High prevalence of restless legs syndrome/Willis Ekbom Disease (RLS/WED) among people living at high altitude in the Indian Himalaya

Prevalence and predictors of restless legs syndrome among patients having stable chronic obstructive pulmonary disease

BACKGROUND

Patients having COPD share some factors, e.g., chronic hypoxemia, anemia of chronic disease and nicotine use, which are also the risk factors for RLS hence predispose them to experience RLS in higher then general population. There are limited studies with methodological constraints evaluating the prevalence and/or correlates of RLS among patients with COPD.

METHODS

Consecutive adult patients of either gender, having stable COPD as per GOLD guidelines 2021, were assessed for RLS using IRLSSG (2014) criteria (excluding RLS mimics) and the severity of RLS was determined in participants having RLS. Phenomenology of RLS, past medical history and laboratory parameters were gathered. Insomnia and depression were assessed using the insomnia severity index and PHQ-9, respectively.

RESULTS

Participants' (N = 210) mean age was 63.02 ± 8.19 years, and 83.8% of subjects were men. 12.9% of participants were found to have RLS. Among those having RLS, nearly half (51.9%) had moderate symptoms, and 18.5% experienced severe symptoms. RLS was more prevalent among younger, females, those having severe COPD, participants having exacerbation of COPD in the previous year, lower post-bronchodilator FEV1, higher dyspnea and COPD assessment test score. Multivariate analysis showed that younger age, female gender, lower post-bronchodilator FEV1, lower FEV1/FVC ratio and higher serum creatinine increased the odds of having RLS. Depressive symptoms were more frequent in participants having RLS.

CONCLUSIONS

The present study found that the prevalence of RLS among patients with stable COPD was higher than the general population. Female gender, younger age, higher airflow limitation and higher serum creatinine (though in the physiological range) increase the odds of having RLS. Stable patients with COPD having these characteristics must be screened for RLS.

Prevalence and clinical characteristics of sleep disorders in chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND

Sleep disorders, including obstructive sleep apnea (OSA), restless leg syndrome (RLS) and insomnia, are present in chronic obstructive pulmonary disease (COPD) with varied prevalence. The aim of this systematic review and meta-analysis was to investigate prevalence of OSA, RLS and insomnia in patients with COPD and summarize their clinical characteristics.

METHODS

We searched PubMed, Web of Science and Scopus for eligible articles reporting the prevalence of OSA, RLS, and insomnia in COPD patients. The Newcastle‒Ottawa scale was applied for quality assessment. Odds ratios or mean differences with 95 % confidence intervals (CIs) were applied for the overall prevalence calculation and clinical characteristics assessment. Sensitivity analysis, subgroup analysis and meta-regression were conducted to evaluate the heterogeneity of the results.

RESULTS

Sixty articles reporting the prevalence of sleep disorders in patients with COPD were included, and the prevalence of OSA, RLS, and insomnia reached 29.1 %(95%CI 27.2%-30.9 %), 21.6 %(95%CI 11.8%-33.3 %) and 29.5 %(95%CI 16.9%-44.0 %), respectively. COPD patients with OSA were characterized by male sex (OR 1.631 95 % CI: 1.231-2.161), obesity(kg/m2) (MD 4.435, 95 % CI 3.218-5.652), higher Epworth Sleepiness Scale (MD: 3.741, 95 % CI: 0.655-6.828, p = 0.018), better pulmonary function (MD 5.66, 95 % CI 3.546-7.774) and higher risks of hypertension (OR 1.933 95 % CI 1.382-2.70) and diabetes (OR 1.898 95 % CI 1.264-2.849). COPD patients with RLS were associated with a higher Epworth sleepiness scale (ESS) score (MD 3.444, 95 % CI 1.880-5.008) and a longer COPD duration(year) (MD: 3.656, 95 % CI: 2.209-5.103). COPD patients with insomnia were characterized by female sex(OR 0.556, 95%CI 0.545,0.567, p < 0.001).

CONCLUSION

Our study suggests that OSA, RLS and insomnia are common in COPD patients with specific clinical characteristics. Further studies are needed to explore the interactions between COPD and sleep disorders.

Restless legs syndrome: From clinic to personalized medicine

Restless legs syndrome (RLS) is a common neurological sensorimotor disorder that impairs sleep, mood and quality of life. RLS is defined by an urge to move the legs at rest that increases in the evening and at night, and is frequently associated with metabolic and cardiovascular diseases. Symptoms frequency, age at RLS onset, severity, familial history and consequences of RLS vary widely between patients. A genetic susceptibility, iron deficiency, dopamine deregulation, and possible hypo-adenosinergic state may play a role in the pathophysiology of RLS. Polysomnographic recordings found often periodic leg movements during sleep and wakefulness in patients with RLS. RLS can be classified as primary or comorbid with major diseases: iron deficiency, renal, neurological, rheumatological and lung diseases. First-line treatments are low-dose dopamine agonists, and alpha-2-delta ligands depending on the clinical context, and second/third line opiates for pharmacoresistant forms of RLS. Augmentation syndrome is a serious complication of dopamine agonists and should be prevented by using the recommended low dose. Despite an increase in knowledge, RLS is still underdiagnosed, poorly recognized, resulting in substantial individual health burden and socioeconomic coast, and education is urgently needed to increase awareness of this disabling disorder.

Modification and Validation of a Diagnostic Questionnaire for Restless Legs Syndrome: Modified-Restless Legs Syndrome Diagnostic Questionnaire (m-RLS-DQ)

Background

Diagnostic questionnaire that are available for restless legs syndrome does not include items related to RLS mimics and, hence, increases chances of false positive cases. This study aimed at modification and validation of RLS-diagnostic Questionnaire.

Methods

During modification, additional items were identified, developed, and subjected to evaluation by experts. Experts were requested to validate the content of each item. Based on their responses, content validity indices (average and universal agreement) were calculated. It was then translated to Hindi and validated in a clinical population that included patients with RLS, somatic symptoms disorder, anxiety, other RLS mimics, and osteoarthritis. In addition, a group of healthy controls was also included. Face, concurrent, and discriminant validities were calculated.

Results

Among 209 subjects, nearly 40 subjects had clinical diagnosis of RLS, osteoarthritis, somatic-symptoms-disorder, and anxiety disorder, each. In addition, 16 patients had other RLS mimics (akathisia, varicose veins, BFS, leg-cramps, chronic insomnia) and 30 were healthy controls. After multiple revisions, content validity indices achieved a score of 1 for m-RLS-DQ. Sensitivity and specificity of m-RLS-DQ v. 1.4 for the diagnosis of RLS were 94.9% and 94.1%, respectively. For the diagnosis of RLS, PPV was 78.7%, and NPV was 98.7% with an accuracy of 94.3%. Less than one fourth of participants having chronic insomnia, somatic symptoms disorder, anxiety disorder, and knee osteoarthritis were found to be false positive on m-RLS-DQ; however, none of the healthy controls were found positive on m-RLS-DQ. Concurrent validity with clinical diagnosis of RLS was 0.83 (P < 0.001). Discriminant validity with somatic symptoms disorder was -0.14 (P = 0.03) and with osteoarthritis -0.24 (P < 0.001).

Conclusion

m-RLS-DQ is a valid instrument with acceptable psychometric properties, which can be used for the screening as well as diagnosis of RLS in clinical practice and research studies.

A Randomized, Open Label, Exploratory Trial Comparing Efficacy of Amantadine and Ropinirole in Restless Legs Syndrome

Objective  Amantadine has both anti-glutamatergic and dopaminergic action and may improve restless legs syndrome (RLS). We compared the efficacy and adverse-effect profile of amantadine and ropinirole in RLS. Methods  In this randomized, open-label, 12-week flexible-dose exploratory study, RLS patients with international RLS study group severity scale score (IRLSS) > 10 were randomized to receive either amantadine(100-300mg/day) or ropinirole (0.5-2mg/day). Drug dose was increased until week-6 if IRLSS failed to improve by ≥10% of previous visit score. IRLSS change from baseline at week-12 was the primary outcome. Secondary outcomes included change in RLS-related quality of life (RLS-QOL) and insomnia severity index (ISI), along with clinical-global-impression of change/improvement (CGI-I), and proportion of patients with adverse-effects and resulting discontinuation. Results  Twenty-four patients received amantadine and 22 received ropinirole. Both groups had a significant effect for visit*treatment arm (F (2.19,68.15) =4.35;P = 0.01). With a similar baseline IRLSS, both intention-to-treat (ITT) and per-protocol analyses revealed comparable IRLSS until week-8, with ropinirole appearing superior from week-10 to week-12 (week-12 IRLSS, amantadine vs ropinirole:17.0  ±   5.7 vs 9.0  ±   4.4;P < 0.001). ITT analysis at week-12 showed comparable proportion of responders (≥10% IRLSS reduction) in both groups (P = 0.10). Both drugs improved sleep and QOL, but week-12 scores favoured ropinirole [(ISI:14.4  ±   5.7 vs 9.4  ±   4.5; P = 0.001) ;(RLS-QOL:70.4  ±   17.9 vs 86.5  ±   9.8; P = 0.005)]. CGI-I at week-12 favoured ropinirole (Mann-Whitney U = 35.50, S. E = 23.05;P = 0.01). Four patients in amantadine and two in ropinirole group developed adverse effects, with resulting discontinuation in two patients on amantadine. Conclusions  The present study reports equivalent reduction in RLS symptoms with both amantadine and ropinirole until week-8, with the latter being superior from week-10 onwards. Ropinirole was better tolerated.

Myoclonus and other jerky movement disorders

Myoclonus and other jerky movements form a large heterogeneous group of disorders. Clinical neurophysiology studies can have an important contribution to support diagnosis but also to gain insight in the pathophysiology of different kind of jerks. This review focuses on myoclonus, tics, startle disorders, restless legs syndrome, and periodic leg movements during sleep. Myoclonus is defined as brief, shock-like movements, and subtypes can be classified based the anatomical origin. Both the clinical phenotype and the neurophysiological tests support this classification: cortical, cortical-subcortical, subcortical/non-segmental, segmental, peripheral, and functional jerks. The most important techniques used are polymyography and the combination of electromyography-electroencephalography focused on jerk-locked back-averaging, cortico-muscular coherence, and the Bereitschaftspotential. Clinically, the differential diagnosis of myoclonus includes tics, and this diagnosis is mainly based on the history with premonitory urges and the ability to suppress the tic. Electrophysiological tests are mainly applied in a research setting and include the Bereitschaftspotential, local field potentials, transcranial magnetic stimulation, and pre-pulse inhibition. Jerks due to a startling stimulus form the group of startle syndromes. This group includes disorders with an exaggerated startle reflex, such as hyperekplexia and stiff person syndrome, but also neuropsychiatric and stimulus-induced disorders. For these disorders polymyography combined with a startling stimulus can be useful to determine the pattern of muscle activation and thus the diagnosis. Assessment of symptoms in restless legs syndrome and periodic leg movements during sleep can be performed with different validated scoring criteria with the help of electromyography.

Consensus guidelines on the construct validity of rodent models of restless legs syndrome

Our understanding of the causes and natural course of restless legs syndrome (RLS) is incomplete. The lack of objective diagnostic biomarkers remains a challenge for clinical research and for the development of valid animal models. As a task force of preclinical and clinical scientists, we have previously defined face validity parameters for rodent models of RLS. In this article, we establish new guidelines for the construct validity of RLS rodent models. To do so, we first determined and agreed on the risk, and triggering factors and pathophysiological mechanisms that influence RLS expressivity. We then selected 20 items considered to have sufficient support in the literature, which we grouped by sex and genetic factors, iron-related mechanisms, electrophysiological mechanisms, dopaminergic mechanisms, exposure to medications active in the central nervous system, and others. These factors and biological mechanisms were then translated into rodent bioequivalents deemed to be most appropriate for a rodent model of RLS. We also identified parameters by which to assess and quantify these bioequivalents. Investigating these factors, both individually and in combination, will help to identify their specific roles in the expression of rodent RLS-like phenotypes, which should provide significant translational implications for the diagnosis and treatment of RLS.

Restless legs syndrome: Over 50 years of European contribution

Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterised by an urge to move the limbs with a circadian pattern (occurring in the evening/at night), more prominent at rest, and relieved with movements. RLS is one of the most prevalent sleep disorders, occurring in 5%-10% of the European population. Thomas Willis first described RLS clinical cases already in the 17th century, and Karl-Axel Ekbom described the disease as a modern clinical entity in the 20th century. Despite variable severity, RLS can markedly affect sleep (partly through the presence of periodic leg movements) and quality of life, with a relevant socio-economic impact. Thus, its recognition and treatment are essential. However, screening methods present limitations and should be improved. Moreover, available RLS treatment options albeit providing sustained relief to many patients are limited in number. Additionally, the development of augmentation with dopamine agonists represents a major treatment problem. A better understanding of RLS pathomechanisms can bring to light novel treatment possibilities. With emerging new avenues of research in pharmacology, imaging, genetics, and animal models of RLS, this is an interesting and constantly growing field of research. This review will update the reader on the current state of RLS clinical practice and research, with a special focus on the contribution of European researchers.

Prevalence, risk factors and effects of restless legs syndrome in COPD patients

Restless legs syndrome (RLS), a sensory motor disorder, is commonly seen amongst chronic obstructive pulmonary disease (COPD) patients. We conducted a study to know its prevalence in COPD and analyse the possible cause and effect of RLS. It is an analytical cross-sectional study conducted between July 2016-December 2020.The prevalence of RLS was evaluated in patients of COPD using RLS diagnostic criteria. Spirometry, iron profile and arterial blood gas analysis was performed in all the patients to evaluate the cause of RLS. The effect was evaluated with diagnostic criteria for insomnia and patient health questionnaire (PHQ2) for depression. There were 205 participants with a mean age of 59±8 years, 182 (88.7%) men and 23 (11.2%) women. The mean body mass index (BMI) was 29±3.9 kg/m2. The prevalence of RLS was 31.2%. RLS was more common amongst women compared to men (60.8% vs 27.4%). RLS was more prevalent among hypoxemic (PaO2<60 mm Hg) and hypercapnic (PaCO2>45 mm Hg) patients (p<0.016; p<0.017). The ROC curve plotted between PaO2 and RLS occurrence showed that the patients having PaO2 less than 76 mm of Hg were more prone to develop RLS. RLS patients had a higher incidence of insomnia as compared to those without RLS (68.8% vs 36.8%, p<0.001). COPD with RLS patients had more depressive symptoms with a higher patient health questionnaire 2 (PHQ2) score (35.9% vs 14.2%, p<0.001) compared to non-RLS COPD patients. The multiple regression analysis also confirmed that RLS led to insomnia and depressive symptoms in COPD patients. To conclude, RLS is common in COPD patients. RLS leads to insomnia and depression, thus should be identified and treated.

SARS-CoV-2 infection is associated with increased odds of insomnia, RLS and dream enactment behavior

BACKGROUND

Literature suggests that the COVID-19 pandemic has resulted in poor sleep quality, especially among the infected population. However, literature regarding the effect of COVID-19 pandemic and SARS-CoV-2 infection on occurrence of insomnia, restless legs syndrome and dream enactment behavior is either scarce or unavailable.

METHODS

This study was planned to assess the effect of SARS-CoV-2 infection on the occurrence of insomnia, restless legs syndrome (RLS) and dream enactment behavior (DEB). For this cross-sectional study, a questionnaire comprising of items related to demographic details, past medical history, and information related to SARS-CoV-2 infection was distributed through social media. Insomnia was diagnosed using clinical criteria. RLS, DEB, sleep quality, depression and anxiety were assessed using a validated questionnaire. Information regarding the use of hypnotic medications was also gathered.

RESULTS

Of the 1596 respondents, 37.2% reported disturbed sleep while insomnia was reported by 22.6% respondents. 27.3% of respondents reported RLS and 17.4% suffered DEB. The odds of insomnia were greater among males (OR = 1.27; 95% CI: 1.03-1.58; P < 0.02) and among those who had SARS-CoV-2 infection (OR = 1.76; 95% CI = 1.42-2.19; P < 0.001). Similarly, SARS-CoV-2 infection was also associated with increased odds of RLS (OR = 2.48; 95% CI = 1.98-3.11; P < 0.001) and DEB (OR = 1.58; 95%CI = 1.21-2.06; P < 0.001). Insomnia, RLS and DEB were more frequent among respondents who required oxygen therapy, those who experienced loss of taste and/or smell, depression and anxiety. Prevalence of insomnia, DEB and RLS was higher than said prevalence among respondents with no history of SARS-CoV-2 infection, but lower than that of those with positive history of SARS-CoV-2 infection. 5.3% of respondents reported taking hypnotic medications before infection, 7% during infection and 5.3% after infection.

CONCLUSION

SARS-CoV-2-infection-related factors in association with environmental factors have increased the prevalence of insomnia, DEB and RLS among subjects having infection. SARS-CoV-2-associated immunological changes, hypoxia and neurotropism may play a role in occurrence of insomnia, DEB and RLS.

Hypoxia and hemorheological properties in older individuals

Hypoxia is caused by insufficient oxygen availability for the organism leading to reduced oxygen delivery to tissues and cells. It has been regarded as a severe threat to human health and it is indeed implicated in pathophysiological mechanisms involved in the development and progression of many diseases. Nevertheless, the potential of controlled hypoxia interventions (i.e. hypoxia conditioning) for improving cardio-vascular health is gaining increased attention. However, blood rheology is often a forgotten factor for vascular health while aging and hypoxia exposure are both suspected to alter hemorheological properties. These changes in blood rheology may influence the benefits-risks balance of hypoxia exposure in older individuals. The benefits of hypoxia exposure for vascular health are mainly reported for healthy populations and the combined impact of aging and hypoxia on blood rheology could therefore be deleterious in older individuals. This review discusses evidence of hypoxia-related and aging-related changes in blood viscosity and its determinants. It draws upon an extensive literature search on the effects of hypoxia/altitude and aging on blood rheology. Aging increases blood viscosity mainly through a rise in plasma viscosity, red blood cell (RBC) aggregation and a decrease in RBC deformability. Hypoxia also causes an increase in RBC aggregation and plasma viscosity. In addition, hypoxia exposure may increase hematocrit and modulate RBC deformability, depending on the hypoxic dose, i.e, beneficial effect of intermittent hypoxia with moderate dose vs deleterious effect of chronic continuous or intermittent hypoxia or if the hypoxic dose is too high. Special attention is directed toward the risks vs. benefits of hemorheological changes during hypoxia exposure in older individuals, and its clinical relevance for vascular disorders.

Restless legs syndrome

Restless legs syndrome (RLS) is a common sensorimotor disorder characterized by an urge to move that appears during rest or is exacerbated by rest, that occurs in the evening or night and that disappears during movement or is improved by movement. Symptoms vary considerably in age at onset, frequency and severity, with severe forms affecting sleep, quality of life and mood. Patients with RLS often display periodic leg movements during sleep or resting wakefulness. RLS is considered to be a complex condition in which predisposing genetic factors, environmental factors and comorbidities contribute to the expression of the disorder. RLS occurs alone or with comorbidities, for example, iron deficiency and kidney disease, but also with cardiovascular diseases, diabetes mellitus and neurological, rheumatological and respiratory disorders. The pathophysiology is still unclear, with the involvement of brain iron deficiency, dysfunction in the dopaminergic and nociceptive systems and altered adenosine and glutamatergic pathways as hypotheses being investigated. RLS is poorly recognized by physicians and it is accordingly often incorrectly diagnosed and managed. Treatment guidelines recommend initiation of therapy with low doses of dopamine agonists or α₂δ ligands in severe forms. Although dopaminergic treatment is initially highly effective, its long-term use can result in a serious worsening of symptoms known as augmentation. Other treatments include opioids and iron preparations.

Status of the practice of sleep medicine in India during the COVID-19 pandemic

STUDY OBJECTIVES

Like other medical branches, the practice of sleep medicine has been affected by the COVID-19 pandemic; however, the actual impact is not known. This study was planned to assess the status of the practice of sleep medicine in India during the COVID-19 pandemic and lockdown.

METHODS

This was an online questionnaire-based descriptive study. A 25-item questionnaire was developed to assess the functioning of sleep laboratories, use of telemedicine, and positive airway pressure therapy during the COVID-19 pandemic in India. The questionnaire was sent to the sleep physicians of 2 major sleep medicine societies of India. Responses were analyzed.

RESULTS

In this study, the response rate was 64.6%. During this pandemic, 72% of physicians reported that they had closed sleep laboratory, whereas 24% reported shifting to home sleep apnea testing. Only half of the sleep physicians confirmed awareness of the disinfection guidelines proposed by the American Academy of Sleep Medicine to prevent COVID-19 infection in the sleep laboratory. However, almost all of them reported taking preventive measures like the use of protective gear. Sixty-one percent of physicians advised mitigating strategies as a temporary measure to their patients of obstructive sleep apnea. A total of 58.6% opined that auto-positive airway pressure might be used for uncomplicated obstructive sleep apnea without diagnostic polysomnography during the pandemic. Eighty-four percent of physicians reported that they were continuing their services through a telemedicine facility. Physicians reported that consultations for insomnia and circadian rhythm sleep disorders increased during the pandemic.

CONCLUSIONS

Sleep laboratories were reportedly closed during the COVID-19 pandemic, and most of the sleep physicians were providing services through telemedicine. The majority reported that auto-positive airway pressure without diagnostic polysomnography could be an effective option for uncomplicated obstructive sleep apnea. Consultation for insomnia and circadian rhythm sleep disorders reportedly increased during the lockdown.

Association between restless legs syndrome and peripheral neuropathy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

The coexistence of peripheral neuropathy (PN) and restless legs syndrome (RLS) or Willis-Ekbom disease is relatively frequent, but its prevalence has shown a high variability across studies. In addition, several reports have shown data suggesting the presence of PN in patients with idiopathic RLS.

METHODS

A search was undertaken using the PubMed, Embase and Web of Science Databases, from 1966 to 6 December 2020, crossing the search term 'restless legs syndrome' with 'neuropathy', 'polyneuropathy' (PNP) and 'peripheral neuropathy', and the references of interest for this topic were identified; a meta-analysis was performed, according to PRISMA guidelines, and a calculation of pooled prevalences, where appropriate, was made using standard methods.

RESULTS

Restless legs syndrome has been reported in 5.2%-53.7% of patients with PN (average 21.5%; 95% confidence interval 18.6%-24.5%), and PN has been reported in 0%-87.5% of patients with RLS (average 41.8%; 95% confidence interval 39.9%-43.6%), both being significantly more frequent than in controls. The heterogeneity across studies could be due to differences in the diagnostic criteria used for both RLS and PN. RLS is a frequent clinical complaint in patients with PN of different aetiologies, mainly diabetic PN, uraemic PNP, familial amyloid PNP, Charcot-Marie-Tooth disease and chronic dysimmune inflammatory PNP. Recent neurophysiological findings suggest the presence of small sensory fibre loss in patients diagnosed with idiopathic RLS, but it remains to be determined whether RLS associated with small sensory fibre loss and idiopathic RLS are different clinical entities.

CONCLUSIONS

Future studies including clinical and neurophysiological assessment and skin biopsy involving a large series of patients with PN and RLS are needed for a better understanding of the association between these two entities.

Restless legs syndrome among subjects having chronic liver disease: A systematic review and meta-analysis

Sleep disturbances are commonly reported in patients with chronic liver disease (CLD). Changes in quality of sleep in patients with CLD could be related to multiple factors viz., elevated levels of tryptophan, histamine, and increased turnover of dopamine in caudate-putamen and cingulate cortex. Also, iron metabolism disturbances are reported in patients with CLD. These changes may result in restless legs syndrome (RLS) that worsens sleep-quality. There have been reports suggesting an increased prevalence of RLS among patients with CLD. Literature was searched in PubMed, EMBASE, and Google Scholar. A total of twenty-two relevant articles were found. Out of these, nine studies have assessed the prevalence of RLS among patients with chronic liver disease or cirrhosis in the clinical population. Population prevalence reported from various studies was used to calculate odds ratio. Having included studies using various methods for diagnosis (clinical as well as questionnaires) pooled odds-ratio for the RLS was 8.62. It remains unaffected by study-method, gender, age, and geographical-area. However, studies using clinical diagnosis for RLS had lower odds compared to questionnaire based diagnosis. Studies varied with regards to diagnostic methods, age, gender, etiology, and severity of liver dysfunction. The severity and etiology of CLD and biochemical correlate of CLD were not found to be associated with RLS. Possible pathophysiological mechanisms are discussed for the occurrence of RLS in this population. In conclusion, the prevalence of RLS is higher among patients with CLD, however, the correlates are unknown.

Association between leg motor restlessness and depression among Chinese males living at high-altitude: the mediating role of insomnia

OBJECTIVE

Previous research has documented an association between insomnia and depression among patients with restless legs syndrome (RLS)/Willis-Ekbom disease. Given that leg motor restlessness (LMR) is closely related to RLS, the purpose of this study was to investigate the prevalence of insomnia and depression among individuals with LMR. In addition, we examined the associations among LMR, insomnia, and depression in a sample of young Chinese men living in high-altitude areas.

METHODS

Chinese military personnel working on the Qinghai Tibet Plateau (Lhasa, an altitude of 3600 m) were recruited in 2019 to complete a series of questionnaires. Participants having the urge to move their legs but not meeting the diagnostic criteria for RLS were classified as having LMR. Hierarchical linear regressions and mediational analyses using the SPSS PROCESS macro in SPSS were conducted to examine the associations among LMR, insomnia, and depression.

RESULTS

Of 196 participants, 36 (18%) had LMR. Only 1 participant was diagnosed with RLS. The proportions of participants suffering from insomnia who had LMR and did not have LMR were 44% and 22%, respectively. For depression, the proportions were 47% and 28%, respectively. Results of the hierarchical linear regressions showed that both LMR and depression were associated with increased insomnia symptoms. In addition, results from the mediational analyses indicated that the indirect effect of LMR on depression was significant and accounted for 52% of the total effect.

CONCLUSIONS

Participants with LMR had a higher prevalence of insomnia and depression compared with those without LMR. In addition, LMR was correlated with depression, and insomnia played a significant role in this co-occurrence.

Inflammatory bowel disease and restless leg syndrome

Objectives:

Inflammatory bowel disease (IBD) has been associated with restless leg syndrome (RLS). This study aims to explore the prevalence, clinical predictors, and severity of RLS in IBD patients compared to controls.

Methods:

We conducted a case-control study between January and December of 2019 comparing IBD patients with controls. Assessment of RLS was performed using the previously validated diagnostic restless leg syndrome questionnaire (RLSQ). Logistic regression analyses were applied to investigate associations between patient demographics and clinical features and RLS diagnosis.

Results:

A total of 218 IBD patients and 211 healthy controls were incorporated after excluding 6 patients with positional discomfort and 4 patients with habitual foot tapping. The mean age was 30.2±11.7 and 64% were females. The prevalence of RLS was 16/218 (7.34%) and 17/211 (8.06%) among cases and controls, respectively. Based on the RLSQ severity score, 6/16 (37.5%), 4/16 (25%) and 1/16 (6.3%) of the IBD patients with RLS had mild, moderate and severe RLS; respectively. The odds of IBD were lower among patients with confirmed RLS (OR=0.90, 95% CI=0.44-1.84, p = 0.78). In the logistic regression analysis, only vitamin B12 deficiency (OR=10.20, 95% CI=1.40-74.10, p = 0.022) was associated with RLS diagnosis among IBD patients.

Conclusion:

No difference was found in the prevalence of RLS between IBD patients and non-IBD controls. Vitamin B12 deficiency was associated with RLS diagnosis among patients with IBD.

Sleep and sleep disorders in pregnancy

Pregnancy is associated with a number of physiologic changes in the body including hormonal, anatomical, and mechanical. These changes alter many physiologic functions including sleep. The literature suggests that a number of women develop changes in duration, pattern, and quality of sleep during pregnancy. In addition, these changes also pave the way for expression of sleep disorders (e.g., insomnia, obstructive sleep apnea, and restless legs syndrome). Change in sleep and appearance of sleep disorders not only influence pregnant women, but also have negative influences on the fetus and outcomes of pregnancy. However, optimal management of these disorders may reverse adverse consequences. In this chapter, risk factors, clinical presentation, and management of insomnia, obstructive sleep apnea, and restless legs syndrome during pregnancy are discussed in view of the available literature.

Serum Interleukin-6 is Not Linked with Sleep-Quality, Restless Legs Syndrome, and Depression, But with 6-Month Survival in Hematological Malignancies

Background:

Serum interleukin (IL)-6 has been found to be associated with sleep quality, mood, and survival in patients with solid tumors. Results in these studies were confounded by knowledge of diagnosis to study subjects. Moreover, such data among subjects with hematological malignancies and data regarding restless legs syndrome is limited. The present study was, therefore, conducted to assess the sleep quality, depression, and restless leg syndrome in hematological malignancies and to study if there is any role of IL6 associated with it.

Methods:

Sixty-six subjects having hematological malignancy were included in this study after excluding the potential confounders. Sleep quality was examined using Pittsburg Sleep Quality Index, depression by the Patient Health Questionnaire-9. Diagnosis of RLS was made through clinical examination. Serum for measurement of IL-6 was collected at baseline and after 1 month of initiation of chemotherapy. Patients were followed up for 6 months.

Results:

Average age of study subjects was 50.16 years with male predominance. Nearly 22.7% had clinical depression, 28.8% had poor quality sleep, and restless legs syndrome (RLS) was reported in 6.1% cases. Nearly 22.7% patients died at 6 months. Disturbed sleep at baseline was associated with depression (odds ratio [OR] =7.89) and poor 6 months survival. Serum IL-6 did not show any association with sleep quality, restless-legs-syndrome, and depression. However, baseline high level of serum IL-6 (OR = 26.06) and low level after chemotherapy (OR = 0.03) were associated with poor survival at 6 months.

Conclusion:

Poor quality sleep, depression, and RLS are prevalent among adult subjects with hematological malignancies. Sleep disturbance, high pretreatment inflammatory and lowering of inflammatory load after chemotherapy increase likelihood for poor prognosis. Serum IL-6 did not show any association with sleep quality, restless legs syndrome and depression.

Sleep and Tibialis Anterior Muscle Activity in Mice With Mild Hypoxia and Iron Deficiency: Implications for the Restless Legs Syndrome

Restless legs syndrome (RLS) is a neurological disorder that entails an urge to move with a circadian pattern during the evening/night. RLS may be accompanied by decreased sleep time and increased occurrence of periodic leg movements during sleep (PLMS), which involve bursts of tibialis anterior (TA) muscle electromyogram (EMG). Mild hypoxia and non-anemic iron deficiency, a highly prevalent nutritional deficiency, are relatively unexplored factors in RLS pathophysiology. We tested whether mice exposed to mild hypoxia, alone or in combination with non-anemic iron deficiency, show decreased sleep time particularly in the light (rest) period and increased occurrence of TA EMG phasic events similar to human PLMS. Female C57BL/6J mice were fed diets with low or normal iron for 6 months from weaning and instrumented with electrodes to record the electroencephalogram and the EMG of both TA muscles. Mice were recorded in a whole-body plethysmograph while breathing a normoxic or mildly hypoxic (15% O₂) gas mixture for 48 h. Hypoxia increased minute ventilation during sleep. The low-iron diet decreased liver and serum iron, leaving blood hemoglobin and brainstem iron levels unaffected. Hypoxia, either alone or in combination with non-anemic iron deficiency, decreased non-rapid-eye-movement (non-REM) sleep time, but this occurred irrespective of the light/dark period and was not associated with increased occurrence of TA EMG events during non-REM sleep. These results do not support the hypothesis that mild hypoxia is sufficient to cause signs of RLS, either alone or in combination with non-anemic iron deficiency, pointing to the necessity of further susceptibility factors.

Comorbidities, treatment, and pathophysiology in restless legs syndrome

Restless legs syndrome, also known as Willis-Ekbom disease, is a common neurological condition whose manifestation is affected by complex environmental and genetic interactions. Restless legs syndrome can occur on its own, mostly at a young age, or with comorbidities such as cardiovascular disease, diabetes, and arterial hypertension, making it a difficult condition to properly diagnose. However, the concept of restless legs syndrome as being two entities, primary or secondary to another condition, has been challenged with genetic data providing further insight into the pathophysiology of the condition. Although dopaminergic treatment was formerly the first-line therapy, prolonged use can result in a serious worsening of symptoms known as augmentation. Clinical studies on pregabalin, gabapentin enacarbil, oxycodone-naloxone, and iron preparations have provided new treatment options, but most patients still report inadequate long-term management of symptoms. Studies of the hypoxic pathway activation and iron deficiency have provided valuable information about the pathophysiology of restless legs syndrome that should now be translated into new, more effective treatments for restless legs syndrome.

Comparison of Subjective Sleep Quality of Long-Term Residents at Low and High Altitudes: SARAHA Study

STUDY OBJECTIVES

To study the effect of altitude on subjective sleep quality in populations living at high and low altitudes after excluding cases of restless legs syndrome (RLS).

METHODS

This population-based study was conducted at three different altitudes (400 m, 1,900-2,000 m, and 3,200 m above sea level). All consenting subjects available from random stratified sampling in the Himalayan and sub-Himalayan regions of India were included in the study (ages 18 to 84 years). Sleep quality and RLS status were assessed using validated translations of Pittsburgh Sleep Quality Index (PSQI) and Cambridge Hopkins RLS diagnostic questionnaire. Recent medical records were screened to gather data for medical morbidities.

RESULTS

In the total sample of 1,689 participants included, 55.2% were women and average age of included subjects was 35.2 (± 10.9) years. In this sample, overall 18.4% reported poor quality of sleep (PSQI ≥ 5). Poor quality of sleep was reported more commonly at high altitude compared to low altitude (odds ratio [OR] = 2.65; 95% CI = 1.9-3.7; P < .001). It was more frequently reported among patients with RLS (29.7% versus 17.1% without RLS; P < .001). Other factors that were associated with poor quality of sleep were male sex, smoking, chronic obstructive pulmonary disease (COPD), and varicose veins. Binary logistic regression indicated that COPD (OR = 1.97; 95% CI = 1.36-2.86; P < .001), high altitude (OR = 2.22; 95% CI = 1.55-3.18; P < .001), and RLS (OR = 1.66; 95% CI = 1.12-2.46; P = .01) increased the odds for poor quality of sleep.

CONCLUSIONS

This study showed that poor quality of sleep was approximately twice as prevalent at high altitudes compared to low altitudes even after removing the potential confounders such as RLS and COPD.