Disentangling Multiple Sclerosis heterogeneity in the French territory among genetic and environmental factors via Bayesian heritability analysis

BACKGROUND

This study aimed to investigate the factors contributing to the variability of Multiple Sclerosis (MS) among individuals born and residing in France. Geographical variation in MS prevalence was observed in France, but the role of genetic and environmental factors in explaining this heterogeneity has not been yet elucidated.

METHODS

We employed a heritability analysis on a cohort of 403 trios with an MS-affected proband in the French population. This sample was retrieved from REFGENSEP register of MS cases collected in 23 French hospital centers from 1992 to 2017. Our objective was to quantify the proportion of MS liability variability explained by genetic variability, sex, shared environment effects, region of birth and year of birth. We further considered gene x environment (GxE) interaction effects between genetic variability and region of birth. We have implemented a Bayesian liability threshold model to obtain posterior distributions for the parameters of interest adjusting for ascertainment bias.

RESULTS

Our analysis revealed that GxE interaction effects between genetic variability and region of birth represent the primary significant explanatory factor for MS liability variability in French individuals (29 % [95 %CI: 5 %; 53 %]), suggesting that additive genetic effects are modified by environmental factors associated to the region of birth. The individual contributions of genetic variability and region of birth explained, respectively, ≈15 % and ≈16 % of MS variability, highlighting a significantly higher MS liability in individuals born in the Northern regions compared to the Southern region. Overall, the joint contribution of genetic variability, region of birth, and their interaction was then estimated to explain 65 % [95 %CI: 35 %; 92 %] of MS liability variability. The remaining proportion of MS variability is attributed to environmental exposures associated with the year of birth, shared within the same household, and specific to individuals.

CONCLUSION

Overall, our analysis highlighted the interaction between genetic variability and environmental exposures linked to the region of birth as the main factor explaining MS variability within individuals born and residing in France. Among the environmental exposures prevalent in the Northern regions, and potentially interacting with genetic variability, lower vitamin D levels due to reduced sun exposure, higher obesity prevalence and higher pollution levels represent the main risk factors in influencing MS risk. These findings emphasize the importance of accounting for environmental factors linked to geographical location in the investigation of MS risk factors, as well as to further explore the influence of GxE interactions in modifying genetic risk.

Prevalence of multiple sclerosis in France in 2021: Data from the French health insurance database

BACKGROUND

France is among the countries with high prevalence of multiple sclerosis (MS). The most recent estimates are from 2012 and need to be updated because MS prevalence has increased worldwide.

OBJECTIVE

To estimate MS prevalence in France on December 31, 2021 and to describe the characteristics of the French MS population using data from the French national health insurance database (SNDS).

MATERIAL AND METHODS

Persons with MS (PwMS) were identified in the SNDS database (99% of national coverage) using an algorithm with three criteria: long-term disease status, hospitalizations, and MS-specific drug reimbursements. Crude and sex- and age-stratified prevalence rates were calculated with their 95% confidence intervals as well as the standardized prevalence stratified on the region of residence.

RESULTS

In total, 134,062 PwMS were identified (71.8% of women, median age 53.0±14.8years) yielding a prevalence of 197.6 per 100,000 (95% CI [196.5-198.7]). Prevalence rates in women and men were respectively 274.9 (95% CI [273.2-276.6]) and 115.2 (95% CI [114.0-116.4]). In metropolitan France, the highest prevalence rates were observed in the northeastern regions (e.g.>230 PwMS per 100,000 in Grand Est and Hauts-de-France), and the lowest rates in the southwestern regions (∼180 PwMS per 100,000 in Nouvelle-Aquitaine and Occitanie). Overall, 32.1% of PwMS had another long-term disease and 51.8% received at least one MS-specific drug in 2021.

CONCLUSION

MS prevalence in France has increased by ∼30% in the last 10years. This increase is probably linked to population ageing, longer survival of PwMS, and the long observation period. The part attributable to a possible increase in MS risk remains to be determined with incidence studies.

Performance of administrative databases for identifying individuals with multiple sclerosis

Administrative databases are an alternative to disease registries as a research tool to study multiple sclerosis. However, they are not initially designed to fulfill research purposes. Therefore, an evaluation of their performance is necessary. Our objective was to assess the performance of the French administrative database comprising hospital discharge records and national health insurance databases in identifying individuals with multiple sclerosis, in comparison with a registry that exhaustively compiles resident multiple sclerosis cases in Lorraine, northeastern France, as reference. We recorded all individuals residing in the Lorraine region who were identified by the administrative database or the registry as having multiple sclerosis from 2011 to 2016. We calculated the Matthews correlation coefficient and other concordance indicators. For identifying individuals with multiple sclerosis, the Matthews correlation coefficient by the administrative database was 0.79 (95% CI 0.78-0.80), reflecting moderate performance. The mean time to identification was 5.5 years earlier with the registry than the administrative database. Administrative databases, although useful to study multiple sclerosis, should be used with caution because results of studies based on them may be biased. Our study highlights the value of regional registries that allow for a more exhaustive and rapid identification of cases.

Autoreactive lymphocytes in multiple sclerosis: Pathogenesis and treatment target

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by destruction of the myelin sheath structure. The loss of myelin leads to damage of a neuron’s axon and cell body, which is identified as brain lesions on magnetic resonance image (MRI). The pathogenesis of MS remains largely unknown. However, immune mechanisms, especially those linked to the aberrant lymphocyte activity, are mainly responsible for neuronal damage. Th1 and Th17 populations of lymphocytes were primarily associated with MS pathogenesis. These lymphocytes are essential for differentiation of encephalitogenic CD8⁺ T cell and Th17 lymphocyte crossing the blood brain barrier and targeting myelin sheath in the CNS. B-lymphocytes could also contribute to MS pathogenesis by producing anti-myelin basic protein antibodies. In later studies, aberrant function of Treg and Th9 cells was identified as contributing to MS. This review summarizes the aberrant function and count of lymphocyte, and the contributions of these cell to the mechanisms of MS. Additionally, we have outlined the novel MS therapeutics aimed to amend the aberrant function or counts of these lymphocytes.

Age-period-cohort analysis of the incidence of multiple sclerosis over twenty years in Lorraine, France

Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system. An increase in MS incidence over time is reported in several regions of the world. We aimed to describe the evolution of the annual MS incidence in the Lorraine region, France, from 1996 to 2015 and to analyze potential components of a possible change by a temporal effect of age at MS onset, MS onset period, and birth cohort, overall and for each sex. Cases were identified from ReLSEP, a population-based registry of MS cases living in Lorraine, northeastern France, with MS onset between 1996 and 2015. Age-period-cohort modeling was used to describe trends in MS incidence. Annual age- and sex-standardized incidences were relatively stable: 6.76/100 000 population (95%CI [5.76-7.91]) in 1996 and 6.78/100 000 (95%CI [5.72-7.97]) in 2015. The incidence ratio between women and men was 2.4. For all time periods, the peak incidence occurred between ages 25 and 35 years. Age-period-adjusted cohort and age-cohort-adjusted period analyses did not reveal a period or cohort effect. The incidence of MS remained stable over the study period in Lorraine, and we could not identify any particular effect of disease onset period or birth period on this evolution.

Use of geographical information systems in multiple sclerosis research: A systematic scoping review

INTRODUCTION

Geographical information system (GIS) and spatial analysis have an emerging role in the understanding and management of health-related outcomes. However, there is a knowledge gap about the extent to which GIS has supported multiple Sclerosis (MS) research. Therefore, this review aimed to explore the types of GIS applications and the complexity of their visualisation in MS research.

METHODS

A systematic scoping review was conducted based on York's five-stage framework. PubMed, Scopus and Web of Science were searched for relevant studies published between 2000 and 2020 using a comprehensive search strategy based on the main concepts related to GIS and MS. Grounded, inductive analysis was conducted to organize studies into meaningful application areas. Further, we developed a tool to assess the visualisation complexity of the selected papers.

RESULTS

Of 3,723 identified unique citations, 42 papers met our inclusion criteria for the final review. One or more of the following types of GIS applications were reported by these studies: (a) thematic mapping (37 papers); (b) spatial cluster detection (16 papers); (c) risk factors detection (16 papers); and (d) health access and planning (two papers). In the majority of studies (88%), the score of visualisation complexity was relatively low: three or less from the range of zero to six.

CONCLUSIONS

Although the number of studies using GIS techniques has dramatically increased in the last decade, the use of GIS in the areas of MS access and planning is still under-researched. Additionally, the capacity of GIS in visualising complex nature of MS care system is not yet fully investigated.

The Administrative Prevalence of Multiple Sclerosis in Greece on the Basis of a Nationwide Prescription Database

Objective: To estimate current prevalence of multiple sclerosis (MS) in Greece using administrative data from the nationwide medicine prescription database.

Methods: Prescription records of a 24-month period (June 2017–May 2019) were analyzed in order to identify cases of MS. Sex, age, and place of residence were recorded for each identified case. Prevalence of MS was calculated based on the updated records of the Greek population according to Hellenic Statistical Authority.

Results: The 2-year cumulative period prevalence of MS was estimated to 197.8 per 100,000 (95% CI 197.6–198.0). In total, 21,218 patients (65.8% female) were identified. During this period, the prevalence of MS was 138.7 per 100,000 (95% CI 138.4–139.0) in men and 253.6 per 100,000 (95% CI 253.3–254.1) in women. Prevalence was higher in the 45–49 age group in both sexes. Analysis of the place of residence revealed higher prevalence in the Attica region and Western Greece while lower prevalence was observed in Northern Greece. No north–south latitude gradient was detected. Point prevalence on 1 January 2019 was calculated to 188.9 per 100,000 (95% CI 188.7–189.1). Regarding treatment, 73.1% of the identified cases received at least once a Disease Modifying Drug.

Conclusions: According to this national-level study conducted in Greece, estimated prevalence of MS was found to be similar to those of other European countries. Heterogeneity of MS prevalence across the country was observed and needs further investigation.

Pediatric multiple sclerosis: from clinical basis to imaging spectrum and differential diagnosis

Pediatric multiple sclerosis (MS) deserves special attention because of its impact on cognitive function and development. Although knowledge regarding pediatric MS has rapidly increased, understanding the peculiarities of this population remains crucial for disease management. There is limited expertise about the efficacy and safety of current disease-modifying agents. Although pathophysiology is not entirely understood, some risk factors and immunological features have been described and are discussed herein. While the revised International Pediatric MS Study Group diagnostic criteria have improved the accuracy of diagnosis, the recently revised McDonald criteria also offer some new insights into the pediatric population. It is fundamental that radiologists have strong knowledge about the vast spectrum of demyelinating disorders that can occur in childhood to ensure appropriate diagnosis and provide early treatment.

The changing course of multiple sclerosis: rising incidence, change in geographic distribution, disease course, and prognosis

PURPOSE OF REVIEW

This review provides a brief update of new research findings on the changing epidemiology, disease course, and prognosis of multiple sclerosis (MS).

RECENT FINDINGS

Evidence not only continues to support the female predominance in incidence and prevalence of the disease but also supports an increase in incidence of MS in geographic areas that were previously considered to be low incidence for the disease.

SUMMARY

An increased interest in population-based registries and databases will provide more valid epidemiological measures and observational studies conducted in well-defined study populations. Such studies are crucial for an accurate description of both changing prognosis of MS and differential characteristics of the various MS phenotypes.

Five-year outcome in the copaxone observatory: a nationwide cohort of patients with multiple sclerosis starting treatment with glatiramer acetate in France

The benefits provided by disease-modifying treatments in multiple sclerosis have been demonstrated in clinical trials, but the extent to which they can be extrapolated to everyday care is less clear, as are the long-term benefits of treatment. The objective of this prospective observational cohort study performed in France was to evaluate the effectiveness and safety of glatiramer acetate in patients with relapsing–remitting multiple sclerosis over a 5-year period. All neurologists in France were invited to participate and enroll adult patients starting a first treatment with brand glatiramer acetate 20 mg. Given the observational nature of the study, no fixed study visits were imposed; consultations took place according to the investigator’s normal practice. Occurrence of disease exacerbations and adverse events was documented and neurological disability evaluated with the EDSS at each consultation. Overall, 852 patients were analysable and 269 took glatiramer acetate continuously for 5 years. Median treatment duration was 3.4 years. Principal reasons for discontinuation were inadequate efficacy (38.9%), local tolerability (22.6%) and personal convenience (21.3%). Age, employment status, baseline EDSS score and number of previous exacerbations were variables associated with treatment persistence. The annualised exacerbation rate (5 years) was 0.41 [95% CI 0.39–0.44]; 316 patients (37.2%) remained exacerbation-free throughout. The risk of confirmed disability worsening (5 years) was 43.8% [95% CI 39.9–47.9%]. The most frequent adverse drug reactions were local injection site reactions (584 patients; 68.5%) and systemic immediate post-injection reactions (168 patients; 19.7%). Overall, these findings are consistent with those of previous clinical trials.

The Interaction between Viral and Environmental Risk Factors in the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic debilitating inflammatory disease of unknown ethology targeting the central nervous system (CNS). MS has a polysymptomatic onset and is usually first diagnosed between the ages of 20–40 years. The pathology of the disease is characterized by immune mediated demyelination in the CNS. Although there is no clinical finding unique to MS, characteristic symptoms include sensory symptoms visual and motor impairment. No definitive trigger for the development of MS has been identified but large-scale population studies have described several epidemiological risk factors for the disease. This list is a confusing one including latitude, vitamin D (vitD) levels, genetics, infection with Epstein Barr Virus (EBV) and endogenous retrovirus (ERV) reactivation. This review will look at the evidence for each of these and the potential links between these disparate risk factors and the known molecular disease pathogenesis to describe potential hypotheses for the triggering of MS pathology.

[Indications and follow-up for autologous hematopoietic stem cell transplantation in multiple sclerosis: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) in association with the Francophone Society of Multiple Sclerosis]

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) organized the 8th allogeneic hematopoietic stem cell transplantation clinical practices harmonization workshop series in September 2017 in Lille, France. In this article we give the indications of autologous stem cell transplantation in multiple sclerosis as well as recommendations regarding post-transplant follow-up of patients under the hospice of the SFGM-TC and the Francophone Society of Multiple Sclerosis.

Estimated Incidence Rate of Multiple Sclerosis and Its Relationship with Geographical Factors in Isfahan Province between the Years 2001 and 2014

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disease associated with inflammation of the central nervous system in humans. This disease is the most common neurological disease, especially in young people. Various factors, including biological, genetic, and environmental factors, are effective on the prevalence of MS disease. This study intends to determine the relationship between geographical factors, and the prevalence of MS disease was performed.

METHODS

This ecological study was carried out on 2000 patients with diagnosis of MS during the years 2001-2014 in Isfahan province. All patients' data including age, sex, marital status, year, and location of patients were extracted from the files. Arc geographic information systems version 10.3 software was used for geographical maps, and for statistical analysis of data, SPSS.16 software ANOVA tests, independent t-test, and Kruskal-Wallis were used.

RESULTS

Based on recorded cases of MS, the highest and lowest cumulative incidence of diseases was related to the city of Isfahan (75.92 in one hundred thousand) and Aran Bidgol (1.16 in one hundred thousand), respectively. A significant relationship was observed between the incidence and height above sea level (P = 0.001), the average annual rainfall (P = 0.001), and land use (P = 0.001). With increase in the height above sea level and the average annual precipitation, the incidence of disease decreased.

CONCLUSIONS

MS disease incidence is high in Isfahan province. The distribution of the disease is not the same in the cities of this province, and some cities have a higher incidence. Furthermore, the incidence of the disease is influenced by geographical factors such as height above sea level, average annual rainfall, and land use. Therefore, it is recommended that relevant authorities by the implementation of screening programs in high-risk areas take action to identify and treat patients in the early stages.

Digital epidemiology confirms a latitude gradient of MS in France

BACKGROUND

A gradient of prevalence of MS has been previously reported, and this may be due to different environmental and genetic features of the different populations, but also to methodological issues. In France, for example, three studies analysed the presence of such a gradient with conflicting results. The aim of this study was to assess whether digital epidemiology could confirm the presence of such a gradient.

METHODS

through Google Trends, we analysed the relative search volume (RSV) for 'multiple sclerosis' in France, from 2004 to 2017, and assessed if an association with the decimal degree of latitude existed.

RESULTS

Latitude was correlated with crude RSV (r² 0.39, p 0.04) in the 21 regions considered, with a southwest/northeast gradient. A multiple linear regression model adjusted for sex and age confirmed the existence of such a latitudinal effect, with an increase of 2.43 RSV units for each unit increase in latitude (95% CIs 0.62-4.24, p < 0.01, adjusted r² 0.61).

CONCLUSIONS

our study provides additional evidence for the existence of a latitude gradient in MS, and the value of Internet-acquired data as real-time surveillance tools and alerts for healthcare systems.

Small-area distribution of multiple sclerosis incidence in western France: in search of environmental triggers

BACKGROUND

Despite intensive research over several decades, the etiology of multiple sclerosis (MS) remains poorly understood, although environmental factors are supposedly implicated. Our goal was to identify spatial clusters of MS incident cases at the small-area level to provide clues to local environmental risk factors that might cause or trigger the disease.

METHODS

A population-based and multi-stage study was performed in the French Brittany region to accurately ascertain the clinical onset of disease during the 2000-2004 period. The municipality of residence at the time of clinical onset was geocoded. To test for the presence of MS incidence clusters and to identify their approximate locations, we used a spatial scan statistic. We adjusted for socioeconomic deprivation, known to be strongly associated with increased MS incident rates, and scanned simultaneously for areas with either high or low rates. Sensitivity analyses (focusing on relapsing-remitting forms and/or places of residence available within the year following clinical onset) were performed.

RESULTS

A total of 848 incident cases of MS were registered in Brittany, corresponding to a crude annual incidence rate of 5.8 per 100,000 inhabitants. The spatial scan statistic did not find a significant cluster of MS incidence in either the primary analysis (p value ≥ 0.56) or in the sensitivity analyses (p value ≥ 0.16).

CONCLUSION

The findings of this study indicate that MS incidence is not markedly affected across space, suggesting that in the years preceding the first clinical expression of the disease, no environmental trigger is operative at the small-area population level in the French Brittany region.

Prevalence and mortality of patients with multiple sclerosis in France in 2012: a study based on French health insurance data

Data on the prevalence of multiple sclerosis (MS) in France are scarce. National and regional updated estimates are needed to better plan health policies. In this nationwide study, we provided estimates of the prevalence of MS in France in 2012 and mortality rate in 2013. MS cases were identified in the French national health insurance database (SNIIRAM-PMSI) using reimbursement data for disease-modifying treatment, long-term disease status for MS, disability pension for MS, and hospitalisation for MS (MS ICD-10 code: G35). We identified 99,123 MS cases, corresponding to an overall crude prevalence rate of 151.2 per 100,000 inhabitants [95% confidence interval (CI) 150.3-152.2]: 210.0 per 100,000 in women (95% CI 208.4-211.5) and 88.7 per 100,000 in men (95% CI 87.6-89.7). The overall prevalence rate was 155.6 per 100,000 inhabitants (95% CI 154.7-156.6) after standardization on the 2013-European population. We observed a prevalence gradient with a higher prevalence (190-200 per 100,000) in North-Eastern France and a lower prevalence in Southern and Western France (126-140). The crude mortality rate in 2013 was 13.7 per 1,000 MS cases (11.4 in women and 20.3 in men). The standardized mortality ratio was 2.56 (95% CI 2.41-2.72). Our results revise upwards the estimation of MS prevalence in France and confirm the excess mortality of MS patients compared to the general population.

[Identification of neurodegenerative diseases in administrative databases in France: A systematic review of the literature]

BACKGROUND

Given the health, social and economic burden of neurodegenerative diseases (ND), the development of epidemiologic studies is required. Administrative databases, such as the French national health insurance database (SNIIRAM) could represent an opportunity for researchers. ND could be presumed from drug reimbursement data, hospital stays or registration of a chronic condition. The aim of this study was to describe, in French administrative databases, algorithms used to identify Alzheimer's disease and associated disorders (ADAD), Parkinson's disease and associated disorders (PDAD), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS).

METHODS

A systematic literature review was performed in Medline and gray literature through December 31th, 2015. French studies focusing on ADAD, PDAD, MS or ALS as a primary health outcome, conducted among one of the SNIIRAM data sources (outpatient reimbursements, chronic condition registration, hospital discharge) were included.

RESULTS

Thirty-four studies were included (ADAD, n=18, PDAD, n=9, MS, n=4, ALS, n=3), leading to 36 algorithms. For each studied ND, there was an important variability in the algorithms, concerning (i) the type of criteria used (administrative database versus multi-source systems); (ii) the number of criteria used; (iii) the definition used for each criteria. The extent and level of drug exposure highly varied. Identification through hospitalizations showed variations in terms of type of stay (short stay, long-term stay, psychiatric ward…), extent of diagnosis codes used, diagnosis type (principal, related, associated diagnosis) and period used. A validation study was conducted for 2 out of 36 algorithms (PDAD), and criteria completeness was estimated for 3 algorithms (MS, ALS).

CONCLUSION

Despite the increase in ND identification among French administrative databases, few algorithms have been validated. Validation studies should be encouraged.

The Skin-Brain Connection Hypothesis, Bringing Together CCL27-Mediated T-Cell Activation in the Skin and Neural Cell Damage in the Adult Brain

Recent discovery of an association of low serum melatonin levels with relapse in multiple sclerosis (MS) opens a new horizon in understanding the pathogenesis of this disease. Skin is the main organ for sensing seasonal changes in duration of sunlight exposure. Level of melatonin production is dependent on light exposure. The molecular mechanisms connecting peripheral (skin) sensing of the light exposure and developing brain inflammation (MS) have not been investigated. We hypothesize that there is a connection between the reaction of skin to seasonal changes in sunlight exposure and the risk of MS and that seasonal changes in light exposure cause peripheral (skin) inflammation, the production of cytokines, and the subsequent inflammation of the brain. In skin of genetically predisposed individuals, cytokines attract memory cutaneous lymphocyte-associated antigen (CLA+) T lymphocytes, which then maintain local inflammation. Once inflammation is resolved, CLA+ lymphocytes return to the circulation, some of which eventually migrate to the brain. Once in the brain these lymphocytes may initiate an inflammatory response. Our observation of increased CC chemokine ligand 27 (CCL27) in MS sera supports the involvement of skin in the pathogenesis of MS. Further, the importance of our data is that CCL27 is a chemokine released by activated keratinocytes, which is upregulated in inflamed skin. We propose that high serum levels of CCL27 in MS are the result of skin inflammation due to exposure to seasonal changes in the sunlight. Future studies will determine whether CCL27 serum level correlates with seasonal changes in sunlight exposure, MS exacerbation, and skin inflammation.

Geographical Heterogeneity of Multiple Sclerosis Prevalence in France

Introduction

Geographical variation in the prevalence of multiple sclerosis (MS) is controversial. Heterogeneity is important to acknowledge to adapt the provision of care within the healthcare system. We aimed to investigate differences in prevalence of MS in departments in the French territory.

Methods

We estimated MS prevalence on October 31, 2004 in 21 administrative departments in France (22% of the metropolitan departments) by using multiple data sources: the main French health insurance systems, neurologist networks devoted to MS and the Technical Information Agency of Hospitalization. We used a spatial Bayesian approach based on estimating the number of MS cases from 2005 and 2008 capture–recapture studies to analyze differences in prevalence.

Results

The age- and sex-standardized prevalence of MS per 100,000 inhabitants ranged from 68.1 (95% credible interval 54.6, 84.4) in Hautes-Pyrénées (southwest France) to 296.5 (258.8, 338.9) in Moselle (northeast France). The greatest prevalence was in the northeast departments, and the other departments showed great variability.

Discussion

By combining multiple data sources into a spatial Bayesian model, we found heterogeneity in MS prevalence among the 21 departments of France, some with higher prevalence than anticipated from previous publications. No clear explanation related to health insurance coverage and hospital facilities can be advanced. Population migration, socioeconomic status of the population studied and environmental effects are suspected.

The etiopathogenesis of diffuse low-grade gliomas

The origins of diffuse low-grade gliomas (DLGG) are unknown. Beyond some limited data on their temporal and cellular origins, the mechanisms and risk factors involved are poorly known. First, based on strong relationships between DLGG development and the eloquence of brain regions frequently invaded by these tumors, we propose a "functional theory" to explain the origin of DLGG. Second, the biological pathways involved in DLGG genesis may differ according to tumor location (anatomo-molecular correlations). The cellular and molecular mechanisms of such "molecular theory" will be reviewed. Third, the geographical distribution of diffuse WHO grade II-III gliomas within populations is heterogeneous, suggesting possible environmental risk factors. We will discuss this "environmental theory". Finally, we will summarize the current knowledge on genetic susceptibility in gliomas ("genetic predisposition theory"). These crucial issues illustrate the close relationships between the pathophysiology of gliomagenesis, the anatomo-functional organization of the brain, and personalized management of DLGG patients.

Prospective evaluation of antibiotic treatment for urological procedure in patients presenting with neurogenic bladder

OBJECTIVES

Patients presenting with neurogenic bladder often require urological procedures (urodynamic testing and botulinum toxin injections) and a preventive antibiotic therapy. We aimed to assess the efficacy of this little known strategy in a cohort of patients.

PATIENTS AND METHODS

All patients presenting with neurogenic bladder who underwent urological procedure were included in the study. They received an antibiotic therapy in accordance with the urine cytobacteriological examination results. The antibiotic therapy was initiated two days before the procedure and prolonged up until two days after the procedure if the culture was positive. Patients were treated with a single dose of fosfomycin-trometamol in case of a negative culture. The main study outcome was the occurrence of urinary tract infection (UTI), defined by a positive urine culture and symptoms, up until 14 days after the procedure.

RESULTS

A total of 80 urological procedures were performed. Mean patient age was 47±13.1 years (sex ratio 1.22); 59 (73.8%) presented with asymptomatic bacteriuria before the procedure. Nine (11.1%) UTIs were recorded on Day 14, of which one (1.2%) was febrile. Two patients required an additional curative antibiotic therapy. No patient was hospitalized. Overall, 77.8% of UTIs were cured without antibiotic therapy.

CONCLUSION

Screening and treating asymptomatic bacteriuria before urological procedures seems unnecessary and vainly exposes this population at high risk of infectious diseases to antibiotic therapies. This data should be confirmed by a randomized clinical trial.

Sunshine, Sea, and Season of Birth: MS Incidence in Wales

Maternal sun exposure in gestation and throughout the lifetime is necessary for vitamin D synthesis, and living near the sea is a population level index of seafood consumption. The aim of this study was to estimate the incidence rate of multiple sclerosis (MS) in Wales and examine its association with sun exposure, coastal living, and latitude. The study used a database of MS hospital visits and admissions in Wales between 2002 and 2013. For the 1,909 lower layer super output areas (LSOAs) in Wales, coastal status, population, longitude/latitude, and average sunshine hours per day were obtained. Age-specific and age-standardised MS incidence were calculated and modelled using Poisson regression. The distribution of births by month was compared between MS cases and the combined England and Wales population. There were 3,557 new MS cases between 2002 and 2013, with an average annual incidence of 8.14 (95% CI: 7.69–8.59) among males and 12.97 (95% CI: 12.44–13.50) among females per 100,000 population. The female-to-male ratio was 1.86:1. For both sexes combined, the average annual incidence rate was 9.10 (95% CI: 8.80–9.40). All figures are age-standardized to the 1976 European standard population. Compared to the combined England and Wales population, more people with MS were born in April, observed-to-expected ratio: 1.21 (95% CI: 1.08–1.36). MS incidence varied directly with latitude and inversely with sunshine hours. Proximity to the coast was associated with lower MS incidence only in easterly areas. This study shows that MS incidence rate in Wales is comparable to the rate in Scotland and is associated with environmental factors that probably represent levels of vitamin D.

Short-term population-based non-linear concentration-response associations between fine particulate matter and respiratory diseases in Taipei (Taiwan): a spatiotemporal analysis

Fine particulate matter <2.5 μm (PM2.5) has been associated with human health issues; however, findings regarding the influence of PM2.5 on respiratory disease remain inconsistent. The short-term, population-based association between the respiratory clinic visits of children and PM2.5 exposure levels were investigated by considering both the spatiotemporal distributions of ambient pollution and clinic visit data. We applied a spatiotemporal structured additive regression model to examine the concentration-response (C-R) association between children's respiratory clinic visits and PM2.5 concentrations. This analysis was separately performed on three respiratory disease categories that were selected from the Taiwanese National Health Insurance database, which includes 41 districts in the Taipei area of Taiwan from 2005 to 2007. The findings reveal a non-linear C-R pattern of PM2.5, particularly in acute respiratory infections. However, a PM2.5 increase at relatively lower levels can elevate the same-day respiratory health risks of both preschool children (<6 years old) and schoolchildren (6-14 years old). In preschool children, same-day health risks rise when concentrations increase from 0.76 to 7.44 μg/m(3), and in schoolchildren, same-day health risks rise when concentrations increase from 0.76 to 7.52 μg/m(3). Changes in PM2.5 levels generally exhibited no significant association with same-day respiratory risks, except in instances where PM2.5 levels are extremely high, and these occurrences do exhibit a significant positive influence on respiratory health that is especially notable in schoolchildren. A significant high relative rate of respiratory clinic visits are concentrated in highly populated areas. We highlight the non-linearity of the respiratory health effects of PM2.5 on children to investigate this population-based association. The C-R relationship in this study can provide a highly valuable alternative for assessing the effects of ambient air pollution on human health.

Geographic variations of multiple sclerosis prevalence in France: The latitude gradient is not uniform depending on the socioeconomic status of the studied population

Background

In France, two studies analysed multiple sclerosis prevalence nationwide: one was carried out in farmers, and the other one in employees. A south-north gradient of prevalence was found solely in farmers.

Objective

In order to better describe the latitude gradient in France, which is not uniform depending on the studied population, we assessed whether a gradient exists in another population than farmers and employees: independent workers. The same methods of case ascertainment have been used.

Methods

Altogether 4,165,903 persons insured by the French health insurance scheme for independent workers were included. We searched the database for (a) long term disease status ‘multiple sclerosis’, (b) domicile, (c) gender and (d) age.

Results

A total of 4182 cases of multiple sclerosis were registered giving a prevalence of 100.39/100,000. Adjustment by age and sex and spatial smoothing with a Bayesian analysis showed a gradual increase of prevalence from the southwest to the northeast of France. Standardised morbidity ratio was correlated with latitude and longitude (p<0.0001; p = 0.0031; adjusted R²= 0.3038).

Conclusion

A discrepancy of geographic distribution between farmers and independent workers on the one hand and employees on the other cannot be attributable to environment. Assuming that socioeconomic status by itself is not associated with multiple sclerosis risk, employees’ geographic mobility at adulthood for professional reasons could have interfered with the gradient effect.

Excess Mortality in Patients with Multiple Sclerosis Starts at 20 Years from Clinical Onset: Data from a Large-Scale French Observational Study

BACKGROUND

Recent studies in multiple sclerosis (MS) showed longer survival times from clinical onset than older hospital-based series. However estimated median time ranges widely, from 24 to 45 years, which makes huge difference for patients as this neurological disease mainly starts around age 20 to 40. Precise and up-to-date reference data about mortality in MS are crucial for patients and neurologists, but unavailable yet in France.

OBJECTIVES

Estimate survival in MS patients and compare mortality with that of the French general population.

METHODS

We conducted a multicenter observational study involving clinical longitudinal data from 30,413 eligible patients, linked to the national deaths register. Inclusion criteria were definite MS diagnosis and clinical onset prior to January, 1st 2009 in order to get a minimum of 1-year disease duration.

RESULTS

After removing between-center duplicates and applying inclusion criteria, the final population comprised 27,603 MS patients (F/M sex ratio 2.5, mean age at onset 33.0 years, 85.5% relapsing onset). During the follow-up period (mean 15.2 +/- 10.3 years), 1569 deaths (5.7%) were identified; half related to MS. Death rates were significantly higher in men, patients with later clinical onset, and in progressive MS. Overall excess mortality compared with the general population was moderate (Standardized Mortality Ratio 1.48, 95% confidence interval [1.41-1.55]), but increased considerably after 20 years of disease (2.20 [2.10-2.31]).

CONCLUSIONS

This study revealed a moderate decrease in life expectancy in MS patients, and showed that the risk of dying is strongly correlated to disease duration and disability, highlighting the need for early actions that can slow disability progression.

Register-based incidence of multiple sclerosis in Brittany (north-western France), 2000-2001

OBJECTIVES

To report on multiple sclerosis (MS) incidence in Brittany, north-western France.

MATERIALS & METHODS

From 2000, we set up a population-based register for patients presenting a putative incident MS (PIMS), that is first symptoms compatible with MS onset. We used 3 medical sources of case ascertainment (neurologists, CSF, regional MS-Clinic). Eligibility criteria required both clinical onset and being permanent resident of Brittany in 2000 or 2001. From 2010, all medical records were tracked, the 10-year follow-up allowing previously reported data to be updated.

RESULTS

Of 313 eligible PIMS, there were 208 definite MS (both McDonald and Poser criteria), 41 CIS-probable MS (Poser criteria), 32 CIS-possible MS and 32 non-MS. Our incident cohort of 249 MS cases with definite/probable MS (sex ratio 2.95) gave a crude annual incidence of 4.28 per 100,000 inhabitants (6.22 for women, 2.23 for men), and age-standardized rates (adjustment to the European population) of 4.41 [3.32-5.51], 6.68 [4.75-8.60], and 2.21 [1.12-3.31], respectively. Age-specific rates by gender and initial course showed that attack onset MS peaked at 25-29 years and progressive onset MS at 40-44 years in women (20-24 years and 45-49 years in men, respectively).

CONCLUSIONS

Brittany is confirmed a high-risk region for MS. Our data show marked differences in sex-specific pattern of MS incidence by clinical course and point out 25- to 29-year-old women as having the highest MS risk. While temporal variations cannot be excluded, comparison with overall French data suggests that other factors rather than latitude may influence the MS risk in France.

Cognitive impairment in a population-based study of patients with multiple sclerosis: differences between late relapsing-remitting, secondary progressive and primary progressive multiple sclerosis

BACKGROUND AND PURPOSE

Few studies have investigated the differences in cognitive skills between the three subtypes of multiple sclerosis (MS) and they confounded the course of the disease with the duration of the disease and the physical disability. Moreover, they were not population based.

METHODS

This was a retrospective analysis of cognitive testing from the database of a French programme for MS care. The pattern and the frequency of cognitive impairment in secondary progressive (SP), primary progressive (PP) and late relapsing-remitting (LRR, disease duration of more than 10 years) MS were compared.

RESULTS

A total of 101 patients with MS (41 LRRMS, 37 SPMS, 23 PPMS) were included. 63.0% had a significant cognitive impairment. After controlling for age, sex, Expanded Disability Status Scale, disease duration and education level, patients with SPMS were at least 2-fold more frequently impaired than patients with LLRMS in information processing speed (P = 0.005), executive functions (P = 0.04), verbal fluency (P = 0.02), verbal episodic memory (P = 0.04), working memory (P = 0.02) and visuospatial construction (P = 0.01). The number of patients with at least one or two deficient cognitive domain(s) was higher in the SPMS group than in the LRRMS group (P = 0.002 and P < 0.001). Patients with PPMS were more frequently impaired in verbal fluency (P = 0.046) than patients with LRRMS and they more often presented at least one impaired cognitive domain (P = 0.03). SPMS and PPMS groups differed only for visuospatial construction (P = 0.02).

CONCLUSION

In this population-based study, patients with a progressive subtype of MS were more frequently and more severely impaired than patients with RRMS, even after more than 10 years of disease.

Treatment discontinuation in multiple sclerosis: The French Web-based survey ALLIANCE

Background

In multiple sclerosis (MS), treatment discontinuation leads to a higher risk of relapse, poorer quality of life and greater economic impact.

Objective

The objective of this work is to evaluate treatment discontinuation in MS, the reasons for this and the reasons for treatment resumption.

Methods

A French national Web-based survey was carried out between May and August 2011. A total of 602 MS patients answered a questionnaire on sociodemographic data, medical follow-up, disease-modifying therapies (DMTs), symptomatic treatments, care given, factors involved in treatment discontinuation and reasons for resuming treatment.

Results

Among 413 patients using DMTs, 54% have considered discontinuing their treatment, primarily because of anger (61%), side effects (61%) and fatigue (57%). Sixty-eight patients have actually discontinued their treatment because of side effects (43%), lack of observed outcomes (32%), exasperation (29%) or fatigue (29%). The reasons for symptomatic treatment discontinuation were fear of addiction (32%–46%) and lack of efficacy (28%–45%). Physiotherapy was discontinued because of fatigue (37%), stress (34%) or inefficiency (31%). According to patients, treatment discontinuation could have been prevented by psychological support, care team empathy and support from family.

Conclusion

The major factor that could prevent treatment discontinuation is psychological support. Initiating and monitoring treatment in MS leads to emotional and personality changes, requiring adaptations that may improve compliance.

Flexible modeling of disease activity measures improved prognosis of disability progression in relapsing-remitting multiple sclerosis

OBJECTIVES

To illustrate the advantages of updating time-varying measures of disease activity and flexible modeling in prognostic clinical studies using the example of the association between the frequency of past relapses and occurrence of ambulation-related disability in multiple sclerosis (MS).

STUDY DESIGN AND SETTING

Longitudinal population-based study of 288 patients from Burgundy, France, diagnosed with relapsing-remitting MS in 1990-2003. The end point was a nonreversible moderate MS disability (European Database for Multiple Sclerosis score ≥ 3.0 derived from Extended Disability Status Scale). Alternative time-varying measures of attacks frequency included (1) conventional number of early MS attacks in the first 2 years after diagnosis; and two new measures, continuously updated during the follow-up; (2) cumulative number of past attacks; and (3) number of recent attacks, during the past 2 years. Multivariate analyses used Cox proportional hazards model and its flexible generalization, which accounted for time-dependent changes in the hazard ratios (HRs) for different attack frequency measures.

RESULTS

HRs for all measures decreased significantly with increasing follow-up time. The proposed updated number of recent attacks improved model's fit to data, relative to alternative measures of attack frequency, and was associated with a statistically significantly increased hazard of developing ambulation-related MS disability in the next 2 years during the entire follow-up period.

CONCLUSION

Updated measures of recent disease activity, such as frequency of recent attacks and modeling of their time-dependent effects, may substantially improve prognosis of clinical outcomes, such as development of MS disability.

Multiple sclerosis in children: an update on clinical diagnosis, therapeutic strategies, and research

The clinical features, diagnostic challenges, neuroimaging appearance, therapeutic options, and pathobiological research progress in childhood-and adolescent-onset multiple sclerosis have been informed by many new insights in the past 7 years. National programmes in several countries, collaborative research efforts, and an established international paediatric multiple sclerosis study group have contributed to revised clinical diagnostic definitions, identified clinical features of multiple sclerosis that differ by age of onset, and made recommendations regarding the treatment of paediatric multiple sclerosis. The relative risks conveyed by genetic and environmental factors to paediatric multiple sclerosis have been the subject of several large cohort studies. MRI features have been characterised in terms of qualitative descriptions of lesion distribution and applicability of MRI aspects to multiple sclerosis diagnostic criteria, and quantitative studies have assessed total lesion burden and the effect of the disease on global and regional brain volume. Humoral-based and cell-based assays have identified antibodies against myelin, potassium-channel proteins, and T-cell profiles that support an adult-like T-cell repertoire and cellular reactivity against myelin in paediatric patients with multiple sclerosis. Finally, the safety and efficacy of standard first-line therapies in paediatric multiple sclerosis populations are now appreciated in more detail, and consensus views on the future conduct and feasibility of phase 3 trials for new drugs have been proposed.

Evolution of multiple sclerosis in France since the beginning of hepatitis B vaccination

Since the implementation of the mass vaccination campaign against hepatitis B in France, the appearance of multiple sclerosis, sometimes occurring in the aftermath of vaccinations, led to the publication of epidemiological international studies. This was also justified by the sharp increase in the annual incidence of multiple sclerosis reported to the French health insurance in the mid-1990s. Almost 20 years later, a retrospective reflection can be sketched from these official data and also from the national pharmacovigilance agency. Statistical data from these latter sources seem to show a significant correlation between the number of hepatitis B vaccinations performed and the declaration to the pharmacovigilance of multiple sclerosis occurring between 1 and 2 years later. The application of the Hill's criteria to these data indicates that the correlation between hepatitis B vaccine and multiple sclerosis may be causal.

Prevalence of multiple sclerosis in Csongrád County, Hungary

OBJECTIVE

Recent epidemiological studies were mainly based on the Poser or other diagnostic criteria. There have been no previous data from Hungary, which were assessed with the more up-to-date McDonald criteria and which give comparable standardized data from the region.

MATERIALS AND METHODS

Data were collected from the MS Register of the Department of Neurology at the University of Szeged. All possible and definitive patients with MS living in the county on the prevalence day were included in the study. Direct standardization was based on the European standard population.

RESULTS

On 1 January 2013, 379 registered patients with MS were alive in the county, that is, a crude MS prevalence of 89.8/100,000, 46.6/100,000 in males and 128.6/100,000 in females; standardized prevalence: 83.7/100,000 (42.3/100,000 for males, 122.6/100,000 for females). The distribution of the clinical forms: 11% clinically isolated syndrome, 69% relapsing-remitting form, 14% secondary progressive form, 6% primary progressive form. Patients with no or only mild symptoms comprised 91.9% of the relapsing-remitting population.

CONCLUSIONS

This is the first standardized epidemiological study based on the McDonald criteria in Central Europe. Hungary is a medium-risk country as concerns the prevalence of MS. The crude prevalence appears to have increased relative to previous reports from the county.

Acute increase of children's conjunctivitis clinic visits by Asian dust storms exposure - a spatiotemporal study in Taipei, Taiwan

Adverse health impacts of Asian dust storms (ADS) have been widely investigated and discussed in respiratory disease, but no study has examined the association between ADS events and their impact on eye diseases, especially in children. The impact of ADS events on the incidence of children's conjunctivitis is examined by analyzing the data from children's clinic visits registered in the 41 districts of Taipei area in Taiwan during the period 2002-2007. The structural additive regression modeling approach was used to assess the association between ADS events and clinic visits for conjunctivitis in children with consideration of day-of-the-week effects, temperature, and air quality levels. This study identifies an acute increase in the relative rate for children's conjunctivitis clinic visits during ADS periods with 1.48% (95% CI = 0.79, 2.17) for preschool children (aged <6 years old) and 9.48% (95% CI = 9.03, 9.93) for schoolchildren (aged ≥6 years old), respectively. The relative rates during post-ADS periods were still statistically significant, but much lower than those during ADS periods. The spatial analysis presents geographic heterogeneity of children's conjunctivitis clinic visits where higher relative rates were more likely observed in the most populated districts Compared to previous ADS studies related to respiratory diseases, our results reveals significantly acute impacts on children's conjunctivitis during ADS periods, and much influence on schoolchildren. Vulnerable areas were also identified in high density population.

Is it time for a new global classification of multiple sclerosis?

BACKGROUND

The geographic distribution of multiple sclerosis (MS) is classically divided into three zones based on frequency that were established by Kurtzke in the early 1970s. In recent years, an increasing number of epidemiological studies have shown significantly higher MS prevalence and incidence rates.

OBJECTIVE

The aim of this study was to review and update the geographic distribution of MS using incidence, prevalence and disease duration from the latest epidemiology surveys.

METHODS

We conducted a systematic review of articles on MS epidemiology published between January 1, 1990 and December 31, 2012.

RESULTS

MS studies were grouped by continent: the Americas, Europe, Asia, Australia/New Zealand, and Africa. A total of 101 studies were identified according to the inclusion criteria, and 58 reported incidence estimates. Globally, the median estimated incidence of MS was 5.2 (range: 0.5-20.6) per 100,000 p-yrs, the median estimated prevalence of MS was 112.0 (with a range of 5.2-335) per 100,000 p-yrs, and the average disease duration was 20.2 years (range: 7.6-36.2).

CONCLUSION

In the past few decades, the global prevalence and incidence patterns of MS have changed dramatically. Regardless of the reason of increasing prevalence and incidence rate, we suggest the need for a novel classification system based on global MS disease burden. Adopting such a system would improve economic efficiency and prioritization in health policy planning for MS.

[Multiple sclerosis and pelviperineology: Urinary and sexual dysfunctions and pregnancy]

GOAL

The aim was to review the literature on genito-urinary dysfunction in multiple sclerosis (MS).

MATERIAL

A literature review through the PubMed library until August, 31 2013 was carried out using the following keywords: multiple sclerosis and neurogenic bladder, neuropathic bladder, bladder, management, follow-up, urological complications, urological treatment, sexual dysfunction, female sexual function, male sexual function, erectile dysfunction, anorectal, faecal, constipation, bowel, pregnancy, parturition, delivery, breast-feeding.

RESULTS

Genito-urinary dysfunction is frequent in MS (35-90%) and may happen soon in the disease. Urinary symptoms (10-90%) are manifold resulting in a quality of life alteration and the onset of complications in 30% of the cases requiring a long-term follow-up. Sexual dysfunctions (35-87%) are also manifold affecting all the sexuality domains in men and women. Except the phosphodiesterase V inhibitors, few treatments have been assessed in this population. Pregnancy is nowadays considered as beneficial resulting in a disease slow-down and the lack of disease worsening despite an increase in disease relapse during the post-partum first quarter. It seems to be better to consider getting pregnant after at least one year without any relapse and to emphasize an exclusive breast-feeding.

CONCLUSION

Urinary and sexual dysfunctions are frequent in MS. A transdisciplinary approach including the neurologist and pelviperineology specialists facilitates a disability adapted early management.