Neuromyelitis optica spectrum disorders in Iran

Sex ratio and age of onset in AQP4 antibody-associated NMOSD: a review and meta-analysis

BACKGROUND

Aquaporin-4 (AQP4) antibody-associated neuromyelitis optica spectrum disorder (NMOSD) is an antibody-mediated inflammatory disease of the central nervous system. We have undertaken a systematic review and meta-analysis to ascertain the sex ratio and mean age of onset for AQP4 antibody associated NMOSD. We have also explored factors that impact on these demographic data.

METHODS

A systematic search of databases was conducted according to the PRISMA guidelines. Articles reporting sex distribution and age of onset for AQP4 antibody-associated NMSOD were reviewed. An initially inclusive approach involving exploration with regression meta-analysis was followed by an analysis of just AQP4 antibody positive cases.

RESULTS

A total of 528 articles were screened to yield 89 articles covering 19,415 individuals from 88 population samples. The female:male sex ratio was significantly influenced by the proportion of AQP4 antibody positive cases in the samples studied (p < 0.001). For AQP4 antibody-positive cases the overall estimate of the sex ratio was 8.89 (95% CI 7.78-10.15). For paediatric populations the estimate was 5.68 (95% CI 4.01-8.03) and for late-onset cases, it was 5.48 (95% CI 4.10-7.33). The mean age of onset was significantly associated with the mean life expectancy of the population sampled (p < 0.001). The mean age of onset for AQP4 antibody-positive cases in long-lived populations was 41.7 years versus 33.3 years in the remainder.

CONCLUSIONS

The female:male sex ratio and the mean age of onset of AQP4 antibody-associated NMOSD are significantly higher than MS. The sex ratio increases with the proportion of cases that are positive for AQP4 antibodies and the mean age of onset increases with population life expectancy.

Neuromyelitis optica spectrum disorders registry system in Iran: Validity of data sets

BACKGROUND

A targeted structure for recording, monitoring, and follow-up of patients with neuromyelitis optica spectrum disorders (NMOSD) is in demand. To obtain the correct and uniform standardized information registry system, it is necessary to use a data set that has good validity to help policy-makers systematically plan for improvements in the quality of care. The main goal of the present study was to develop a NMOSD data set for the national registry system in Iran (NMORI) and to evaluate the validity of the presented data set.

METHODS

The NMORI data set consisted of baseline characteristics, disease and exposure history, background and past medical history, diagnosis and treatment, clinical features, imaging, and para-clinical findings. The content validity was evaluated by 18 experts from Iran, Japan, and Denmark by scoring each of the questionnaire items in term of transparency, simplicity, and relevance. According to the points given, the content validity index (CVI) and content validity ratio (CVR) scores were calculated and compared with the critical limit.

RESULTS

The current study was designed as a 125-items data set which was considered valid. In terms of relevance 110 out of 125 items, simplicity 113 out of 125 items, and transparency 123 out of 125 items had Item-CVI>0.79. All Scale-level-CVI values were greater than 0.9, showing noticeable content validity. In this data set, 112 items had CVR > 0.49, which was considered an acceptable level of significance.

CONCLUSION

The implementing of NMORI is important in a developing country such as Iran with significant increasing prevalence of this disease. This registry facilitates a uniform and valid diagnosis and is considered valid for clinical investigation and epidemiological research on NMOSD. Scientists and healthcare policymakers can rely on a validated data set in order to have access to accurate data.

Research progress on pathogenesis and clinical treatment of neuromyelitis optica spectrum disorders (NMOSDs)

Neuromyelitis optica spectrum disorders (NMOSDs) are characteristically referred to as various central nervous system (CNS)-based inflammatory and astrocytopathic disorders, often manifested by the axonal damage and immune-mediated demyelination targeting optic nerves and the spinal cord. This review article presents a detailed view of the etiology, pathogenesis, and prescribed treatment options for NMOSD therapy. Initially, we present the epidemiology of NMOSDs, highlighting the geographical and ethnical differences in the incidence and prevalence rates of NMOSDs. Further, the etiology and pathogenesis of NMOSDs are emphasized, providing discussions relevant to various genetic, environmental, and immune-related factors. Finally, the applied treatment strategies for curing NMOSD are discussed, exploring the perspectives for developing emergent innovative treatment strategies.

Clinical and radiological profile of neuromyelitis optica spectrum disorders in a Pakistani cohort

BACKGROUND

The clinical and radiological characteristics of neuromyelitis optica spectrum disorder (NMOSD) from Pakistan is unknown. Our study aimed to describe the clinical and radiological features of NMOSD patients presenting to a Pakistani tertiary care center.

MATERIALS AND METHODS

This retrospective, observational study was conducted at the Neurology Department, Pakistan Institute of Medical Sciences between January 2017 and September 2021 (56 months). The study included patients diagnosed with neuromyelitis optica spectrum disorder (NMOSD) according to the 2015 International Panel for NMO Diagnosis (IPND) criteria, with the exclusion of patients under 12 years of age and those who tested positive for Myelin oligodendrocyte glycoprotein (MOG) IgG antibody. The patients were divided into two groups based on clinical presentation and the presence of NMO-IgG antibodies: NMO-IgG positive NMO (Seropositive NMO) and NMO-IgG negative (Seronegative NMO). The clinical features of NMOSD were recorded, and data was analyzed using SPSS version 26.0.

RESULTS

Among 204 patients with suspected demyelination, multiple sclerosis was diagnosed in 100 individuals (49.02%), while acute disseminated encephalomyelitis (ADEM), clinically isolated syndrome (CIS), and neuromyelitis optica (NMO) were found in 5 patients each (2.45%, 2.45%, and 17.65%, respectively). Out of 36 patients with NMO, 32 (88.89%) tested positive for NMO-Ab, while the remaining 4 (11.11%) were seronegative for both NMO and anti-MOG Abs. The mean age of NMO-positive patients who tested positive for NMO antibodies was 31.03±10.12 years, compared to 27.95±2.5 years for NMO-negative patients, though this difference was not statistically significant (p>0.05). Females were more commonly affected by NMO, accounting for 72.2% of the NMO-positive group, and there was a significant difference in clinical phenotypes between the two groups (p<0.05). The NMO-positive group predominantly had relapsing NMO presentation (75%), and 72.8% of these patients showed longitudinally extensive transverse myelitis on the MRI spine. Azathioprine was the most frequently administered treatment for positive NMO patients (69.44%), followed by rituximab and MMF. The follow-up period for the study participants lasted 24 months.

CONCLUSION

This is the first study on NMOSD cases in Pakistan. According to the present study, NMOSD is most prevalent among women in their forties. Relapsing NMO was the most common form of presentation. 89% of patients had antibodies against AQP4. 72.8% of patients suffered from LETM during the course of their disease. There are some features of our NMOSD cases that appear comparable with those around the world, despite some limitations in testing and access to care. It is clear that the clinical and radiological spectrums of patients with NMO and NMOSD in this cohort are similar. It is reasonable to suspect NMO if demyelinating episodes are not characteristic of MS.

Ongoing increase in incidence and prevalence of multiple sclerosis in south-eastern Iran: A three decade study

BACKGROUND

Prevalence of multiple sclerosis has been increased during the last decades throughout the world. Epidemiological studies could improve our understanding relating to its intrinsic and extrinsic causes.

OBJECTIVES

The current study has been conducted to determine the epidemiological features of MS in south-eastern Iran which is a semi-tropical area with different ethnicities.

METHODS

This longitudinal descriptive study was carried out in south-eastern Iran, based on information of MS patients registered at Zahedan University of Medical Sciences database from 1990 to 2020.

RESULTS

A total of 1045 cases were enrolled into the study. The age-standardized prevalence ratio of MS increased to 42.2/100,000 population by 2020. These figures showed increasing trends both in females and males and reached to 61.5 and 22.6 per 100,000 population, respectively by the year 2020. Likewise, the total incidence rate grew to its maximum amount of 4.5 in 2015. Female incidence also revealed an upward trend and peaked in 2016 to 6.4 while male incidence rate reached at its highest level of 1.8 in 2009.

CONCLUSION

MS prevalence ratios and incidence rates in south-eastern Iran have been increasing steadily, especially in women during the last three decades. The south-eastern part of Iran should be considered a high-risk region.

Worldwide prevalence of neuromyelitis optica spectrum disorder (NMOSD) and neuromyelitis optica (NMO): a systematic review and meta-analysis

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a progressive demyelinating disease of the central nervous system that has overlapping symptoms with multiple sclerosis (MS) but differs from it in a variety of ways. Previous studies have reported conflicting results trying to estimate the number of individuals affected by them which is why we designed this systematic review and meta-analysis to estimate the worldwide prevalence and incidence of NMOSD/NMO based on current evidence.

METHODS

We searched PubMed, Scopus, EMBASE, Web of Science, and gray literature including references from the identified studies, review studies, and conference abstracts which were published up to February 1, 2022. We used all MeSH terms pertaining to "NMOSD," "NMO," and all the terms on "prevalence," "incidence," and "epidemiology" to identify the search components. Pooled effect sizes were measured using random-effect model by DerSimonian-Laird.

RESULTS

The prevalence and incidence rates of NMOSD/NMO ranged from 0.07 to 10 and 0.029 to 0.880 per 100,000 population, respectively. The overall pooled prevalence of NMO per 100,000 population was 1.54 (I²: 98.4%, 95% CI: 1.13-1.96, P< 0.001) based on the 2006 criteria, 1.51 (I²: 99.4%, 95% CI: 1.21-1.81, P < 0.001) based on the 2015 criteria and 2.16 (I²: 89.4%, 95% CI: 1.46-2.86, P < 0.001) based on the 2006/2015 criteria. The overall annual incidence of NMO per 100,000 population was 0.155 (I²: 95%, 95% CI: 0.115-0.195, P < 0.001) based on the 2006 criteria and 0.278 (I²: 100%, 95% CI: 0.135-0.420, P < 0.001) based on the 2015 criteria. The prevalence rates were highest in French West Indies and South Korea, and lowest in Cuba and Australia, based on the 2006 and 2015 criteria, respectively. Also, the highest annual incidence rates were obtained for Sweden and Slovak republic and the lowest for Cuba and Australia based on the 2006 and 2015 criteria, respectively. All estimated rates were higher among females compared to males.

CONCLUSION

Although rare, NMOSD/NMO impact affected individuals in devastating ways. Several large-scale prospective studies are required to reach a comprehension of the epidemiological aspects of these notorious demyelinating conditions.

The prevalence, incidence, and clinical assessment of neuromyelitis optica spectrum disorder in patients with demyelinating diseases

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is characterised by recurrent attacks of optic neuritis and transverse myelitis. The purpose of this work was to identify the incidence and prevalence of NMOSD and its clinical characteristics in the population treated for demyelinating diseases in Western Mexico.

MATERIAL AND METHOD

A descriptive, retrospective study was carried out in the Department of Neurology, at the Sub-specialty Medical Unit, Specialties Hospital (known by its Spanish abbreviation UMAE-HE), of the National Western Medical Center (CMNO), Mexican Institute of Social Security (IMSS). A review of the electronic files for all patients with a diagnosis of NMOSD in 2019, was carried out in the State of Jalisco, Mexico.

RESULTS

Fifty-eight patients with NMOSD were included in the study. The incidence was 0.71/100 000 (CI 0.60-0.85) and the prevalence was 1.09/100 000 (CI 0.84-1.42). There were 79.3% women, and 20.6% were men (P = .01). All (100%) patients presented with anti-aquaporin-4 immunoglobulin G, and 89.6% showed seropositivity for anti-aquaporin-4 (CI 82.6-94.9). Magnetic resonance imaging was performed on 100% of patients, where 34.4% were normal, and 65.5% (38) abnormal, presenting with non-specific subcortical lesions (P = 0.04). The initial clinical presentation was optic neuritis (ON) in 58.6%; where 31.0% was bilateral ON, 20.7% was left ON, and 6.9% were right ON; transverse myelitis in 26.0%, area postrema syndrome (APS) in 10.3%, among others.

CONCLUSIONS

The incidence of NMOSD exceeds 0.71/100 000, the prevalence is low at 1.09/100 000, and NMOSD is predominantly found in women.

Incidence of neuromyelitis optica spectrum disorders in China: a large cohort study using claim data

OBJECTIVES

Population-based studies estimating the incidence of neuromyelitis optica spectrum disorders (NMOSDs) in Asia are limited, and the relationship between latitude and incidence has been scarcely investigated. We aimed to estimate the incidence of NMOSDs in Chinese adults and explore their relationship to latitude.

DESIGN

Cohort study based on data from the Urban Employee Basic Medical Insurance in China.

PARTICIPANTS

177 million people were followed from 2016 to 2017 in 20 provinces.

PRIMARY OUTCOME MEASURES

The incidence rate was estimated by Poisson distribution and reported as age-adjusted and sex-adjusted rates using the standard population.

RESULTS

There were 1313 incident NMOSD cases, with an overall incidence of 0.41 (95% CIs: 0.39 to 0.43) per 100 000 person-years. The incidence in females was higher, with a female-to-male IRR of 4.52. The incidence increased with age, peaking at 55-64 years in females and 65-74 years in males and then decreasing thereafter. The female-to-male IRRs were higher in those <55 years. The association between latitude and incidence was not statistically significant.

CONCLUSIONS

The incidence of NMOSD in Chinese adults was 0.41 per 100 000 person-years. There is no latitude gradient observed. Sex and age influence the risk of NMOSD, suggesting the role of genetic, hormonal and other related factors in the pathophysiology.

Increased Intracranial Pressure on a Patient with Neuromyelitis Optica Spectrum Disorder

Background:

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathic disease affecting central nervous system (CNS). CSF pressure in these patients is usually normal.

Case Presentation:

A 30-year-old woman was admitted with complaints of headache and lower limbs paresis. Lumbar puncture (LP) and magnetic resonance imaging were performed for the patient. Opening pressure was 42 cm H2O in the first LP. According to the clinical evidences, imaging, and the patient's positive aquaporin-4 antibody, the diagnosis of NMOSD was established.

Conclusion:

High intracranial pressure headache; however rare, may be the first sign of the onset of the acute exacerbation phase of NMOSD.

Physical, Emotional, Medical, and Socioeconomic Status of Patients With NMOSD: A Cross-Sectional Survey of 123 Cases From a Single Center in North China

Objective: This study aimed to assess the physical, emotional, medical, and socioeconomic conditions of patients with neuromyelitis optica spectrum disorder (NMOSD) in North China.

Methods: A cross-sectional survey of patients with NMOSD was performed, based on an established questionnaire from the Multiple Sclerosis Patient Survival Report 2018. Logistic regression analysis was conducted to define the significant determinants of certain physical or emotional characteristics of patients. A total of 123 patients were included.

Results: A total of 63.4% of participants were initially diagnosed with conditions other than NMOSD, with a median delay of 6 months for accurate diagnosis. An aggregate of 72.2% of patients had one or more relapses, corresponding to an annual relapse rate of 0.8. Paresthesia was the most frequent physical symptom among patients both at disease onset (53.7%) and throughout the duration of the disease (86.2%). Onset in elderly (>50 years) patients was associated with an annual Expanded Disability Status Scale increase ≥1, compared with onset in younger (<30 years) patients (P = 0.001, OR = 7.83). A total of 76.4% of patients had received attack-prevention treatments in the remission phase, and 31.7 and 10.6% of patients had ever been administered rituximab and traditional Chinese medicine, respectively. Additionally, 63.4 and 43.1% of patients reported participating in few or no social activities and being out of work because of the disease. To be noted, 76.4% of patients reported suffering from negative emotions, with the most frequent being worry (60.2%), with 20.3% of patients experiencing suicidal thoughts. The inability to work and participating in few or no social activities due to NMOSD were two determinants of experiencing negative emotions (P_work = 0.03, OR_work = 3.34; P_{socialactivities} = 0.02, OR_{socialactivities} = 3.19).

Conclusion: This study reported patient perspectives on NMOSD in North China, whereby demonstrating that the inability to work and participating in few or no social activities due to NMOSD rather than the physical impairment caused by the disease, was directly associated with patients experiencing negative emotions. This insight offers potential ways to manage patients' negative emotions by enhancing family and social support and facilitating active employment.

Neuromyelitis optica spectrum disorders: A nationwide Portuguese clinical epidemiological study

INTRODUCTION

Neuromyelitis optica spectrum disorder (NMOSD) is a rare disorder in which astrocyte damage and/or demyelination often cause severe neurological deficits.

OBJECTIVE

To identify Portuguese patients with NMOSD and assess their epidemiological/clinical characteristics.

METHODS

This was a nationwide multicenter study. Twenty-four Portuguese adult and 3 neuropediatric centers following NMOSD patients were included.

RESULTS

A total of 180 patients met the 2015 Wingerchuk NMOSD criteria, 77 were AQP4-antibody positive (Abs+), 67 MOG-Abs+, and 36 seronegative. Point prevalence on December 31, 2018 was 1.71/100,000 for NMOSD, 0.71/100,000 for AQP4-Abs+, 0.65/100,000 for MOG-Abs+, and 0.35/100,000 for seronegative NMOSD. A total of 44 new NMOSD cases were identified during the two-year study period (11 AQP4-Abs+, 27 MOG-Abs+, and 6 seronegative). The annual incidence rate in that period was 0.21/100,000 person-years for NMOSD, 0.05/100,000 for AQP4-Abs+, 0.13/100,000 for MOG-Abs+, and 0.03/100,000 for seronegative NMOSD. AQP4-Abs+ predominated in females and was associated with autoimmune disorders. Frequently presented with myelitis. Area postrema syndrome was exclusive of this subtype, and associated with higher morbidity/mortality than other forms of NMOSD. MOG-Ab+ more often presented with optic neuritis, required less immunosuppression, and had better outcome.

CONCLUSION

Epidemiological/clinical NMOSD profiles in the Portuguese population are similar to other European countries.

[Epidemiology of neuromyelitis optica spectrum disorder]

Neuromyelitis optica spectrum disorder (NMOSD) is a group of rare and mostly severe autoimmune demyelinating central nervous system disorders which prevalence is 0.7-1 per 100.000 population and incidence is 0.037-0.73 per 100.000 person-years. NMOSD may present as a combination of uni- or bilateral optic neuritis, transverse myelitis or lesions of brain stem and other brain regions. The symptoms are mostly relapsing (up to 97.5%) and progressive. Occurrence of relapses is associated with seropositivity for aquaporin-4 (up to 80% of NMOSD patients) and bears a less favorable prognosis (mortality up to 32%). Women seropositive for aquaporin 4 constitute 90% of NMOSD patients. Compared to other demyelinating disorders, NMOSD is characterized by late onset (mean age is about 39 years) and association with other autoimmune disorders, including systemic lupus erythematosus, myasthenia gravis and Sjogren's syndrome. A genetic predisposition was found among Blacks and Asians, with HLA-DRB1*03:01 gene associated with higher risk of NMOSD in Asians. The course of the disease tends to be more severe in Blacks. There are clusters of an increased incidence of NMOSD in the Carribeans and in the Far East. Continued increase of prevalence and incidence of NMOSD worldwide compels continued epidemiological research in order to provide early diagnosis and treatment for this disorder.

Comparisons of clinical phenotype, radiological and laboratory features, and therapy of neuromyelitis optica spectrum disorder by regions: update and challenges

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system (CNS) associated with autoantibody (ab) to aquaporin-4 (AQP4). There is obvious variation between regions and countries in the epidemiology, clinical features and management in NMOSD. Based on published population-based observation and cohort studies, the different clinical pattern of NMOSD has been seen in several geographical regions and some of these patients with NMOSD-like features do not fully meet the current diagnostic criteria, which is needed to consider the value of recently revised diagnostic criteria. At present, all treatments applied in NMOSD have made great progress, however, these treatments failed in AQP4 ab negative and refractory patients. Therefore, it is necessary to turn into an innovative idea and to open a new era of NMOSD treatment to develop novel and diverse targets and effective therapeutic drugs in NMOSD and to conduct the trails in large clinical samples and case-control studies to confirm their therapeutic effects on NMOSD in the future, which still remain a challenge.

Incidence and prevalence of neuromyelitis optica spectrum disorders in Slovakia

OBJECTIVE

: Neuromyelitis optica spectrum disorders (NMOSDs) are a group of rare, inflammatory, demyelinating diseases that affect the central nervous system. Neither the incidence nor the prevalence of NMOSD has been determined in Slovakia thus far. The aim of this study was to determine both the incidence and the prevalence of NMOSD in Slovakia using the 2015 International Panel of NMOSD diagnosis (IPND) criteria.

METHODS

: We performed a population-based study in Slovakia to estimate both the incidence and the prevalence of NMOSD during the period from 1 January 2006 through 31 December 2019. NMOSD cases were reported from multiple sources and the diagnosis was subsequently verified using the IPND criteria by a joint commitee of three neurologists. The prevalence is reported as number of cases per 100,000 inhabitans and the incidence as number of new cases per 1,000,000 person-years. Age-adjusted rates to the WHO standard population 2005-2025 were also calculated.

RESULTS

: We identified 63 NMOSD cases. The crude point-prevalence rate was 1.37 (95% CI 1.03-1.71) per 100,000 inhabitants. The crude indidence rate was 0.88 (95% CI 0.65-1.12) per 1,000,000 person-years. The age-adjusted point-prevalence rate was 1.42 (95% CI 1.07-1.84) per 100,000 persons and the age-adjusted incidence rate was 0.96 (95% CI 0.72-1.25) per 1,000,000 person-years.

CONCLUSION

: The NMOSD epidemiological situation in Slovakia is comparable to those reported from other Caucasian populations.

The possible role of Interleukin-6 as a regulator of insulin sensitivity in patients with neuromyelitis optica spectrum disorder

Background

Neuromyelitis optica spectrum disorder (NMOSD) is associated with inflammatory mediators that may also trigger downstream signaling pathways leading to reduce insulin sensitivity.

Methods

We aimed to determine the risk association of hyperinsulinemia in NMOSD patients with seropositive AQP4-IgG and the serum levels of interleukin (IL)-6 and IL-17A compared with the control group.

Serum levels of metabolic (Insulin, Fasting Blood Sugar (FBS), lipid profile) and inflammatory (IL-6 and IL-17) markers were assessed in 56 NMOSD patients and 100 controls.

Results

Hyperinsulinemia was more prevalent in NMOSD patients independent of age, sex and body mass index (BMI) (48.2% vs. 26%, p = 0.005) compared to control group. After adjusting age, sex and BMI, there was significant association between lower insulin sensitivity (IS) and NMOSD risk (95% CI: Beta = 0.73, 0.62 to 0.86, p = 0.0001).

Circulating levels of IL-6 and IL-17 were higher in NMOSD patients, and only IL-6 had an effect modifier for the association between lower insulin sensitivity and NMOSD risk.

Conclusions

Our data suggests that inflammatory pathogenesis of NMOSD leads to hyperinsulinemia and increases the risk of insulin resistance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02198-5.

Prevalence of neuromyelitis optica spectrum disorder in Belo Horizonte, Southeast Brazil

BACKGROUND

Studies on the prevalence of neuromyelitis optica spectrum disorder (NMOSD) are still scarce. The aim of the current study was to determine the prevalence rate of NMOSD in Belo Horizonte, southeast Brazil, where the prevalence rate of multiple sclerosis (MS) has already been established.

METHODS

For this observational study, eligible patients had to meet the 2015 International Panel for Neuromyelitis Optica Diagnosis, be seen at the study center between January 2000 and February 2019 and live in Belo Horizonte. The prevalence rate of NMOSD was estimated based on the number of MS and NMOSD patients seen at same Center during the same period, and the previously established prevalence of MS in Belo Horizonte.

RESULTS

During the study period, there were 69 patients with NMOSD, 60 (87.0%) of whom were females, and 44 (63.8%) non-whites. The median age at disease onset was 36.7 (4-72) years, the mean EDSS score 4.78±2.36, and the mean ARR 0.57±0.43. Anti-aquaporin-4 immunoglobulin testing was available for 61 (88.4%) patients, of whom 41 (67.2%) had a positive result. During the same period, 280 MS patients were seen. Considering the local known prevalence rate of MS of 18.1/100,000 inhabitants, the estimated NMOSD prevalence rate in Belo Horizonte was 4.52/100,000 (95% CI 3.72-5.43) inhabitants.

CONCLUSION

The prevalence rate of NMOSD in Belo Horizonte is high as compared with those found in most of the studies reported to date.

Worldwide Incidence and Prevalence of Neuromyelitis Optica: A Systematic Review

Objective

Since the last epidemiologic review of neuromyelitis optica/neuromyelitis optica spectrum disorder (NMO/NMOSD), 22 additional studies have been conducted. We systematically review the worldwide prevalence, incidence, and basic demographic characteristics of NMOSD and provide a critical overview of studies.

Methods

PubMed, Ovid MEDLINE, and Embase using Medical Subject Headings and keyword search terms and reference lists of retrieved articles were searched from 1999 until August 2019. We collected data on the country; region; methods of case assessment and aquaporin-4 antibody (AQP4-Ab) test; study period; limitations; incidence (per 100,000 person-years); prevalence (per 100,000 persons); and age-, sex-, and ethnic group–specific incidence or prevalence.

Results

We identified 33 relevant articles. The results indicated the highest estimates of incidence and prevalence of NMOSD in Afro-Caribbean region (0.73/100 000 person-years [95% CI: 0.45–1.01] and 10/100 000 persons [95% CI: 6.8–13.2]). The lowest incidence and prevalence of NMOSD were found in Australia and New Zealand (0.037/100 000 person-years [95% CI: 0.036–0.038] and 0.7/100,000 persons [95% CI: 0.66–0.74]). There was prominent female predominance in adults and the AQP4-Ab–seropositive subpopulation. The incidence and prevalence peaked in middle-aged adults. African ethnicity had the highest incidence and prevalence of NMOSD, whereas White ethnicity had the lowest. No remarkable trend of incidence was described over time.

Conclusion

NMOSD is a rare disease worldwide. Variations in prevalence and incidence have been described among different geographic areas and ethnicities. These are only partially explained by different study methods and NMO/NMOSD definitions, highlighting the need for specifically designed epidemiologic studies to identify genetic effects and etiologic factors.

Frequency of comorbidities in Neuromyelitis Optica spectrum disorder

BACKGROUND

Comorbidity may influence clinical aspects of neuromyelitis optica spectrum disorder (NMOSD). We estimated the prevalence of comorbidities to assess their association with outcomes.

METHODS

This retrospective study assessed records of NMOSD patients from 2008 to 2019, categorizing comorbidities into three groups: somatic, psychiatric and autoimmune. Severity of disease was evaluated by the Expanded Disability Status Scale, progression index (PI) and annualized relapse rate. The frequency of comorbidities was compared between anti-aquaporin 4 antibody (AQP4-IgG) seropositive and seronegative patients.

RESULTS

A total of 67 NMOSD patients were enrolled. Thirty-five (52.2%) patients reported at least one comorbidity. In total, 44 comorbidities were found, of which 24 occurred prior to NMOSD onset: 29 somatic, 13 psychiatric and 2 autoimmune entities. The most common comorbidities were anxiety disorders 7/67 (10.4%), followed by migraine 6/67 (8.9%) major depression disorder 6/67 (8.9%), iron deficiency anemia 8/54 (14.8%), and non-autoimmune hypothyroidism 4/67 (6.0%). Psychiatric comorbidities associated with PI in unadjusted (OR=0.538, 95% CI=0.141, 0.935, P=0.009) and adjusted models (OR=0.386, 95% CI=0.022, 0.751, P=0.038). A significantly higher frequency of psychiatric comorbidities was observed in the AQP4-IgG positive patients (P=0.031).

CONCLUSION

Half of the patients had comorbidities, suggesting screening for comorbidity as part of NMOSD care. The psychiatric comorbidities had impact on clinical outcome.

Clinical and Radiological Characteristics of Neuromyelitis Optica Spectrum Disorder: The Experience from Saudi Arabia

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune astrocytopathy that affects several regions of the central nervous system (CNS) with a predilection for the optic nerves and spinal cord. Epidemiological studies of NMOSD are uncommon in the Middle East and up-to-date, there are no such data from Saudi Arabia. In this study, we aim to study the clinical pattern of NMOSD patients in Saudi Arabia.

METHODS

A retrospective multi-center observational study was conducted at King Abdulaziz Medical City in Jeddah and Riyadh, Saudi Arabia. The inclusion criteria consisted of all the patients with either neuromyelitis optica according to the 2006 criteria or NMOSD according to the 2015 criteria. The study period was 20 years.

RESULTS

A total of 23 patients were included in the study. Four were males (17.4%) and 19 were females (82.6%). The attack type was optic neuritis in 3 patients (13.0%), transverse myelitis in 15 patients (65.2%), and both in 5 patients (21.7%). All patients (100%) received pulse steroid therapy (intravenous methylprednisolone 1 g for 5 days) at the onset of the disease. Fifteen patients had plasma exchange therapy (65.2%). All patients received maintenance immunosuppressive treatment except 1 (4.3%).

CONCLUSION

NMOSD is a rare, broad-spectrum, polyphasic, rare disorder primarily affecting the optic pathway and the spinal cord either in isolation or simultaneously. Unfortunately, there are no adequate studies that assess NMOSD cohorts in Saudi Arabia despite the increased number of diagnosed cases. In addition, there is no registry for this disorder with only a few specialized centers dealing with its management. It is time to establish specialized demyelinating disease centers and build expertise in both common and rare diseases in this category.

Optical Coherence Tomography in Neuromyelitis Optica spectrum disorder and Multiple Sclerosis: A population-based study

BACKGROUND

The aim of this study was to identify and compare the characteristics of retinal nerve layers using spectral domain-optical coherence tomography (SD-OCT) in neuromyelitis optica spectrum disorder (NMOSD), relapsing-remitting multiple sclerosis (RRMS) and healthy controls (HCs).

METHODS

It is a cross-sectional population-based study in Isfahan, Iran. We enrolled 98 participants including 45 NMOSD patients (90 eyes), 35 RRMS patients (70 eyes) and 18 HCs (36 eyes). Evaluation criteria were thickness of different sectors in peripapillary retinal nerve fiber layer (pRNFL) and intra-retinal layers around the macula. History of previous optic neuritis (ON) was obtained through chart review and medical record.

RESULTS

Without considering ON, total macular, ganglion cell layer (GCL) and pRNFL were significantly thinner in both groups of patients compared to HCs. On macular examination, GCL and total macular thickness were significantly thinner than HCs in all NMOSD and RRMS eyes with and without history of ON. While there was no significant difference between MS-ON and MS without a history of ON in the macular measures, the reduction in total macular and GCL thickness was significantly greater in NMOSD-ON compared to NMOSD without a history of ON. Also in NMOSD-ON eyes, the RNFL, GCL, IPL and GCIPL layers were significantly thinner than that of MS-ON. On the other hand, the pRNFL study showed significant thinning of all quadrants in the RRMS and NMOSD groups relative to HCs. While the decrease of pRNFL thickness in the eyes of NMOSD-ON and MS with and without a previous history of ON was significantly greater than that of HCs, no difference was observed between NMOSD without ON and HCs. In addition, in NMOSD patients, pRNFL was significantly thinner in eyes with history of ON compared to non ON-eyes. Furthermore, in patients with a history of ON, reduction in all sectors of pRNFl (except in T) was significantly greater in NMOSD compared to MS patients.

CONCLUSION

Our findings showed that although macular and retinal damage occurred in both NMOSD and RRMS patients without significant differences, the severity of injury in eyes with history of ON was significantly higher in NMOSD compared to MS patients, that could be considered as a marker to distinguish them. In addition, our results confirmed the absence of subclinical optic nerve involvement in NMOSD unlike MS patients.

Update on neuromyelitis optica spectrum disorder

PURPOSE OF REVIEW

Neuromyelitis optica spectrum disorder is an autoimmune disease that causes optic neuritis and transverse myelitis. Attacks can cause severe neurological damage leading to blindness and paralysis. Understanding of the immunopathogenesis of this disease has led to major breakthroughs in diagnosis and treatment. In the past 18 months, three successful phase 3 clinical trials have been published using targeted approaches to preventing relapses.

RECENT FINDINGS

Updates in epidemiology, imaging, quality of life and treatment for acute relapse and prevention have been published in the past 18 months. Epidemiology studies are distinguishing patients based on their antigen specificity for aquaporin-4 and myelin oligodendrocyte glycoprotein, which are increasingly recognized as separate immunological conditions. Imaging by MRI and optical coherence tomography continue to be developed as tools to distinguish neuromyelitis optica spectrum disorders (NMOSD) from other diseases. This is especially relevant as the recent clinical trials showed differences in response between aquaporin-4 seropositive and seronegative patients. The three drugs that were tested for prevention of NMOSD relapses were eculizumab, inebilizumab, and satralizumab. All of the trials were worldwide, placebo-controlled, double-masked studies that demonstrated a clear benefit with each approach.

SUMMARY

Recent research in NMOSD has resulted in improved diagnosis and approved treatments.

Neuromyelitis optica

Neuromyelitis optica (NMO; also known as Devic syndrome) is a clinical syndrome characterized by attacks of acute optic neuritis and transverse myelitis. In most patients, NMO is caused by pathogenetic serum IgG autoantibodies to aquaporin 4 (AQP4), the most abundant water-channel protein in the central nervous system. In a subset of patients negative for AQP4-IgG, pathogenetic serum IgG antibodies to myelin oligodendrocyte glycoprotein, an antigen in the outer myelin sheath of central nervous system neurons, are present. Other causes of NMO (such as paraneoplastic disorders and neurosarcoidosis) are rare. NMO was previously associated with a poor prognosis; however, treatment with steroids and plasma exchange for acute attacks and with immunosuppressants (in particular, B cell-depleting agents) for attack prevention has greatly improved the long-term outcomes. Recently, a number of randomized controlled trials have been completed and the first drugs, all therapeutic monoclonal antibodies, have been approved for the treatment of AQP4-IgG-positive NMO and its formes frustes.

Posterior Fossa Progressive Multifocal Leukoencephalopathy Secondary to Rituximab

Progressive multifocal leukoencephalopathy (PML) is a rare fatal central nervous system disorder characterized by infection-induced demyelination of white matter due to the opportunistic reactivation of John Cunningham virus in an immunocompromised patient. PML is associated with many immune-mediated diseases, lymphoproliferative conditions, and immunosuppressive agents. In this case report, we present a 79-year-old female patient diagnosed with rheumatoid arthritis who developed posterior fossa PML while on rituximab. She presented with subacute cerebellar ataxia, dysarthria, and nystagmus, and her brain MRI showed right pontine and pontocerebellar lesion with diffusion restriction and heterogenous enhancement highly characteristic of PML. Though many cases of PML with rituximab were reported in the literature, our case describes a rare type of PML affecting the posterior fossa in an HIV-negative patient on rituximab.

Epidemiology of Neuromyelitis Optica Spectrum Disorder and Its Prevalence and Incidence Worldwide

Neuromyelitis optica spectrum disorder (NMOSD) is an uncommon inflammatory disease of the central nervous system, manifesting clinically as optic neuritis, myelitis, and certain brain and brainstem syndromes. Cases clinically diagnosed as NMOSD may include aquaporin 4 (AQP4)-antibody-seropositive autoimmune astrocytopathic disease, myelin oligodendrocyte glycoprotein (MOG)-antibody-seropositive inflammatory demyelinating disease, and double-seronegative disease. AQP4-antibody disease has a high female-to-male ratio (up to 9:1), and its mean age at onset of ~40 years is later than that seen in multiple sclerosis. For MOG-antibody disease, its gender ratio is closer to 1:1, and it is more common in children than in adults. Its clinical phenotypes differ but overlap with those of AQP4-antibody disease and include acute disseminated encephalomyelitis, brainstem and cerebral cortical encephalitis, as well as optic neuritis and myelitis. Double-seronegative disease requires further research and clarification. Population-based studies over the past two decades report the prevalence and incidence of NMOSD in different populations worldwide. One relevant finding is the varying prevalence observed in different racial groups. Consistently, the prevalence of NMOSD among Whites is ~1/100,000 population, with an annual incidence of <1/million population. Among East Asians, the prevalence is higher, at ~3.5/100,000 population, while the prevalence in Blacks may be up to 10/100,000 population. For MOG-antibody disease, hospital-based studies largely do not observe any significant racial preponderance so far. This disorder comprises a significant proportion of NMOSD cases that are AQP4-antibody-seronegative. A recent Dutch nationwide study reported the annual incidence of MOG-antibody disease as 1.6/million population (adult: 1.3/million, children: 3.1/million). Clinical and radiological differences between AQP4-antibody and MOG-antibody associated diseases have led to interest in the revisions of NMOSD definition and expanded stratification based on detection of a specific autoantibody biomarker. More population-based studies in different geographical regions and racial groups will be useful to further inform the prevalence and incidence of NMOSD and their antibody-specific subgroups. Accessibility to AQP4-antibody and MOG-antibody testing, which is limited in many centers, is a challenge to overcome. Environmental and genetic studies will be useful accompaniments to identify other potential pathogenetic factors and specific biomarkers in NMOSD.

Efficacy and safety of rituximab in patients with refractory neuromyelitis optica spectrum disorders: A prospective observation in Iranian cases

Background:

Rituximab has been used successfully in the recent years for treatment of neuromyelitis optica spectrum disorders (NMOSD). However, a uniform treatment protocol for maintenance therapy and the best interval for evaluation and retreatment have not been postulated. We evaluated the efficacy and safety of rituximab treatment as second line therapy, in Iranian patients with refractory NMOSD, based on annualized relapse rate (ARR) and expanded disability status scale (EDSS).

Methods:

In this prospective before-after study, a total of 18 patients were treated with a loading dose of rituximab (375 mg/m² weekly in 4 consecutive weeks). Flow cytometric determination of CD19⁺ B cell in peripheral blood sample was carried every 6 weeks and patients were re-treated based on B cell repopulation with a single dose of 375 mg/m². Wilcoxon signed rank test was used to evaluate the ARR and EDSS before and after treatment. A p-value of <0.05 was considered statistically significant.

Results:

Of the 18 patients, 10 (55.5%) were relapse-free during the period of follow up. The EDSS scores were reduced in nine (50%) patients and stable in the remaining nine (50%). The mean EDSS score before and after treatment were 4.1±0.4 and 3.7±0.3, respectively, which was statistically significant. There was also a statistically significant reduction in median ARR after treatment (1.48 (range 0.47-5) vs. 0 (range 0-2)). Rituximab administration did not have significant adverse effect in 94% of patients.

Conclusion:

Repeated treatment with Rituximab is an effective and well-tolerated treatment in refractory NMOSD.

The clinical profile of NMOSD in Australia and New Zealand

Neuromyelitis optica spectrum disorders (NMOSD) are an inflammation of the central nervous system associated with autoantibodies to aquaporin-4. We have undertaken a clinic-based survey of NMOSD in the Australia and New Zealand populations with the aim of characterising the clinical features and establishing the value of recently revised diagnostic criteria. Cases of possible NMOSD and age and sex-matched controls with multiple sclerosis (MS) were referred from centres across Australia and New Zealand. Cases were classified as NMOSD if they met the 2015 IPND criteria and remained as suspected NMOSD if they did not. Clinical and paraclinical data were compared across the three groups. NMOSD was confirmed in 75 cases and 89 had suspected NMOSD. There were 101 controls with MS. Age at onset, relapse rates and EDSS scores were significantly higher in NMOSD than in MS. Lesions and symptoms referable to the optic nerve were more common in NMOSD whereas brainstem, cerebellar and cerebral lesions were more common in MS. Longitudinally extensive spinal cord lesions were seen in 48/71 (68%) of cases with NMOSD. Elevations of CSF, white cell count and protein were more common in NMOSD. We have confirmed a clinical pattern of NMOSD that has been seen in several geographical regions. We have demonstrated the clinical utility of the current diagnostic criteria. Distinct patterns of disease are evident in NMOSD and MS, but there remains a large number of patients with NMOSD-like features who do not meet the current diagnostic criteria for NMOSD and remain a diagnostic challenge.

Neuromyelitis optica spectrum disorders in the Arabian Gulf: challenges and growing experience

Neuromyelitis optica spectrum disorders (NMOSD) have been studied in different ethnic groups, including Asians, African-Americans, and Caucasians. Demonstrating the clinical features among diverse communities is important to understand the variable disease phenotypes, which will lead to further classification and better clinical management. Testing for antibody against aquaporin-4 (AQP4), the most common target antigen in NMOSD, is not available in many countries and tests use different methods, with variable sensitivity. With negative antibody results, the diagnosis of NMOSD becomes challenging and may affect the outcomes of patients with NMOSD. There are no adequate studies that assess NMOSD cohorts in the Arabian Gulf region, despite the increasing number of diagnosed cases. It is worth assessing NMOSD cohorts in the Arabian Gulf population to study the natural history of disease and to establish an epidemiological background for future perspectives. Various challenges to implement such a mission are outlined, including disease rarity, overlapping presenting symptoms and signs, which posed the issue of mimickers in the differential diagnosis, lack of specialized clinics, absence of highly sensitive testing methods for diagnosis, and the indefinite agreement on the negative AQP4 NMOSD criteria. Collaborative efforts started to take a place among many experts in the region to establish a registry of NMOSD patients for better perception of the disease pattern.

Neuromyelitis optica spectrum disorders in Arabian Gulf (NMOAG); establishment and initial characterization of a patient registry

OBJECTIVE

To describe the clinical and radiological characteristics of neuromyelitis optica spectrum disorders (NMOSD) patients from the Arabian Gulf relative to anti-aquaporin 4 antibody serostatus.

METHODS

Retrospective multicentre study of hospital records of patients diagnosed with NMOSD based on 2015 International Panel on NMOSD Diagnosis (IPND) consensus criteria.

RESULTS

One hundred forty four patients were evaluated, 64.3% were anti-AQP4 antibody positive. Mean age at onset and disease duration were 31±12 and 7 ± 6 years respectively. Patients were predominantly female (4.7:1). Overall; relapsing course (80%) was more common than monophasic (20%). Optic neuritis was the most frequent presentation (48.6%), regardless of serostatus. The proportion of patients (54.3%) with visual acuity of ≤ 0.1 was higher in the seropositive group (p = 0.018). Primary presenting symptoms of transverse myelitis (TM) were observed in 29% of patients, and were the most significant correlate of hospitalization (p<0.001). Relative to anti-APQ4 serostatus, there were no significant differences in terms of age of onset, course, relapse rates or efficacy outcomes except for oligoclonal bands (OCB), which were more often present in seronegative patients (40% vs.22.5%; p = 0.054). Irrespective of serostatus, several disease modifying therapies were instituted including steroids or immunosuppressives, mostly, rituximab and azathioprine in the cohort irrespective of serostatus. The use of rituximab resulted in reduction in disease activity.

CONCLUSION

This is the first descriptive NMOSD cohort in the Arabian Gulf region. Seropositive patients were more prevalent with female predominance. Relapsing course was more common than monophasic. However, anti-AQP4 serostatus did not impact disease duration, relapse rate or therapeutic effectiveness. These findings offer new insights into natural history of NMOSD in patients of the Arabian Gulf and allow comparison with patient populations in different World regions.

Dietary total antioxidant capacity and neuromyelitis optica spectrum disorder susceptibility

Purpose

Neuromyelitis Optica Spectrum Disorder (NMOSD) is a rare disease with unknown risk factors. The role of oxidative stress and nutritional factors is imprecise in NMOSD development. Therefore, this paper aims to evaluate the effects of dietary total antioxidant capacity (TAC) on the odds of NMOSD.

Design/methodology/approach

Dietary TAC was determined in 70 definite NMOSD cases and 164 healthy controls in term of Ferric Reducing Antioxidant Power (FRAP) method. A validated 168-item semi-quantitative food frequency questionnaire (FFQ) was used for dietary assessment. Three multivariate regression models were applied to analyze the odds of NMOSD across the TAC quartiles.

Findings

A significant inverse association was found between dietary TAC and odds of being assigned to the NMOSD group in all three regression models. In the fully adjusted model ORs (95% CI) in the second, third and fourth quartiles of TAC vs the first quartile were as follows: 0.11 (0.04-0.29), 0.05 (0.01-0.16) and 0.01 (0.00-0.05), respectively. Odds of NMOSD also indicated a significant decreasing trend across the quartiles of dietary TAC (p-trend: <0.01). Total energy (p < 0.01) as well as consumption of vegetables (p < 0.01), whole grains (p < 0.01), tea and coffee (p < 0.01), legumes (p < 0.01) and poultry (p < 0.01) significantly increased through the TAC quartiles.

Originality/value

In the present study, a new hypothesis was proposed concerning the influence of dietary TAC on the odds of NMOSD. A diet rich in foods with high TAC can be effective in the modification of the NMOSD odds.

The association between dietary sugar intake and neuromyelitis optica spectrum disorder: A case-control study

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an uncommon autoimmune disease of the central nerves system (CNS) by inflammatory nature. The effects of high dietary sugar intake on inflammation and dysbiosis have been received more attention in recent years. The aim of the present study was to investigate the association between various types of dietary sugar intake and NMOSD odds and clinical features.

METHOD

The current case-control study was conducted among 70 patients with definite NMOSD diagnosis based on 2015 international consensus criteria and 164 hospital-based controls. Demographic and anthropometric information in all participants and disease characteristics just in case group were obtained. Dietary data during the past year of study attendance was collected by a validated 168-item food frequency questionnaire. Participants were stratified into 3 tertiles according to each type of sugar intake and the third tertile considered as reference in multivariate regression models. The correlation between dietary sugar and disease features were analyzed using Pearson correlation test.

RESULTS

The mean ± SD of total sugar intake increased from 80.73 ± 17.71 to 208.71 ± 57.93 g/day across tertiles of total sugar intake. In fully adjusted model, lower intake of sugar was associates with decreased odds of NMOSD in the first tertile vs third tertile by ORs of: 0.02(CI:0.00-0.08; p-for-trend:0.00), 0.02(CI:0.00-0.10; p-for-trend:0.00), 0.23(CI:0.08-0.61; p-for-trend:0.00), 0.19(CI:0.06-0.58; p-for-trend:0.00) and 0.16(CI:0.05-0.51; p-for-trend:0.00) for glucose, fructose, galactose, lactose and sucrose, respectively. The odds of NMOSD had a 1.72-fold (CI: 1.43-2.03; p-for-trend:0.00) significant raise per every 10 g increase for total sugar intake. There was no significant correlation between various types of dietary sugar intakes and relapse rate or patients' disability.

CONCLUSION

The present study proposes a possible direct association between high intake of various sugar types and odds of suffering from NMOSD. More investigations are needed to prove this results.

Clinical characteristics of 153 Brazilian patients with neuromyelitis optica spectrum disorder (NMOSD)

BACKGROUND

The 2015 criteria for diagnosing neuromyelitis optica spectrum disorder (NMOSD) have encouraged several groups across the world to report on their patients using these criteria. The disease typically manifests with severe relapses of optic neuritis, longitudinally extensive myelitis and/or brainstem syndromes, often leading to severe disability. Some patients are seropositive for antibodies against aquaporin-4 (AQP4), others are positive for anti-myelin oligodendrocyte glycoprotein (MOG), while a few are negative for both biomarkers. The disease is complex, and only now are specific therapeutic clinical trials being carried out. The present study adds to the literature through detailed clinical data from 153 medical records of Brazilian patients.

METHODS

Retrospective assessment of medical records from nine specialized units in Brazil.

RESULTS

NMOSD was more prevalent in females (4.1:1), who had significantly fewer relapses than males (p = 0.007) but presented similar levels of disability over time. African ancestry was associated with higher levels of disability throughout the disease course (p < 0.001), although the number of relapses was similar to that observed in white patients. Concomitant autoimmune diseases were relatively rare in this population (6.5%). Positivity for anti-AQP4 antibodies was identified in 62% of the patients tested, while 3% presented anti-MOG antibodies. Anti-AQP4 antibodies were not associated to worse disease course. The last medical record showed that six patients had died and 13 were wheelchair-bound. Seventy percent of the patients did not respond to first-line therapy (azathioprine and/or corticosteroids), and five patients continued to relapse even after four different courses of treatment.

CONCLUSION

The present study adds to the reports from other countries presenting original data on Brazilian patients diagnosed with NMOSD according to the 2015 criteria.

Nationwide prevalence and incidence study of neuromyelitis optica spectrum disorder in Denmark

Objectives

To estimate the nationwide population-based incidence, prevalence, and geographical distribution of neuromyelitis optica (NMO) spectrum disorder (NMOSD) in Denmark based on the 2015 International Panel for NMO Diagnosis (IPND) criteria.

Methods

We conducted a multicentre, historically prospective study. Data were sourced from the Danish National Patient Registry, the Danish Multiple Sclerosis Registry, departments of neurology, and laboratories providing aquaporin-4 antibody test. Cases were selected based on the 2006 Wingerchuk and the 2015 IPND criteria and were individually validated by an expert panel.

Results

We confirmed NMO in 30 cases (2006 criteria) and NMOSD in 56 cases (2015 IPND criteria) between 2007 and 2014. Defined by the 2006 criteria, the incidence of NMO was 0.029 per 100,000 person-years (95% confidence interval [CI] 0.014–0.051), and the prevalence (aged 16 years and older) was 0.566 per 100,000 (95% CI 0.370–0.830). Based on the 2015 IPND criteria, the incidence of NMOSD was 0.070 per 100,000 person-years (95% CI 0.046–0.102), and the prevalence (aged 16 years and older) was 1.09 per 100,000 (95% CI 0.808–1.440), without regional differences.

Conclusions

Our estimates of incidence and prevalence are similar to other Caucasian population–based studies using the 2015 IPND criteria. We found no geographical clustering in Denmark.

Environmental risk factors in neuromyelitis optica spectrum disorder: a case-control study

Neuromyelitis optica spectrum disorder (NMOSD) has unknown risk factors. The aim of this study was to identify the environmental risk factors for NMOSD. A case-control study was conducted in Tehran from 2015 to 2016 among 100 patients with NMOSD. Sex-matched healthy controls (n = 400) were selected through random digit dialing (RDD). Logistic regression was used to estimate unadjusted and adjusted ORs (odds ratio) at 95% confidence intervals (CI) via SPSS. Compared with the control population, in NMOSD patients, the adjusted OR for low dairy consumption per week was (OR = 18.09; 95% CI 6.91, 47.37), following low sea food intake (OR = 13.91; 95% CI 6.13, 31.57) and low fruit and vegetable consumption (OR = 6.23; 95% CI 3.07, 12.62). The lower heavy physical activity (OR: 16.11, 95% CI 7.03, 36.91) among patients had risen the risk of NMOSD. A past history of head trauma was considered a risk for NMOSD (OR: 8.39, 95% CI 4.97, 14.16). The association between NMOSD and intentional abortion only among females (OR: 7.42, 95% CI 2.81, 19.55) was detected. This study indicates significant associations between dietary habits, life style, history of head trauma and intentional abortion in female and the later diagnosis of NMOSD.