Low vitamin D in narcolepsy with cataplexy

Severe Vitamin D Deficiency-A Possible Cause of Resistance to Treatment in Psychiatric Pathology

In the last few years, vitamin D functions have been studied progressively, and along with their main role in regulating calcium homeostasis, the potential function in the nervous system and the link between different psychiatric disorders and vitamin D deficiency have been revealed. The discovery of vitamin D receptors in multiple brain structures, like the hippocampus, led to the hypothesis that vitamin D deficiency could be responsible for treatment resistance in psychiatric diseases. The aim of this study was to analyze the current knowledge in the literature regarding vitamin D deficiency among individuals afflicted with psychiatric disorders and assess the potential therapeutic benefits of vitamin D supplementation. A systematic search was conducted on the PubMed database for articles published in the last five years (2016-2022) in English, focusing on human subjects. Results show that vitamin D deficiency has implications for numerous psychiatric disorders, affecting mood and behavior through its influence on neurotransmitter release, neurotrophic factors, and neuroprotection. It also plays a role in modulating inflammation, which is often elevated in psychiatric disorders. In conclusion, vitamin D deficiency is prevalent and has far-reaching implications for mental health. This review underscores the importance of exploring the therapeutic potential of vitamin D supplementation in individuals with psychiatric disorders and highlights the need for further research in this complex field.

Associations of serum 25-hydroxyvitamin D and subjective sleep measures in an Arctic population: Insights from the population-based Tromsø Study

Objective

To investigate the relation between serum 25-hydroxyvitamin D (s-25(OH)D) and subjective sleep measures in an Arctic population (69°N).

Methods

Cross-sectional data was collected from 21,083 individuals (aged ≥40 years) participating in the population based Tromsø Study: Tromsø7 (2015–2016). The present study included 20,438 participants, after having excluded respondents missing data on s-25(OH)D (n = 161) and/or subjective sleep measures (including sleep duration, insomnia, and daytime sleepiness)(n = 490). Based on s-25(OH)D (assessed using LC-MS/MS), participants were grouped as deficient (<30 nmol/L), insufficient (30–49.9 nmol/L), sufficient (50–75 nmol/L), or high (>75 nmol/L). Sleep duration was grouped as inadequate (ISD) if < 7 or ≥9 h. Linear and logistic regression were used to calculate unstandardized β-values and odds ratios [95% confidence intervals]. The analyses were adjusted for season, age, BMI, lifestyle factors and relevant comorbidities.

Results

In both men and women, s-25(OH)D was positively associated with sleep duration, and compared to the sufficient s-25(OH)D group, the insufficient s-25(OH)D group reported significantly shorter sleep duration in both sexes. There was an increased odds of ISD in both men and women but adjusted for confounding factors this was only significant in women (1.16 [1.03, 1.32], p = .017). In men, there were no significant associations between s-25(OH)D and the remaining sleep measures. Women in the high s-25(OH)D group had lower ESS-scores (−0.28 [-0.47, −0.08], p = .006), but higher odds of insomnia (1.16 [1.01, 1.33], p = .036) compared to women in the sufficient group.

Conclusions

In this Arctic population, a tenuous association was found between s-25(OH)D and subjective sleep measures, predominantly in women.

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25(OH)D was associated with self-reported sleep measures in this Arctic population.

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25(OH)D was positively associated with self-reported sleep duration in both sexes.

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Women with sufficient 25(OH)D had lower odds of insomnia.

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RCTs are needed to determine the role of vitamin D in sleep health.

Vitamin D and Sleep Regulation: Is there a Role for Vitamin D?

BACKGROUND

Vitamin D exerts multiple pleiotropic effects beyond its role in calcium-phosphate metabolism. Growing evidence suggests an association between hypovitaminosis D and sleep disorders, thus increasing the interest in the role of this vitamin in the regulatory mechanisms of the sleep-wake cycle.

OBJECTIVE

The study aimed to explore and summarize the current knowledge about the role of vitamin D in sleep regulation and the impact of vitamin D deficiency on sleep disorders.

METHODS

The main regulatory mechanisms of vitamin D on sleep are explained in this study. The literature was scanned to identify clinical trials and correlation studies showing an association between vitamin D deficiency and sleep disorders.

RESULTS

Vitamin D receptors and the enzymes that control their activation and degradation are expressed in several areas of the brain involved in sleep regulation. Vitamin D is also involved in the pathways of production of Melatonin, the hormone involved in the regulation of human circadian rhythms and sleep. Furthermore, vitamin D can affect sleep indirectly through non-specific pain disorders, correlated with alterations in sleep quality, such as restless legs syndrome and obstructive sleep apnea syndrome.

CONCLUSION

Vitamin D has both a direct and an indirect role in the regulation of sleep. Although vitamin D deficiency has been associated to sleep disorders, there is still scant evidence to concretely support the role of vitamin D supplementation in the prevention or treatment of sleep disturbances; indeed, more intervention studies are needed to better clarify these aspects.

The relationship between neuropsychological function and responsiveness to vitamin D supplementation using artificial neural networks

BACKGROUND

Vitamin D has recently attracted interest for its pleiotropic effects. Vitamin D supplements are a potentially important public health intervention, but the response to supplementation varies between individuals.

AIM

We aimed to assess the association between several neuropsychological parameters and the magnitude of response to vitamin D supplementation using an artificial neural network method.

METHODS

Neuropsychological function was assessed in 619 participants using standard questionnaires. The study participants received vitamin D capsules containing 50,000 IU vitamin D per week over 9 weeks. To assess the relationship between responsiveness to vitamin D supplements and the impact on these neuropsychological parameters, the best-performing artificial neural network algorithms were selected from a combination of different transfer functions in hidden and output layers and variable numbers of hidden layers (between two and 50). The performance of the artificial neural network algorithm was assessed by receiver operating characteristic analysis and variables of importance were identified.

RESULTS

The artificial neural network algorithm with sigmoid transfer function in both hidden and output layers could predict responsiveness to vitamin D supplementation effectively. The sensitivity and specificity were between 0.60 and 0.70 and 0.66 and 0.70, respectively. Cognitive abilities (42.5%), basal vitamin D (21.3%), body mass index (9.5%), and daytime sleepiness (8%) are the most widely used variables to predict changes in serum vitamin D levels.

CONCLUSIONS

Cognitive abilities status and baseline 25-hydroxyvitamin D are important novel modifiers of the enhancement in circulating 25-hydroxyvitamin D after vitamin D supplementation.

Prevalence and incidence of narcolepsy in a US health care claims database, 2008-2010

STUDY OBJECTIVES

To determine the prevalence and incidence of narcolepsy using a large US health care claims database.

METHODS

The Truven Health MarketScan Commercial Dissertation Database (THMCDD) was used to estimate prevalence and incidence of narcolepsy, with and without cataplexy, by age groups, gender, and region among patients under age 66 years with continuous enrollment for years 2008-2010. THMCDD contains health claims information for more than 18 million people. Prevalence was expressed as cases/100 000 persons. Average annual incidence (using varying criteria for latency between the diagnostic tests, polysomnograph coupled with multiple sleep latency test [MSLT], and the diagnosis) was expressed as new cases/100 000 persons/year.

RESULTS

There were 8 444 517 continuously enrolled patients and 6703 diagnosed with narcolepsy (prevalence overall: 79.4/100 000; without cataplexy: 65.4/100 000; with cataplexy: 14.0/100 000). On the basis of the three definitions of incidence, overall average annual incidence was 7.67, 7.13, and 4.87/100 000 persons/year. Incidence for narcolepsy without cataplexy was generally several times higher than narcolepsy with cataplexy. Prevalence and incidence were approximately 50% greater for females compared to males across most age groups. Prevalence was highest among the 21-30 years age group, with incidence highest among enrollees in their early 20s and late teens. Regionally, the North Central United States had the highest prevalence and incidence, whereas the West was the lowest.

CONCLUSION

We found greater prevalence and incidence of narcolepsy (including without cataplexy) than most previous studies. The increased proportions in females, enrollees in their early 20s, and US regional differences require further study. Increased awareness and early identification is critical in the management of this burdensome condition.

Risk of bone fractures in patients with narcolepsy: a nationwide population-based cohort study

OBJECTIVES

Narcolepsy symptoms, such as excessive daytime sleepiness or cataplexy, can pose a risk to safety. Stimulants or antidepressants have been used to treat these symptoms. The study investigated the risk of bone fractures in narcolepsy patients. Also, the exposure pattern of stimulants and antidepressants to the risk of bone fractures was examined.

METHODS

In all, 493 narcolepsy patients and 490 controls matched by gender, age, index year, and comorbidity severity were enrolled between 1998 and 2012, then followed until the end of 2013 using Taiwan's National Health Insurance Research Database. During the follow-up period, participants who developed bone fractures were identified. Cox regression analysis was used to calculate the hazard ratio (HR) with 95% confidence interval (CI) for the incidence rates of bone fractures between narcolepsy patients and unaffected controls.

RESULTS

Narcolepsy patients had a significantly increased risk of bone fractures compared with unaffected controls (19.6 versus 12.3 per 1000 person-years, HR: 1.74, 95% CI: 1.29-2.35). In addition, the use of stimulants in narcolepsy patients showed lower incidence rates of bone fractures compared to non-users (incidence rates were 14.2, 11.9, and 20.0 per 1000 person-years, respectively, among frequent users, infrequent users, and non-users), but the risk estimate was not statistically significant. The evidence for associations between antidepressant use in narcolepsy patients and bone fractures was contradictory.

CONCLUSION

This study highlights the need to pay attention to the risk of bone fractures in narcolepsy patients, and the importance of adequate stimulants use might reduce the risk of bone fractures.

Association of serum 25-hydroxyvitamin D concentrations with sleep phenotypes in a German community sample

Background

Sleep disorders and vitamin D deficiency are among the most common health problems. Few studies investigated the effect of vitamin D on objectively recorded sleep with sound methodological quality and reasonable temporal proximity.

Objective

To investigate the relationship between serum 25-hydroxyvitamin D (25(OH)D) concentrations and objective sleep parameters assessed within close temporal proximity in a population-based sample. It is expected that higher serum 25(OH)D concentrations are associated with 1) better objective sleep outcomes (longer sleep duration, higher sleep efficiency, earlier mid-sleep time) and 2) more positive subjective sleep evaluations.

Methods

A subset of participants (n = 1045) from the LIFE-Adult-Study was analysed. Measurement of serum 25(OH)D vitamin was performed using an electrochemiluminescence immunoassay. Actigraphic assessments were performed using SenseWear Pro 3 devices. The following objective sleep parameters were calculated: total sleep duration, night sleep duration, night sleep efficiency, midsleep time and wake after sleep onset (WASO). Subjective sleep evaluations were assessed via questionnaire (sleep quality (PSQI), daytime sleepiness (ESS)). Data were analysed applying a multiple linear regression model with a stepwise approach.

Results

The regression models revealed significant associations of serum 25(OH)D concentration with night sleep duration and midsleep time. No association was found for total sleep duration and night sleep efficiency. Higher serum 25(OH)D concentration was further associated with shorter WASO in males but longer WASO in females. Moreover, serum 25(OH)D concentration did not show any significant association with subjective sleep quality and daytime sleepiness.

Conclusion

The results indicate that a higher concentration of serum 25(OH)D is associated with longer and earlier night sleep. Although the present study was able to demonstrate an association between serum 25(OH)D concentration and objective sleep parameters, no conclusion about underlying mechanisms or causal inferences can be drawn.

The Association between Vitamin D Deficiency and Sleep Disorders: A Systematic Review and Meta-Analysis

Epidemiology studies have investigated the association between vitamin D and the risk of sleep disorders, but the results remain controversial. Therefore, we conducted this meta-analysis with the goal of clarifying the association between vitamin D and sleep disorders risk. All relevant studies were searched using PubMed, EMBASE, and Web of Science from inception to January 2018. Pooled odds ratios (ORs) and 95% confidence interval (CIs) were calculated using a fixed-effect model A total of nine studies (6 cross-sectional, 2 case-control, and 1 cohort studies) involving 9397 participants were included. By comparing the lowest verse highest levels of serum vitamin D, we found that participants with vitamin D deficiency (VDD) had a significantly increased risk of sleep disorders (OR: 1.50, 95% CI: 1.31, 1.72). Subgroup analysis showed that VDD also was associated with poor sleep quality (OR: 1.59, 95% CI: 1.23, 2.05), short sleep duration (OR: 1.74, 95% CI: 1.30, 2.32), and sleepiness (OR: 1.36, 95% CI: 1.12, 1.65). Subgroup analyses further indicated that serum 25(OH)D <20 ng/mL could significantly increase the risk of unhealthy sleep. This meta-analysis suggest that vitamin D deficiency is associated with a higher risk of sleep disorders. More high-quality cohort studies and randomized controlled trials (RCTs) are needed to verify this association.

The role of vitamin D in obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is a common disorder of multifactorial pathogenesis and is associated with obesity, diabetes and cardiovascular disease. Vitamin D is a fat-soluble vitamin with an important function in calcium absorption and homeostasis, which is also implicated in several nonskeletal conditions. The prevalence of vitamin D deficiency is increasing worldwide and is associated with similar metabolic disturbances to OSAS. Moreover, recent data suggest that in OSAS patients serum levels of vitamin D are lower compared with non-apnoeic subjects. However, the mechanisms linking vitamin D deficiency and OSAS are not completely understood and several hypotheses have been advanced. To date, a limited number of studies have assessed the association between lower serum concentrations of vitamin D and OSAS, and have reported inconsistent results. Similarly, contradictory results have been produced by studies which evaluated the effect of continuous positive airway pressure treatment on serum vitamin D levels. The aim of this review is to summarise current knowledge on the association between OSAS and vitamin D levels.

Due to multiple confounding factors, vitamin D deficiency is common among sleep apnoea patients; thus, screening should be performed when clinically indicatedhttp://ow.ly/L3ow30krmol

Narcolepsy Type 1 as an Autoimmune Disorder: Evidence, and Implications for Pharmacological Treatment

Narcolepsy type 1 (NT1) is a rare sleep disorder caused by the very specific loss of hypothalamic hypocretin (Hcrt)/orexin neurons. The exact underlying process leading to this destruction is yet unknown, but indirect evidence strongly supports an autoimmune origin. The association with immune-related genetic factors, in particular the strongest association ever reported in a disease with an allele of a human leukocyte antigen (HLA) gene, and with environmental factors (i.e., the H1N1 influenza infection and vaccination during the pandemic in 2009) are in favor of such a hypothesis. The loss of Hcrt neurons is irreversible, and NT1 is currently an incurable and disabling condition. Patients are managed with symptomatic medication, targeting the main symptoms (excessive daytime sleepiness, cataplexy, disturbed nocturnal sleep), and they require a lifelong treatment. Improved diagnostic tools, together with an increased understanding of the pathogenesis of NT1, may lead to new therapeutic and even preventive interventions. One future treatment could include Hcrt replacement, but this neuropeptide does not cross the blood-brain barrier. However, Hcrt receptor agonists may be promising candidates to treat NT1. Another option is immune-based therapies, administered at disease onset, with already some initiatives to slow down or stop the dysimmune process. Whether immune-based therapy could be beneficial in NT1 remains, however, to be proven.

The interfaces between vitamin D, sleep and pain

The role of vitamin D in osteomineral metabolism is well known. Several studies have suggested its action on different biological mechanisms, such as nociceptive sensitivity and sleep-wake cycle modulation. Sleep is an important biological process regulated by different regions of the central nervous system, mainly the hypothalamus, in combination with several neurotransmitters. Pain, which can be classified as nociceptive, neuropathic and psychological, is regulated by both the central and peripheral nervous systems. In the peripheral nervous system, the immune system participates in the inflammatory process that contributes to hyperalgesia. Sleep deprivation is an important condition related to hyperalgesia, and recently it has also been associated with vitamin D. Poor sleep efficiency and sleep disorders have been shown to have an important role in hyperalgesia, and be associated with different vitamin D values. Vitamin D has been inversely correlated with painful manifestations, such as fibromyalgia and rheumatic diseases. Studies have demonstrated a possible action of vitamin D in the regulatory mechanisms of both sleep and pain. The supplementation of vitamin D associated with good sleep hygiene may have a therapeutic role, not only in sleep disorders but also in the prevention and treatment of chronic pain conditions.

A population-based epidemiologic study of adult-onset narcolepsy incidence and associated risk factors, 2004-2013

An increase in narcolepsy incidence was noted after the novel pandemic influenza of 2009, leading to further interest in risk factors associated with this disease. However, there is limited data on the epidemiology of narcolepsy, particularly in the adult population. Therefore, we sought to examine narcolepsy incidence rates in the United States and describe associated characteristics. We performed a population based epidemiologic study of active duty military personnel. All outpatient clinics in the continental United States providing care for active duty military between 2004 through 2013 were included utilizing existing databases. Narcolepsy was defined in 3 ways: (1) 2 diagnoses of narcolepsy within 6months of each other, one made by a sleep expert; (2) 2 diagnoses by any provider followed by a narcolepsy prescription within 14days of last visit; and (3) procedure code for a sleep study followed by a narcolepsy diagnosis by a sleep expert within 6months. There were 1675 narcolepsy cases. Overall incidence of narcolepsy trended from 14.6 to 27.3 cases per 100,000 person-years, with an increase starting after 2005-2006 and peaking during the 2011-2012 influenza season. Higher frequencies were seen among females, non-Hispanic blacks, and members living in the south. Narcolepsy incidence rates among active duty military members are higher than previously described. The reason for the steady rise of incidence from 2005 to 2006 through 2011-2012 is unknown; however, these findings require further exploration. We detected risk factors associated with the development of narcolepsy which may aid in future study efforts.

Safety and persistence of the humoral and cellular immune responses induced by 2 doses of an AS03-adjuvanted A(H1N1)pdm09 pandemic influenza vaccine administered to infants, children and adolescents: Two open, uncontrolled studies

In children, 2 AS03-adjuvanted A(H1N1)pdm09 vaccine doses given 21 days apart were previously shown to induce a high humoral immune response and to have an acceptable safety profile up to 42 days following the first vaccination. Here, we analyzed the persistence data from 2 open-label studies, which assessed the safety, and humoral and cell-mediated immune responses induced by 2 doses of this vaccine. The first study was a phase II, randomized trial conducted in 104 children aged 6–35 months vaccinated with the A(H1N1)pdm09 vaccine containing 1.9 µg haemagglutinin antigen (HA) and AS03_B (5.93 mg tocopherol) and the second study, a phase III, non-randomized trial conducted in 210 children and adolescents aged 3–17 years vaccinated with the A(H1N1)pdm09 vaccine containing 3.75 µg HA and AS03_A (11.86 mg tocopherol). Approximately one year after the first dose, all children with available data were seropositive for haemagglutinin inhibition and neutralising antibody titres, but a decline in geometric mean antibody titres was noted. The vaccine induced a cell-mediated immune response in terms of antigen-specific CD4⁺ T-cells, which persisted up to one year post-vaccination. The vaccine did not raise any safety concern, though these trials were not designed to detect rare events. In conclusion, 2 doses of the AS03-adjuvanted A(H1N1)pdm09 vaccine at 2 different dosages had a clinically acceptable safety profile, and induced high and persistent humoral and cell-mediated immune responses in children aged 6–35 months and 3–17 years. These studies have been registered at www.clinicaltrials.gov NCT00971321 and NCT00964158.

Mean Platelet Volume, Vitamin D and C Reactive Protein Levels in Normal Weight Children with Primary Snoring and Obstructive Sleep Apnea Syndrome

Introduction

Studies on Mean Platelet Volume (MPV) in children with Sleep Disordered Breathing (SDB) report conflicting results and the hypothesis of an intermittent hypoxemia leading to a systemic inflammation is reaching consensus. Vitamin D exerts anti-inflammatory properties and its deficiency has been supposed to play a role in sleep disorders. Emerging interest is rising about Primary Snoring (PS) since it is reasonable that also undetectable alteration of hypoxia might predispose to an increased production of inflammatory mediators. In this perspective, in a group of children affected by SDB, our aim was to investigate MPV, vitamin D and C Reactive Protein (CRP) levels, which had been previously evaluated separately in different studies focused only on Obstructive Sleep Apnea Syndrome (OSAS).

Materials and Methods

We enrolled 137 children: 70 healthy controls (HC), 67 affected by SDB undergoing a polysomnographic evaluation, 22 with a diagnosis of PS and 45 with a diagnosis of OSAS. All patients underwent routine biochemical evaluations including blood cell counts, CRP and vitamin D.

Results

Children affected by SDB had a mean age of 8.49±2.19 and were prevalently males (23 females, 34%; 44 males, 66%). MPV levels were higher in OSAS and PS when compared to HC; platelet count (PLT) and CRP levels were higher while Vitamin D levels were lower in children with SDB when compared to HC. MPV levels were correlated with PLT (r = -0.54; p<0.001), vitamin D (r = -0.39; p<0.001) and CRP (r = 0.21; p<0.01). A multiple regression was run to predict MPV levels from vitamin D, CRP and PLT and these variables significantly predicted MPV (F = 17.42, p<0.0001; adjusted R2 = 0.37). Only platelet count and vitamin D added statistically significantly to the prediction (p<0.05).

Conclusion

The present study provides evidence of higher MPV and lower vitamin D levels in children with PS as well as in children with OSAS, and supports the underlying inflammation, hence, highlighting the importance of an early diagnosis of this previously considered benign form of SDB.

Low vitamin D levels in healthy controls and patients with autoimmune neuromuscular disorders in Greece

Normal autoimmune function is dependent on adequate levels of activated vitamin D, 25 hydroxy vitamin D [25(OH)D]. A recent study presented deficiency of 25(OH)D levels in Swedish MG patients. We aimed to study 25(OH)D levels in patients with MG and autoimmune polyneuropathies (PNP) at a southern latitude in Greece. Plasma levels of 25(OH)D were analyzed in Greek patients with MG (n = 19), immune-mediated PNP (N = 11) and in 30 Greek healthy age- and sex-matched controls. Ten MG patients received supplementation with vitamin D3. The MG Composite Score (MGC) and MG quality of life assessed disease severity in MG patients, whereas the INCAT Disability Scale assessed clinical features in the PNP patients. MG patients with and without vitamin D3 supplementation had higher 25(OH)D levels (mean 58.8 ± 16.3 and 62.0 ± 22.4 nmol/L, respectively) than PNP patients (mean 42.1 ± 11.5 nmol/L, p = 0.01) and healthy controls (mean 45.7 ± 13.8 nmol/L, p = 0.01). Plasma 25(OH)D levels was lower with age in all groups. There were no correlations between 25(OH)D and disease duration, MGC score, or INCAT score. Vitamin D deficiency was found in all Greek patient groups and healthy controls. Levels of 25(OH)D were higher in MG patients with as well as without vitamin D supplementation compared to healthy controls, whereas CIDP/GBS patients had levels similar to controls.

Immunogenicity and Safety of a Trivalent Inactivated Influenza Vaccine in Children 6 Months to 17 Years of Age, Previously Vaccinated with an AS03-Adjuvanted A(H1N1)Pdm09 Vaccine: Two Open-label, Randomized Trials

BACKGROUND

During the influenza pandemic 2009-2010, an AS03-adjuvanted A(H1N1)pdm09 vaccine was used extensively in children 6 months of age and older, and during the 2010-2011 influenza season, the A(H1N1)pdm09 strain was included in the seasonal trivalent inactivated influenza vaccine (TIV) without adjuvant. We evaluated the immunogenicity and safety of TIV in children previously vaccinated with the AS03-adjuvanted A(H1N1)pdm09 vaccine.

METHODS

Healthy children were randomized (1:1) to receive TIV or a control vaccine. Children were aged 6 months to 9 years (n = 154) and adolescents 10-17 years (n = 77) when they received AS03-adjuvanted A(H1N1)pdm09 vaccine at least 6 months before study enrolment. Hemagglutination inhibition (HI) and neutralizing antibody responses against the A(H1N1)pdm09 strain were evaluated before (day 0) and at day 28 and month 6 after study vaccination. Reactogenicity was assessed during the 7 day postvaccination period, and safety was assessed for 6 months.

RESULTS

At day 0, >93.9% of all children had HI titers ≥1:40 for the A(H1N1)pdm09 strain, which increased to 100% at both day 28 and month 6 in the TIV group. Between days 0 and 28, HI antibody geometric mean titers against A(H1N1)pdm09 increased by 9-fold and 4-fold in children 6 months to 9 years of age and 10-17 years of age, respectively.

CONCLUSION

AS03-adjuvanted A(H1N1)pdm09 vaccine-induced robust immune responses in children that persisted into the next season, yet were still boosted by TIV containing A(H1N1)pdm09. The reactogenicity and safety profile of TIV did not appear compromised by prior receipt of AS03-adjuvanted A(H1N1)pdm09 vaccine.

Impact of cytokine in type 1 narcolepsy: Role of pandemic H1N1 vaccination ?

Recent advances in the identification of susceptibility genes and environmental exposures (pandemic influenza 2009 vaccination) provide strong support that narcolepsy type 1 is an immune-mediated disease. Considering the limited knowledge regarding the immune mechanisms involved in narcolepsy whether related to flu vaccination or not and the recent progresses in cytokine measurement technology, we assessed 30 cytokines, chemokines and growth factors using the Luminex technology in either peripheral (serum) or central (CSF) compartments in a large population of 90 children and adult patients with narcolepsy type 1 in comparison to 58 non-hypocretin deficient hypersomniacs and 41 healthy controls. Furthermore, we compared their levels in patients with narcolepsy whether exposed to pandemic flu vaccine or not, and analyzed the effect of age, duration of disease and symptom severity. Comparison for sera biomarkers between narcolepsy (n = 84, 54 males, median age: 15.5 years old) and healthy controls (n = 41, 13 males, median age: 20 years old) revealed an increased stimulation of the immune system with high release of several pro- and anti-inflammatory serum cytokines and growth factors with interferon-γ, CCL11, epidermal growth factor, and interleukin-2 receptor being independently associated with narcolepsy. Increased levels of interferon-γ, CCL11, and interleukin-12 were found when close to narcolepsy onset. After several adjustments, only one CSF biomarker differed between narcolepsy (n = 44, 26 males, median age: 15 years old) and non-hypocretin deficient hypersomnias (n = 57, 24 males, median age: 36 years old) with higher CCL 3 levels found in narcolepsy. Comparison for sera biomarkers between patients with narcolepsy who developed the disease post-pandemic flu vaccination (n = 36) to those without vaccination (n = 48) revealed an increased stimulation of the immune system with high release of three cytokines, regulated upon activation normal T-cell expressed and secreted, CXCL10, and CXCL9, being independently and significantly increased in the group exposed to the vaccine. No significant differences were found between narcoleptics whether exposed to flu vaccination or not for CSF biomarkers except for a lower CXCL10 level found in the exposed group. To conclude, we highlighted the role of sera cytokine with pro-inflammatory properties and especially interferon-γ being independently associated with narcolepsy close to disease onset. The activity of the interferon-γ network was also increased in the context of narcolepsy after the pandemic flu vaccination being a potential key player in the immune mechanism that triggers narcolepsy and that coordinates the immune response necessary for resolving vaccination assaults.

Increased risk of narcolepsy in children and adults after pandemic H1N1 vaccination in France

An increased incidence of narcolepsy in children was detected in Scandinavian countries where pandemic H1N1 influenza ASO3-adjuvanted vaccine was used. A campaign of vaccination against pandemic H1N1 influenza was implemented in France using both ASO3-adjuvanted and non-adjuvanted vaccines. As part of a study considering all-type narcolepsy, we investigated the association between H1N1 vaccination and narcolepsy with cataplexy in children and adults compared with matched controls; and compared the phenotype of narcolepsy with cataplexy according to exposure to the H1N1 vaccination. Patients with narcolepsy-cataplexy were included from 14 expert centres in France. Date of diagnosis constituted the index date. Validation of cases was performed by independent experts using the Brighton collaboration criteria. Up to four controls were individually matched to cases according to age, gender and geographic location. A structured telephone interview was performed to collect information on medical history, past infections and vaccinations. Eighty-five cases with narcolepsy-cataplexy were included; 23 being further excluded regarding eligibility criteria. Of the 62 eligible cases, 59 (64% males, 57.6% children) could be matched with 135 control subjects. H1N1 vaccination was associated with narcolepsy-cataplexy with an odds ratio of 6.5 (2.1-19.9) in subjects aged<18 years, and 4.7 (1.6-13.9) in those aged 18 and over. Sensitivity analyses considering date of referral for diagnosis or the date of onset of symptoms as the index date gave similar results, as did analyses focusing only on exposure to ASO3-adjuvanted vaccine. Slight differences were found when comparing cases with narcolepsy-cataplexy exposed to H1N1 vaccination (n=32; mostly AS03-adjuvanted vaccine, n=28) to non-exposed cases (n=30), including shorter delay of diagnosis and a higher number of sleep onset rapid eye movement periods for exposed cases. No difference was found regarding history of infections. In this sub-analysis, H1N1 vaccination was strongly associated with an increased risk of narcolepsy-cataplexy in both children and adults in France. Even if, as in every observational study, the possibility that some biases participated in the association cannot be completely ruled out, the associations appeared robust to sensitivity analyses, and a specific analysis focusing on ASO3-adjuvanted vaccine found similar increase.

Obstructive sleep apnea syndrome and its association with vitamin D deficiency

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is a widespread disorder characterized by recurrent, partial or complete episodes of apnea due to upper airway tract obstruction during sleeping period. Deficiency of vitamin D has roles in development of many diseases. Association between presence and severity of OSAS and vitamin D has recently gained research interest.

AIM

The aim of our study was to investigate the association between serum 25-hydroxy [25 (OH)] vitamin D levels and severity of disease in patients with OSAS.

MATERIAL AND METHODS

One hundred and fifty OSAS patients (50 patients with mild, 50 with moderate, 50 with severe OSAS) who were diagnosed by polysomnography (PSG) and 32 non-OSAS controls who were referred to the Health Ministry Ankara Numune Training and Research Hospital, Endocrinology and Metabolism Department, from January 2010 to May 2011 were included in the study. Serum 25(OH)D, PTH, calcium and phosphorus levels were evaluated in all the patients who were recruited to the study.

RESULTS

There was no statistically significant difference in serum 25(OH)D levels between OSAS and controls (p>0.05). However, in subgroup analysis of OSAS, we found that the patients with severe OSAS had significantly lower levels of 25(OH)D as compared with other groups (p=0.003). Also, the number of patients with serum 25(OH)D deficiency (<10 μg/dl) were higher in OSAS group than in controls (p<0.05).

CONCLUSIONS

We found that when the severity of OSAS increases, 25(OH)D deficiency becomes more pronounced.

Vitamin D deficiency in patients with myasthenia gravis and improvement of fatigue after supplementation of vitamin D3: a pilot study

BACKGROUND

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder. Vitamin D has important roles both in the autoimmune response and in skeletal muscles. We determined the levels of 25-hydroxy vitamin D [25(OH)D] in patients with MG and in healthy subjects to determine whether vitamin D deficiency is present in MG and whether vitamin D supplementation has beneficial effects on fatigue.

METHODS

Plasma levels of 25(OH)D were analyzed in 33 patients with MG (22 males; mean age, 58 years) and in 50 healthy age- and sex-matched blood donors, without vitamin D3 medication. MG composite (MGC) score assessed fatigue. Thirteen patients with MG without previous vitamin D3 supplementation were started on vitamin D3 supplementation (cholecalciferol) 800 IU/day, with a follow-up examination after 2.5-10 months (mean, 6 months).

RESULTS

Patients with MG without pre-existing vitamin D3 supplementation (N = 16) had a mean MGC of 4.5 and lower plasma 25(OH)D levels (mean, 51 ± 19 nM) than healthy controls (69 ± 21 nM) (P = 0.017). Seventeen patients had pre-existing vitamin D3 supplementation, because of corticosteroid treatment, and their mean 25(OH)D was 79 ± 22 nM and mean MGC was 5.5. In the 13 patients who received cholecalciferol, 25(OH)D was overall increased at follow-up with 22% (P = 0.033) and MGC score improved by 38% (P = 0.05).

CONCLUSIONS

Plasma 25(OH)D levels are significantly lower in patients with MG compared with healthy controls. As vitamin D has beneficial effects on the autoimmune response and on fatigue score in patients with MG, we suggest monitoring this parameter in patients with MG and supplementation with vitamin D3 when 25(OH)D levels are low.