and adolescents with ASD, with prevalence ranging from 50 to 80%. It has been proved that sleep disruption worsens the symptoms of autism and results in challenging behaviors. Improving sleep should therefore be a primary therapeutic goal. Treatment options range from lifestyle modifications to pharmacological therapy. Several reviews have been written on pharmacological treatments, but very few on the beneficial effects of non-pharmacological interventions, over-the-counter drugs, and nutritional supplements. This study consists of a narrative review of the literature, presenting the available evidence on the following treatments: sleep education, behavioral interventions, complementary and alternative medicine (special mattresses and blankets, massage, aromatherapy, yoga, physical activity), and commonly used over-the-counter medications and supplements (antihistamines, melatonin, tryptophan, carnosine, iron, vitamins, and herbal remedies). For some treatments—such as melatonin and behavioral interventions—effectiveness in ASD is well established in the literature, while other interventions appear of benefit in clinical practice, even if specific studies in children and adolescents with ASD are lacking. Conversely, other treatments only seem to show anecdotal evidence supporting their use.

The prevalence of insomnia and restless legs syndrome among Japanese outpatients with rheumatic disease: A cross-sectional study

The prevalence of symptomatic insomnia and the prevalence of restless legs syndrome (RLS) are known to be higher among patients with rheumatic diseases compared to the general population. The prevalences of insomnia and RLS reported in a questionnaire by Japanese patients with rheumatic diseases at an outpatient clinic were analyzed herein. The association between the patients' disease activity and their sleep quality was analyzed. Of 121 rheumatic disease patients, 70 were enrolled. The median (interquartile range) age at enrollment was 62.0 (47.8-68.0) years. There were 58 women (82.9%) and 12 men (17.1%), and 43 patients (61.4%) with rheumatoid arthritis (RA), nine (12.9%) with systemic lupus erythematosus (SLE), and 18 (25.7%) with other rheumatic diseases. Twenty patients (28.6%) had one or more moderate-to-severe insomnia symptoms, and 10 (14.3%) were diagnosed with RLS. Among the patients with RA, the swollen joint count based on a 28-joint assessment (SJC28) was significantly higher in the insomnia group (n = 13) compared to the non-insomnia group (n = 30) (p = 0.006). A classification and regression tree (CART) analysis showed that the cut-off points of ≥3 mg/day prednisolone (PSL) treatment and <16.54% as the transferrin saturation (TSAT) value would best predict RLS in rheumatic disease. Patients with rheumatic disease had a high prevalence of symptomatic insomnia and RLS. A higher dose of PSL and lower TSAT were associated with the occurrence of RLS.

Efficacy of vitamin D replacement therapy in restless legs syndrome: a randomized control trial

PURPOSE

Restless legs syndrome is a movement sleep disorder that may be linked to dopaminergic dysfunction and in which vitamin D may play a role. This 12-week randomized, placebo-controlled trial elucidated the efficacy of vitamin D supplements in decreasing restless legs syndrome symptom severity.

METHODS

Thirty-five subjects with restless legs syndrome, diagnosed using the International Restless Legs Syndrome Study Group criteria, were enrolled. The subjects were randomized to orally receive either vitamin D (50,000 IU caplets) or a placebo. All medications were administered weekly using a direct observation technique. Clinical assessments, including those for restless legs syndrome severity, were conducted at baseline and the end of the study using the International Restless Legs Syndrome Study Group rating scale. The serum vitamin D levels and bone profiles were measured at baseline and every 4 weeks. The primary endpoint was the change in the restless legs syndrome severity score from baseline to week 12. There were 17 and 18 patients in the vitamin D and placebo groups, respectively.

RESULTS

The groups did not differ with respect to age, sex, restless legs syndrome severity, or vitamin D levels. Participants in the vitamin D group showed no significant change in the mean restless legs syndrome severity score compared with the placebo group.

CONCLUSIONS

The results suggest that vitamin D supplementation does not improve restless legs syndrome symptoms.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov : NCT02256215 (available from: https://clinicaltrials.gov/ct2/show/NCT02256215 ).