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Objective: Elevated healthcare use before multiple sclerosis (MS) onset suggests earlier opportunity to identify MS. Yet their timing and sociodemographic effects are unclear. We examined rates of healthcare use (and by age/sex) for >two decades pre-MS onset., Methods: We identified people with MS (PwMS) using administrative data from Canada (Ontario) and Sweden (1991-2020) ("administrative" cohort), and the Swedish MS Registry ("clinical" cohort). The first MS/demyelinating diagnostic code (administrative) or symptom onset (clinical) defined MS onset. We compared annual rates of healthcare use (hospital, physician, and emergency-room [ED]) pre-onset between PwMS and up to five matched population controls using negative binomial regression, and by age/sex., Results: The administrative cohort = 35,018/136,007 PwMS/controls (Ontario), and 10,269/51,297 (Sweden). Rates of healthcare use were higher for PwMS than controls up to 28 (of 29) years (Ontario) and up to 15 (of 19) years (Sweden) pre-onset. Annual healthcare use rose steadily as onset approached, particularly escalating 7 years pre-onset in Ontario (e.g., hospital visit rate ratios [RRs] exceeded 1.30), and 6 years in Sweden (physician visit RRs > 1.10). RRs peaked the year pre-onset (ED visits [Ontario] = 3.04; 95% CI: 2.94-3.13, physician visits [Sweden] = 2.51; 95% CI: 2.44-2.59). In the year pre-onset, RRs were disproportionately higher for males (ED RRs [Ontario] = 3.30; 95% CI: 3.13-3.48 vs. females = 2.90; 95% CI: 2.79-3.02), and dropped steadily by age (physician visit RRs [Sweden] = 2.61/2.27/1.97/1.72 for 50/40/30/20-year-olds). The smaller clinical cohort (7604/37,974 PwMS/controls) exhibited similar patterns, albeit more modest, with RRs elevated up to 5 years pre-onset (physician visit RR [year-5] = 1.08; 95% CI: 1.02-1.14; RR [year-1] = 1.39;1.33-1.46)., Interpretation: Higher healthcare use was evident decades before MS onset, escalating 6-7 years pre-onset, peaking the year before, being disproportionately higher for males and older PwMS., (© 2024 The Author(s). Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Background: Women have a higher risk of developing multiple sclerosis (MS), potentially due to hormonal factors. Elevated testosterone levels, common in polycystic ovary syndrome (PCOS), might influence MS risk., Objective: To investigate the relationship between PCOS, as a proxy for elevated testosterone levels, and MS risk through phenotypic and genomic analysis., Methods: Cox regression models analysed the association between PCOS and MS risk. The genome-wide cross-trait analysis examined the genetic architecture., Results: In a Swedish cohort of 1,374,529 women, 77 (0.3%) with PCOS and 3,654 (0.3%) without PCOS were diagnosed with MS. After adjusting for birth year and obesity, no association was found between PCOS and MS ( HR = 0.91, 95% CI = 0.72-1.15), which was confirmed by Mendelian randomization analysis, where genetically predicted PCOS propensity, sex hormone-binding globulin (SHBG), or testosterone levels did not causally affect MS risk (all p -values > 0.05). By exploring horizontal pleiotropy, we identified shared genetic regions and 19 independent pleiotropic SNPs for SHBG with MS and 11 for testosterone with MS., Conclusion: We did not find evidence for a causal role of PCOS, as a proxy of elevated testosterone, in reducing the risk of MS in women. The shared genetic loci between testosterone, SHBG, and MS provide biological insights., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Epstein-Barr virus (EBV) infection has been advocated as a prerequisite for developing multiple sclerosis (MS) and possibly the propagation of the disease. However, the precise mechanisms for such influences are still unclear. A large-scale study investigating the host genetics of EBV serology and related clinical manifestations, such as infectious mononucleosis (IM), may help us better understand the role of EBV in MS pathogenesis. This study evaluates the host genetic factors that influence serological response against EBV and history of IM and cross-evaluates them with MS risk and genetic susceptibility in the Swedish population. Plasma IgG antibody levels against EBV nuclear antigen-1 [EBNA-1, truncated = amino acids (aa) (325-641), peptide = aa(385-420)] and viral capsid antigen p18 (VCAp18) were measured using bead-based multiplex serology for 8744 MS cases and 7229 population-matched control subjects. The MS risk association for high/low EBV antibody levels and history of IM was compared to relevant clinical measures along with sex, age at sampling, and associated HLA allele variants. Genome-wide and HLA allele association analyses were also performed to identify genetic risk factors for EBV antibody response and IM history. Higher antibody levels against VCAp18 [odds ratio (OR) = 1.74, 95% confidence interval (CI) = 1.60-1.88] and EBNA-1, particularly the peptide (OR = 3.13, 95% CI = 2.93-3.35), were associated with an increased risk for MS. The risk increased with higher anti-EBNA-1 IgG levels up to 12× the reference risk. We also identified several independent HLA haplotypes associated with EBV serology overlapping with known MS risk alleles (e.g. DRB1*15:01). Although there were several candidates, no variants outside the HLA region reached genome-wide significance. Cumulative HLA risk for anti-EBNA-1 IgG levels, particularly the peptide fragment, was strongly associated with MS. In contrast, the genetic risk for high anti-VCAp18 IgG levels was not as strongly associated with MS risk. IM history was not associated with class II HLA genes but negatively associated with A*02:01, which is protective against MS. Our findings emphasize that the risk association between anti-EBNA-1 IgG levels and MS may be partly due to overlapping HLA associations. Additionally, the increasing MS risk with increasing anti-EBNA-1 levels would be consistent with a pathogenic role of the EBNA-1 immune response, perhaps through molecular mimicry. Given that high anti-EBNA-1 antibodies may reflect a poorly controlled T-cell defence against the virus, our findings would be consistent with DRB1*15:01 being a poor class II antigen in the immune defence against EBV. Last, the difference in genetic control of IM supports the independent roles of EBNA-1 and IM in MS susceptibility., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Background: While multiple sclerosis (MS) affects less than 1 % of the general population, immune mediated inflammatory diseases (IMIDs) collectively influence 5-10 % of the population. Understanding familial co-aggregation of MS and other IMIDs carries important clinical and public health implications that will enable early detection and personalized treatment., Objective: To estimate the familial association between MS and other IMIDs and to quantify their shared genetic basis., Design: Register-based multi-generational nested case-control familial co-aggregation study and genetic correlation study., Setting: Sweden., Participants: 24,995 individuals with MS matched with 253,870 controls and 1,283,502 first-degree relatives (mothers, fathers, full siblings, and offspring) for familial co-aggregation analysis; population of European ancestry for genetic correlation analysis., Measurements: Logistic regressions with adjustment for covariates were used to estimate the odds ratios (ORs) of developing MS in individuals with first-degree relatives diagnosed with IMIDs compared to those without such family history. Pairwise genome-wide genetic correlations were estimated with linkage-disequilibrium score regression., Results: We observed an OR for familial co-aggregation of MS of 1.09 (95 % confidence interval (95%CI) = 1.07-1.11) in families with IMIDs history compared to families without. The association remained broadly consistent after stratification by sex concordance of relative pairs and by kinships. 18 IMID subtypes showed a familial association with MS, 7 of which including other acute widespread myelin destruction, encephalitis or myelitis or encephalomyelitis, inflammatory bowel disease, autoimmune thyroid diseases, systemic lupus erythematosus, other inflammatory system diseases, and sarcoidosis withstood multiple correction. Genetic correlations further revealed a shared genetic basis between 7 IMID subtypes with MS., Conclusion: We demonstrated a modest familial co-aggregation of MS with several IMIDs, and such association is likely due to shared genetic factors., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Few studies have examined the effect of concomitant autoimmune diseases on multiple sclerosis (MS) disability worsening. We set out to examine whether concomitant Crohn's Disease (CD), Ulcerative Colitis (UC), or Type 1 Diabetes (T1D) affect MS disability worsening in a nationwide cohort of MS patients as defined by reaching expanded disability scale status (EDSS) scores 3.0, 4.0 and 6.0., Methods: Patients with MS onset between January 2004 and January 2019 were identified from the Swedish MS registry and the Swedish National Patient Register. Kaplan-Meier analysis was used to estimate the median time to reach sustained disability milestones. Adjusted Cox proportional hazard regression models were used to calculate the risk of reaching disability milestones among persons with and without CD, UC, or T1D., Results: Out of 8972 persons with MS, 88 (1.0 %) had T1D, 47 (0.8 %) had UC, and 78 (0.9 %) had CD. There was a significantly higher risk of disability progression, for persons with MS and T1D for reaching EDSS 6.0, hazard ratio (HR) = 2.21 (95 % confidence interval (CI) = 1.48 -3.31) and persons with MS and comorbid CD for reaching EDSS 3.0, HR = 2.30 (95 %CI = 1.74-3.04) and 4.0, HR = 1.59 (95 %CI = 1.09-2.32), and persons with MS and comorbid UC for reaching EDSS 3.0 HR = 1.57 (95 %CI = 1.15-2.14). As defined by Charlson's comorbidity index, the co-existence of other co-morbidities conferred a significant increase in the risk of reaching all endpoints, with HR ranging from 1.23 to 1.62., Conclusion: Comorbidity is associated with a significantly increased risk of reaching disability end-points, and T1D, CD, and UC increase the risk further. Thus, there appears to be a need for increased vigilance of comorbidites in persons with MS in order to optimise the long-term outcome of MS., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Objective: There has been interest in a possible negative association between HIV and multiple sclerosis (MS). We aimed to compare the risk of MS in a cohort of individuals living with HIV to that in the general population., Methods: Population-based health data were accessed for 2 cohorts of HIV-positive persons from Sweden and British Columbia, Canada. Incident MS was identified using MS registries or a validated algorithm applied to administrative data. Individuals with HIV were followed from 1 year after the first clinical evidence of HIV or the first date of complete administrative health data (Canada = April 1, 1992 and Sweden = January 1, 2001) until the earliest of incident MS, emigration, death, or study end (Canada = March 31, 2020 and Sweden = December 31, 2018). The observed MS incidence rate in the HIV-positive cohort was compared to the expected age-, sex-, calendar year-, income-specific, and region of birth-specific rates in a randomly selected sample of >20% of each general population. The standardized incidence ratio (SIR) for MS following the first antiretroviral therapy exposure ("ART-exposed") was also calculated., Results: The combined Sweden-Canada cohort included 29,163 (75% men) HIV-positive persons. During 242,248 person-years of follow-up, 14 incident MS cases were observed in the HIV-positive cohort, whereas 26.19 cases were expected. The SIR for MS in the HIV-positive population was 0.53 (95% confidence interval [CI] = 0.32-0.90). The SIR for MS following the first ART exposure was 0.55 (95% CI = 0.31-0.96)., Interpretation: This international population-based study demonstrated a lower risk of MS among HIV-positive individuals, and HIV-positive ART-exposed individuals. These findings provide support for further exploration into the relationship among HIV, ART, and MS. ANN NEUROL 2024;95:487-494., (© 2023 The Authors. Annals of Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Although evidence exists for a causal association between 25-hydroxyvitamin D (25(OH)D) serum levels, and multiple sclerosis (MS), the role of variation in vitamin D receptor (VDR) binding in MS is unknown. Here, we leveraged previously identified variants associated with allele imbalance in VDR binding (VDR-binding variant; VDR-BV) in ChIP-exo data from calcitriol-stimulated lymphoblastoid cell lines and 25(OH)D serum levels from genome-wide association studies to construct genetic instrumental variables (GIVs). GIVs are composed of one or more genetic variants that serve as proxies for exposures of interest. Here, GIVs for both VDR-BVs and 25(OH)D were used in a two-sample Mendelian Randomization study to investigate the relationship between VDR binding at a locus, 25(OH)D serum levels, and MS risk. Data for 13,598 MS cases and 38,887 controls of European ancestry from Kaiser Permanente Northern California, Swedish MS studies, and the UK Biobank were included. We estimated the association between each VDR-BV GIV and MS. Significant interaction between a VDR-BV GIV and a GIV for serum 25OH(D) was evidence for a causal association between VDR-BVs and MS unbiased by pleiotropy. We observed evidence for associations between two VDR-BVs (rs2881514, rs2531804) and MS after correction for multiple tests. There was evidence of interaction between rs2881514 and a 25(OH)D GIV, providing evidence of a causal association between rs2881514 and MS. This study is the first to demonstrate evidence that variation in VDR binding at a locus contributes to MS risk. Our results are relevant to other autoimmune diseases in which vitamin D plays a role., Competing Interests: Competing interests statement:The authors declare no competing interest.

Importance: Multiple sclerosis (MS) severity may be informed by premorbid sociodemographic factors., Objective: To determine whether premorbid education, income, and marital status are associated with future MS disability and symptom severity, independent of treatment, in a universal health care context., Design, Setting, and Participants: This nationwide observational cohort study examined data from the Swedish MS Registry linked to national population registries from 2000 to 2020. Participants included people with MS onset from 2005 to 2015 and of working age (aged 23 to 59 years) 1 year and 5 years preceding disease onset., Exposures: Income quartile, educational attainment, and marital status measured at 1 and 5 years preceding disease onset., Main Outcome and Measures: Repeated measures of Expanded Disability Status Scale (EDSS) scores and patient-reported Multiple Sclerosis Impact Scale (MSIS-29) scores. Models were adjusted for age, sex, relapses, disease duration, and treatment exposure. Secondary analyses further adjusted for comorbidity. All analyses were stratified by disease course (relapse onset and progressive onset)., Results: There were 4557 patients (mean [SD] age, 37.5 [9.3] years; 3136 [68.8%] female, 4195 [92.1%] relapse-onset MS) with sociodemographic data from 1-year preonset of MS. In relapse-onset MS, higher premorbid income and education correlated with lower disability (EDSS, -0.16 [95% CI, -0.12 to -0.20] points) per income quartile; EDSS, -0.47 [95% CI, -0.59 to -0.35] points if tertiary educated), physical symptoms (MSIS-29 physical subscore, -14% [95% CI, -11% to -18%] per income quartile; MSIS-29 physical subscore, -43% [95% CI, -35% to -50%] if tertiary educated), and psychological symptoms (MSIS-29 psychological subscore, -12% [95% CI, -9% to -16%] per income quartile; MSIS-29 psychological subscore, -25% [95% CI, -17% to -33%] if tertiary educated). Marital separation was associated with adverse outcomes (EDSS, 0.34 [95% CI, 0.18 to 0.51]; MSIS-29 physical subscore, 35% [95% CI, 12% to 62%]; MSIS-29 psychological subscore, 25% [95% CI, 8% to 46%]). In progressive-onset MS, higher income correlated with lower EDSS (-0.30 [95% CI, -0.48 to -0.11] points per income quartile) whereas education correlated with lower physical (-34% [95% CI, -53% to -7%]) and psychological symptoms (-33% [95% CI, -54% to -1%]). Estimates for 5-years preonset were comparable with 1-year preonset, as were the comorbidity-adjusted findings., Conclusions and Relevance: In this cohort study of working-age adults with MS, premorbid income, education, and marital status correlated with disability and symptom severity in relapse-onset and progressive-onset MS, independent of treatment. These findings suggest that socioeconomic status may reflect both structural and individual determinants of health in MS.

Background: The two main phenotypes of multiple sclerosis (MS), primary progressive (PPMS) and relapsing Onset (ROMS), show clinical and demographic differences suggesting possible differential risk mechanisms. Understanding the heritable features of these phenotypes could provide aetiological insight., Objectives: To evaluate the magnitude of familial components in PPMS and ROMS and to estimate the heritability of disease phenotypes., Methods: We used data from 25,186 MS patients of Nordic ancestry from the Swedish MS Registry between 1987 and 2019 with known disease phenotype (1593 PPMS and 16,718 ROMS) and 251,881 matched population-based controls and 3,364,646 relatives of cases and controls. Heritability was calculated using threshold-liability models. For familial odds ratios (ORs), logistic regression with robust sandwich estimator was utilized., Results: The OR of MS diagnosis in those with a first-degree family member with ROMS was 7.00 and 8.06 in those with PPMS. The corresponding ORs for having a second-degree family member with ROMS was 2.16 and 2.18 in PPMS. The additive genetic effect in ROMS was 0.54 and 0.22 in PPMS., Conclusion: Risk of MS increases by several folds in those with a relative with MS. The likelihood of developing either disease phenotype appears independent of genetic predisposition.

Background: Multiple sclerosis (MS) quality of care guidelines are consensus-based. The effectiveness of the recommendations is unknown., Objective: To determine whether clinic-level quality of care affects clinical and patient-reported outcomes., Methods: This nationwide observational cohort study included patients with adult-onset MS in the Swedish MS registry with disease onset 2005-2015. Clinic-level quality of care was measured by four indicators: visit density, magnetic resonance imaging (MRI) density, mean time to commencement of disease-modifying therapy, and data completeness. Outcomes were Expanded Disability Status Scale (EDSS) and patient-reported symptoms measured by the Multiple Sclerosis Impact Scale (MSIS-29). Analyses were adjusted for individual patient characteristics and disease-modifying therapy exposure., Results: In relapsing MS, all quality indicators benefitted EDSS and physical symptoms. Faster treatment, frequent visits, and higher data completeness benefitted psychological symptoms. After controlling for all indicators and individual treatment exposures, faster treatment remained independently associated with lower EDSS (-0.06, 95% confidence interval (CI): -0.01, -0.10) and more frequent visits were associated with milder physical symptoms (MSIS-29 physical score: -16.2%, 95% CI: -1.8%, -29.5%). Clinic-level quality of care did not affect any outcomes in progressive-onset disease., Conclusion: Certain quality of care indicators correlated to disability and patient-reported outcomes in relapse-onset but not progressive-onset disease. Future guidelines should consider recommendations specific to disease course.

Background: Timing of disease-modifying therapy affects clinical disability in multiple sclerosis, but it is not known whether patient reported outcomes are also affected. This study investigates the relationship between treatment timing and patient-reported symptoms and health-related quality of life., Methods: This was a nationwide observational cohort study of adults with relapsing multiple sclerosis, with disease onset between 2001 and 2016, and commenced on disease-modifying treatment within 4 years from disease onset. Patients commencing treatment within 0-2 years were compared with patients commencing treatment at 2-4 years. Indication bias was mitigated by propensity matching. Outcomes were patient-reported symptoms and health-related quality of life as measured by the Multiple Sclerosis Impact Scale (MSIS-29) and EuroQol-5 Dimensions-3 Level (EQ-5D). The follow-up period was 4-10 years from disease onset., Results: There were 2648 patients (69% female, median age 32.8) eligible for matching. Mean follow-up time was 3.7 years. Based on 780 matched patients, each year of treatment delay was associated with a worse MSIS physical score by 2.75 points (95% CI 1.29 to 4.20), and worse MSIS psychological score by 2.02 points (95% CI 0.03 to 3.78), in the adjusted models.Among 690 matched patients, earlier treatment start was not associated with EQ-5D score during the follow-up., Conclusions: Earlier commencement of disease-modifying treatment was associated with better patient-reported physical symptoms when measured using a disease-specific metric; however, general quality of life was not affected. This indicates that other factors may inform patients' overall quality of life., Competing Interests: Competing interests: TS received compensation for serving on scientific advisory boards, honoraria for consultancy and funding for travel from Biogen. JH has received honoraria for serving on advisory boards for Biogen, Celgene, Sanofi-Genzyme, Merck KGaA, Novartis and Sandoz and speaker’s fees from Biogen, Novartis, Merck KGaA, Teva and Sanofi-Genzyme; he has served as P.I. for projects, or received unrestricted research support from, Biogen, Celgene, Merck KGaA, Novartis, Roche and Sanofi-Genzyme., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Cognitive impairment occurs in 40%-70% of persons with multiple sclerosis (MS)., Objective: To examine the effectiveness of natalizumab compared with other disease-modifying treatments (DMTs) on improving cognition as measured by the Symbol Digit Modalities Test (SDMT)., Methods: Data were collected as part of Swedish nationwide phase IV surveillance studies (2007-2020). An increase in SDMT score by ⩾10% of the difference between maximum score possible (110) and the baseline value was defined as cognitive improvement. The likelihood of improvement was compared between natalizumab-treated individuals and individuals treated with other DMTs using mixed effect logistic regression. Trend in odds of improvement was investigated using slope analyses., Results: We included 2100 persons with relapsing-remitting MS treated with natalizumab and 2622 persons treated with other DMTs. At 6 months, 45% reached improvement. The natalizumab group showed largest odds of improvement during follow-up (odds ratio: 2.3, 95% confidence interval (CI): 1.5-3.5). The odds of improvement increased by 7% (95% CI: 6-7) per month of natalizumab treatment. The equivalent estimate was 4% (95% CI: 2-5) for other monoclonal antibodies and nonsignificant for oral or platform therapies., Conclusion: Treatment with natalizumab or other monoclonal antibodies is associated with a significantly faster likelihood of cognitive improvement than platform or oral DMTs.

Background: Neurofilament light (NfL) levels reflect inflammatory disease activity in multiple sclerosis (MS), but it is less clear if NfL also can serve as a biomarker for MS progression in treated patients without relapses and focal lesion accrual. In addition, it has not been well established if clinically effective treatment re-establishes an age and sex pattern for cerebrospinal fluid NfL (cNfL) as seen in controls, and to what degree levels are affected by disability level and magnetic resonance imaging (MRI) atrophy metrics., Methods: We included subjects for whom cNfL levels had been determined as per clinical routine or in clinical research, classified as healthy controls (HCs, n = 89), MS-free disease controls (DCs, n = 251), untreated MS patients (uMS; n = 296), relapse-free treated MS patients (tMS; n = 78), and ProTEct-MS clinical trial participants (pMS; n = 41)., Results: Using linear regression, we found a positive association between cNfL and age, as well as lower concentrations among women, in all groups, except for uMS patients. In contrast, disability level in the entire MS cohort, or T1 and T2 lesion volumes, brain parenchymal fraction, thalamic fraction, and cortical thickness in the pMS trial cohort, did not correlate with cNfL concentrations. Furthermore, the cNfL levels in tMS and pMS groups did not differ., Conclusions: In participants with MS lacking signs of inflammatory disease activity, disease modulatory therapy reinstates an age and sex cNfL pattern similar to that of control subjects. No significant association was found between cNfL levels and clinical worsening, disability level, or MRI metrics., (© 2022 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)

Background: The β-D-Mannuronic acid (M2000) as a novel immunosuppressive drug, patented (PCT/EP2017/067920), has shown positive effects in experimental model of multiple sclerosis (MS). In this study, our aim was to assess efficacy and safety outcomes in MS treated patients with mannuronic acid compared to the conventional drug., Methods: In a 6-month, randomized controlled, phase II trial, we enrolled patients who had secondary progressive multiple sclerosis (SPMS), were 21-54 years of age, with a score of 1-7 on the Expanded Disability Status Scale (EDSS), and who had at least one relapse in the previous 6 months. Patients were administered orally 1000 mg/day (two 500 mg/capsule daily) of M2000. Endpoints included changes in brain magnetic resonance imaging (MRI) measures and the EDSS score, as compared to the conventional drug (interferon beta-1a, interferon beta-1b)., Results: A total of 25 (92.5%) of the M2000 treated patients and 25 conventionally treated patients completed the study. M2000 had better performance compared to the conventional drug regarding to MRI-related measurements, however, the differences between groups were not statistically significant. M2000 decreased the disability progression over the 6-month period. The EDSS score was decreased in the M2000 treated group in the sixth month versus the conventional drug ( p  < 0.009). Furthermore, we did not observe any short-term side effects., Conclusions: As compared with the conventional drug, mannuronic acid (M2000) improved the rate of disability progression. This clinical trial demonstrated the efficacy and safety of mannuronic acid in patients with SPMS. (Registered Clinical Trials number, IRCT2016111313739N6).

Tobacco smoke is an important modifiable environmental risk factor for multiple sclerosis (MS) risk. The population attributable fraction (AF) of MS due to smoking can be used to assess the contribution of smoking to the risk of MS development. We conducted a matched case-control study, including individuals with MS and population-based controls. Overall, sex- and genetic risk score-stratified AF due to smoking were calculated by fitting logistic regression models. We included 9,419 individuals with MS and 9,419 population-based matched controls. At the time of MS onset 44.1% of persons with MS and 35.9% of controls ever regularly smoked of which 38.1% and 29.2% were still smoking. The overall AF was 13.1% (95%CI: 10.7 to 15.4). The AF was 10.6% (95%CI: 7.4 to 13.7) in females and 19.1% (95%CI: 13.1 to 25.1) in males. The AF was 0.6% (95%CI: 0.0 to 2) in ex-smokers. In those having human leucocyte antigen (HLA) and non-HLA risk scores above the median levels of controls, the AF was 11.4% (95%CI: 6.8 to 15.9) and 12% (95%CI: 7.7 to 16.3), respectively. The AF was 17.6% (95%CI: 10.2 to 24.9) and 18.6% (95%CI: 5.5 to 31.6) in those with HLA and non-HLA risk scores below the median levels in controls, respectively. We noticed a decline in AF in recent birth cohorts. This study indicates that at least 13% of cases of MS could be prevented through the avoidance of tobacco smoking. Considering the prevalence of MS, this represents a very large group of people in absolute number., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Manouchehrinia, Huang, Hillert, Alfredsson, Olsson, Kockum and Constantinescu.)

Objectives: Multiple sclerosis (MS) is a chronic neurodegenerative disease of the central nervous system. Identifying MS at the population level is important for disease surveillance and allocation of resources. The Swedish National Patient Registry (NPR) has been used to study the epidemiology of MS, but the accuracy of this resource is not known. We aimed to validate a definition of MS using the Swedish NPR in Värmland County using a longitudinal cohort design., Materials and Methods: Data were extracted from the NPR, the Total Population Register, the Swedish MS Register, and medical records for the years 2001-2013. Fifteen algorithms of hospitalizations and clinic visits for MS were developed and compared with findings in medical records, which acted as the "gold standard" definition. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were estimated., Results: Of 805 eligible persons identified in the NPR, 763 had MS (94.8%) according to medical records. Of these, 544 (71.3%) were also registered in the SMSreg. The case definition that had a well-balanced sensitivity and specificity required three or more clinic or hospital visits for MS (sensitivity of 85.3% (95% CI: 82.6-87.8) and specificity of 81.0% (95%CI: 65.9-91.4)., Conclusions: Multiple case definitions with high sensitivity and moderate specificity were found, suggesting that the NPR can be used to accurately identify persons with MS., (© 2021 The Authors. Acta Neurologica Scandinavica published by John Wiley & Sons Ltd.)

Depression is common in multiple sclerosis (MS); however, the underlying mechanism for the relationship remains unknown. In this study, we examined a putative causal relationship between depression and MS using a bidirectional Mendelian randomisation (MR) framework. Using the latest genome-wide association study data available, 168 non-major histocompatibility complex (MHC) independent variants associated with MS and 96 independent genetic variants associated with depression susceptibility were used. Maximum likelihood, weighted median, inverse variance weighted method and MR-Egger regression analyses were performed. There was no significant risk for the development of MS in persons carrying variants associated with depression or for risk of depression in individuals who are genetically susceptible to MS.

Background: Existing severity measurements in multiple sclerosis (MS) are often cross-sectional, making longitudinal comparisons of disease course between individuals difficult., Objective: The objective of this study is to create a severity metric that can reliably summarize a patient's disease course., Methods: We developed the nARMSS - normalized ARMSS (age-related MS severity score) over follow-up, using the deviation of individual ARMSS scores from the expected value and integrated over the corresponding time period. The nARMSS scales from -5 to +5; a positive value indicates a more severe disease course for a patient when compared to other patients with similar disease timings., Results: Using Swedish MS registry data, the nARMSS was tested using data at 2 and 4 years of follow-up to predict the most severe quartile during the subsequent period up to 10 years total follow-up. The metric used was area under the curve of the receiver operating characteristic (AUC-ROC). This resulted in measurements of 0.929 and 0.941. In an external Canadian validation cohort, the equivalent AUC-ROCs were 0.901 and 0.908., Conclusion: The nARMSS provides a reliable, generalizable and easily measurable metric which makes longitudinal comparison of disease course between individuals feasible.

Multiple sclerosis (MS) patients with immunoglobulin gamma (IgG) oligoclonal bands (OCB) in the cerebrospinal fluid (CSF) have different genetic backgrounds and brain MRI features compared to those without. In this study, we aimed to determine whether CSF-OCB status is associated with long-term disability outcomes. We used Swedish MS register data on clinically definite MS patients with known OCB status. Date of birth, age at MS onset, and time to sustained Expanded Disability Status Scale (EDSS) milestones 3, 4, and 6; time to conversion to secondary progressive (SP) MS, sex, and immunomodulatory treatment (IMTs) duration were collected. Multivariate Cox regression models were used to investigate the association between OCB status and risk of reaching each milestone. The OCB-positive group reached disability milestones at an earlier time and younger age. OCB-positivity significantly increased the risk of reaching EDSS 3.0 (HR = 1.29, 95% CI 1.12 to 1.48, P < 0.001) and 4.0 (HR = 1.38, 95% CI 1.17 to 1.63, P < 0.001). The OCB-positive group had a 20% higher risk of conversion to SPMS. CSF-OCB presence is associated with higher risk of reaching EDSS milestones and conversion to SPMS. Our findings suggest higher disease modifying effect of OCB presence in the early inflammatory stages of MS., (© 2021. The Author(s).)

Background: The absence of reliable imaging or biological markers of phenotype transition in multiple sclerosis (MS) makes assignment of current phenotype status difficult., Objective: The authors sought to determine whether clinical information can be used to accurately assign current disease phenotypes., Methods: Data from the clinical visits of 14,387 MS patients in Sweden were collected. Classifying algorithms based on several demographic and clinical factors were examined. Results obtained from the best classifier when predicting neurologist recorded disease classification were replicated in an independent cohort from British Columbia and were compared to a previously published algorithm and clinical judgment of three neurologists., Results: A decision tree (the classifier) containing only most recently available expanded disability scale status score and age obtained 89.3% (95% confidence intervals (CIs): 88.8-89.8) classification accuracy, defined as concordance with the latest reported status. Validation in the independent cohort resulted in 82.0% (95% CI: 81.0-83.1) accuracy. A previously published classification algorithm with slight modifications achieved 77.8% (95% CI: 77.1-78.4) accuracy. With complete patient history of 100 patients, three neurologists obtained 84.3% accuracy compared with 85% for the classifier using the same data., Conclusion: The classifier can be used to standardize definitions of disease phenotype across different cohorts. Clinically, this model could assist neurologists by providing additional information.

Objective: To investigate the association between plasma neurofilament light chain (pNfL) levels and the risk of developing sustained disability worsening., Methods: Concentrations of pNfL were determined in 4,385 persons with multiple sclerosis (MS) and 1,026 randomly selected population-based sex- and age-matched controls using the highly sensitive Single Molecule Array (SimoaTM) NF-Light Advantage Kit. We assessed the impact of age-stratified pNfL levels above the 80th, 95th, and 99th percentiles among controls on the risk of Expanded Disability Status Scale (EDSS) worsening within the following year and reaching sustained EDSS scores of 3.0, 4.0, and 6.0 and conversion to secondary progressive multiple sclerosis (SPMS)., Results: The median (interquartile range [IQR]) pNfL was 7.5 (4.1) pg/mL in controls and 11.4 (9.6) pg/mL in MS ( p < 0.001). The median (IQR) duration of follow-up was 5 (5.1) years. High pNfL was associated with increased adjusted rates of EDSS worsening ranging between 1.4 (95% confidence intervals [CIs]: 1.1-1.8) and 1.7 (95% CI: 1.4-2.3). High pNfL was also associated with the risk of reaching a sustained EDSS score of 3.0, with adjusted rates ranging between 1.5 (95% CI: 1.2-1.8) and 1.55 (95% CI: 1.3-1.8) over all percentile cutoffs (all p < 0.001). Similar increases were observed for the risk of sustained EDSS score 4.0. In contrast, the risk of reaching sustained EDSS score 6.0 and conversion to SPMS was not consistently significant., Conclusions: Elevated pNfL levels at early stages of MS are associated with an increased risk of reaching sustained disability worsening. Hence, pNfL may serve as a prognostic tool to assess the risk of developing permanent disability in MS., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Patients with the 'aggressive' form of multiple sclerosis accrue disability at an accelerated rate, typically reaching Expanded Disability Status Score (EDSS) ≥ 6 within 10 years of symptom onset. Several clinicodemographic factors have been associated with aggressive multiple sclerosis, but less research has focused on clinical markers that are present in the first year of disease. The development of early predictive models of aggressive multiple sclerosis is essential to optimize treatment in this multiple sclerosis subtype. We evaluated whether patients who will develop aggressive multiple sclerosis can be identified based on early clinical markers. We then replicated this analysis in an independent cohort. Patient data were obtained from the MSBase observational study. Inclusion criteria were (i) first recorded disability score (EDSS) within 12 months of symptom onset; (ii) at least two recorded EDSS scores; and (iii) at least 10 years of observation time, based on time of last recorded EDSS score. Patients were classified as having 'aggressive multiple sclerosis' if all of the following criteria were met: (i) EDSS ≥ 6 reached within 10 years of symptom onset; (ii) EDSS ≥ 6 confirmed and sustained over ≥6 months; and (iii) EDSS ≥ 6 sustained until the end of follow-up. Clinical predictors included patient variables (sex, age at onset, baseline EDSS, disease duration at first visit) and recorded relapses in the first 12 months since disease onset (count, pyramidal signs, bowel-bladder symptoms, cerebellar signs, incomplete relapse recovery, steroid administration, hospitalization). Predictors were evaluated using Bayesian model averaging. Independent validation was performed using data from the Swedish Multiple Sclerosis Registry. Of the 2403 patients identified, 145 were classified as having aggressive multiple sclerosis (6%). Bayesian model averaging identified three statistical predictors: age > 35 at symptom onset, EDSS ≥ 3 in the first year, and the presence of pyramidal signs in the first year. This model significantly predicted aggressive multiple sclerosis [area under the curve (AUC) = 0.80, 95% confidence intervals (CIs): 0.75, 0.84, positive predictive value = 0.15, negative predictive value = 0.98]. The presence of all three signs was strongly predictive, with 32% of such patients meeting aggressive disease criteria. The absence of all three signs was associated with a 1.4% risk. Of the 556 eligible patients in the Swedish Multiple Sclerosis Registry cohort, 34 (6%) met criteria for aggressive multiple sclerosis. The combination of all three signs was also predictive in this cohort (AUC = 0.75, 95% CIs: 0.66, 0.84, positive predictive value = 0.15, negative predictive value = 0.97). Taken together, these findings suggest that older age at symptom onset, greater disability during the first year, and pyramidal signs in the first year are early indicators of aggressive multiple sclerosis., (© The Author(s) (2020). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To evaluate quality of life (QoL), measured by the EQ-5D, in adults with pediatric-onset multiple sclerosis (POMS) or adult-onset multiple sclerosis (AOMS) and explore determinants of QoL in both groups., Methods: Data were collected from the nationwide Swedish multiple sclerosis (MS) registry. Demographic characteristics, EQ-5D-3 level, Multiple Sclerosis Impact Scale (MSIS-29) score, Expanded Disability Status Scale (EDSS) score, Symbol Digit Modalities Test score, relapses, and disease-modifying therapy (DMT) exposure were collected on an approximately annual basis (2011-2019). Patients with definite MS with ≥2 EQ-5D measurements collected between ages 18 and 50 were included. The principal outcome was the EQ-5D visual analogue scale (EQ-VAS) score. Linear mixed models compared all available EQ-VAS scores between patients with POMS and patients with AOMS and determinants of EQ-VAS among patients with POMS and patients with AOMS (assessed separately)., Results: A total of 5,094 persons met inclusion criteria: 354 (6.9%) had POMS. A total of 21,357 unique EQ-5D scores were recorded. Most participants were female (70.0%) with a relapsing-onset disease course (98.1%). There was no difference in EQ-VAS scores between patients with POMS and patients with AOMS following adjustment for confounders (β-coefficient for patients with POMS vs patients with AOMS [reference]: 0.99; 95% confidence interval -0.89 to 2.87). Experiencing a relapse, severe neurologic disability (EDSS ≥6.0 vs <3.0), and higher MSIS-29 psychological score were consistently associated with lower QoL, while higher information processing efficiency and exposure to first-line DMTs were associated with higher QoL scores in both groups., Conclusions: There were no differences in QoL between patients with POMS and patients with AOMS in adulthood. Findings provide support for a focus on reducing neurologic disability and improving psychological status as approaches to potentially improve the QoL of persons with MS., (Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Blood Neurofilament light chain (NfL) has been suggested as a promising biomarker in several neurological conditions. Since blood NfL is the consequence of leaked NfL from the cerebrospinal fluid, differences in individuals' Body Mass Index (BMI) or blood volume (BV) might affect its correlation to other biomarkers and disease outcomes. Here, we investigated the correlation between plasma NfL, BMI, and BV in 662 controls and 2,586 multiple sclerosis cases. We found a significant negative correlation between plasma NfL, BMI/BV in both groups. Our results highlight the potential confounding effect of BMI/BV on associations between blood NfL and disease outcomes., (© 2019 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals, Inc on behalf of American Neurological Association.)

Objective: Depression is common in multiple sclerosis (MS), but its impact on disability worsening has not yet been determined. We explored the risk of disability worsening associated with depression in a nationwide longitudinal cohort., Methods: This retrospective cohort study used linked data from 3 Swedish nationwide registries: the MS Register, National Patient Register, and Prescribed Drug Register. Two incident cohorts were developed: cohort 1 included all registered cases of MS in the MS Registry (2001-2014) with depression defined as ≥1 ICD-10 code for depression; and cohort 2 comprised all cases of MS in the MS Registry (2005-2014) with depression defined as ≥1 prescription filled for an antidepressant. Cox regression models were used to compare the risk of reaching sustained disability milestone scores of 3.0, 4.0, and 6.0 on the Expanded Disability Status Scale (EDSS) between persons with MS with and without depression., Results: Cohort 1 included 5,875 cases; 502 (8.5%) had depression. Cohort 2 had 3,817 cases; 1,289 (33.8%) were prescribed an antidepressant. Persons with depression were at a significantly higher risk of reaching sustained EDSS scores of 3.0, 4.0, and 6.0, with hazard ratios of 1.50 (95% confidence interval [CI] 1.20-1.87), 1.79 (95% CI 1.40-2.29), and 1.89 (95% CI 1.38-2.57), respectively. A similar increased risk among persons exposed to antidepressants was observed, with hazard ratios of 1.37 (95% CI 1.18-1.60), 1.93 (95% CI 1.61-2.31), and 1.86 (95% CI 1.45-2.40) for sustained EDSS scores of 3.0, 4.0, and 6.0, respectively., Conclusion: Persons with MS and comorbid depression had a significantly increased risk of disability worsening. This finding highlights the need for early recognition and appropriate treatment of depression in persons with MS., (Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Background: Reductions of the peripapillary retinal nerve fiber layer (pRNFL) thickness has been indicated even in early-stages of multiple sclerosis (MS). The aim was to investigate the association between pRNFL thickness, measured with optical coherence tomography (OCT), and physical disability and cognitive impairment in MS., Methods: 465 MS patients and 168 healthy controls (HCs) were included. MS subjects were divided into subgroups according to disease subtype. All subjects underwent OCT examination of all pRNFL quadrants using Canon OCT-HS100. Associations were tested using linear mixed effect models. Physical disability was assessed with the Expanded Disability Status Scale (EDSS) and cognitive function with the Symbol Digit Modalities Test (SDMT)., Results: The average pRNFL, inferior pRNFL and temporal pRNFL thicknesses were significantly correlated to both EDSS (-1.0 µm, p < 0.01; -1.2 µm, p < 0.05; -1.2 µm, p < 0.01) and SDMT (0.1 µm, p < 0.05; 0.2 µm, p < 0.05; 0.2 µm, p < 0.01). A significant thickness loss compared with HCs was seen in the average pRNFL and in all quadrants except for the superior quadrant of primary progressive MS. The largest reduction compared with HCs was seen in the temporal pRNFL of PPMS eyes (-15.8 µm; p < 0.001)., Conclusion: The reduction of average pRNFL, inferior pRNFL and temporal pRNFL thickness is associated with physical and cognitive disability in MS. We suggest the use of temporal pRNFL as a more sensitive outcome as it showed the strongest association to both EDSS and SDMT., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: As the prevalence and incidence of Multiple Sclerosis (MS) are increasing remarkably in Iran, gathering standardized information regarding the individual's diagnosis, care, and outcomes through a uniform registry system would enable policy-makers to systematically plan for care quality improvements., Objective: To design a valid and reliable Persian version of a minimum data set to be utilized and integrated into the national MS registry system of Iran., Method: The minimum data set consisted of six domains including patient identification, family history of MS, diagnosis, disease course, disability status, and medications. The content validity was assessed based on 27 experts' opinions. Item-Content Validity Index (I-CVI) and Scale-Content Validity Index (S-CVI) were used to assess the questions and their validities. Reliability was evaluated using the intra-class correlation coefficient (ICC) of the test-retest results., Results: For validity appraisal, 27 experts reviewed the developed minimum data set. All the items had I-CVI values higher than the critical value of 0.78 in terms of relevance, clarity, and simplicity, except for "medication start date" and "medication end date" in relevance (I-CVI = 0.75 and 0.73, respectively) and "MS type" in simplicity (I-CVI = 0.76). The total S-CVI scores for relevance, clarity, and simplicity were higher than 0.9. In reliability assessment, 27 patients (out of 74 interviewed patients) were re-interviewed to assess the test-retest reliability. All ICCs were higher than the critical value of 0.7 (in 14 items out of 16), except for "progression to secondary-progressive MS" with the ICC = 0.68 and "the reason for medication discontinuance" with the ICC = 0.64., Conclusion: The use of standardized validated minimum data set has the potential to enable the researchers and policy-makers to systematically compare and analyze patient information. The Persian version of the minimum data set found to be valid and reliable in Iran., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: Benign multiple sclerosis (BMS) is often defined by the Expanded Disability Status Scale (EDSS) score of ≤3.0 after ≥15 years of disease duration. This classification's clinical relevance remains unclear as benign patients may suffer other impairments and advance towards a progressive course, prompting our objective to holistically investigate factors associated with BMS and its long-term prognosis., Methods: Benign cases were identified in the Swedish Multiple Sclerosis registry. Baseline clinical data, demographic features and influence of multiple sclerosis (MS) major risk alleles on likelihood of benign course were investigated. Physical disability (EDSS), cognitive function (Symbol Digit Modalities Test; SDMT) and self-reported and socioeconomic differences between benign and non-benign patients were evaluated using generalised estimation equations models., Results: 11222 patients (2420 benign/8802 non-benign) were included. Benign patients were more likely to be female and younger at MS onset, have fewer relapses within the first two and 5 years from onset and fully recover from the first relapse (p<0.001). No association between human leucocyte antigen ( HLA ) DRB1*15:01 carriership (OR: 0.97, 95% CI: 0.86 to 1.09) or HLA-A*02:01 lacking (OR: 0.99, 95% CI: 0.87 to 1.11) and benign/non-benign was found. Non-benign patients accumulated an extra 0.04 (95% CI 0.03 to 0.04, p<0.001) EDSS score/year, lost an extra 0.3 (95% CI - 0.39 to - 0.18, p<0.001) SDMT score/year and deteriorated faster in self-reported impact and socioeconomic measures (p<0.001)., Conclusion: Patients with BMS have a better disease course as they progress more slowly at the group level in all respects. Lack of an association with major genetic risk factors indicates that MS course is most likely influenced by either environmental factor(s) or genetic factors outside the HLA region., Competing Interests: Competing interests: LC, RM, AK, AM declare no conflict of interests. TO has received honoraria for lectures and advisory boards from Biogen, Novartis, Genzyme, Merck and TEVA. Unrestricted research grants from Biogen, Novartis and Genzyme. JH received honoraria for serving on advisory boards for Biogen, Sanofi-Genzyme and Novartis and speaker’s fees from Biogen, Merck-Serono, Bayer-Schering, Teva and Sanofi-Genzyme. He has served as P.I. for projects sponsored by, or received unrestricted research support from, Biogen, Merck-Serono, TEVA, Novartis, Sanofi-Genzyme and Bayer-Schering., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Multiple sclerosis (MS) treatment options have improved significantly over the past decades, but the consequences of MS can still be devastating and the needs for monitoring treatment surveillance are considerable. In the current study we used affinity proteomics technology to identify potential biomarkers which could ultimately be used to as facilitate treatment decisions. We profiled the intra-individual changes in the levels of 59 target proteins using an antibody suspension bead array in serial plasma samples from 44 MS patients during treatment with natalizumab followed by fingolimod. Nine proteins showed decreasing plasma levels during natalizumab treatment, with PEBP1 and RTN3 displaying the most significant changes. Protein levels remained stable during fingolimod treatment for both proteins. The decreasing PEBP1 levels during natalizumab treatment could be validated using ELISA and replicated in an independent cohort. These results support the use of this technology as a high throughput method of identifying potentially useful biomarkers of MS treatment., Competing Interests: Sahl Khalid Bedri, Anna Månberg, Carl Hamsten, Burcu Ayoglu, Ali Manouchehrinia, Peter Nilsson and Hans Grönlund have declared that no competing interests exist. Ola B. Nilsson is employed by TCER AB. Katharina Fink has received an unrestricted research grant from Biogen and travel compensations for holding lectures by Biogen, Teva, Roche and Novartis. Tomas Olsson received compensation for serving on scientific advisory boards or conducting lectures for Biogen and Genzyme, as well as unrestricted research grants from Biogen, Novartis, Genzyme, Almirall, and AstraZeneca. Jan Hillert received honoraria for serving on advisory boards for Biogen and Novartis and speaker’s fees from Biogen, Merck Serono, Bayer Schering, Teva and Sanofi Genzyme. He has served as P.I. for projects sponsored by, or received unrestricted research support from, Biogen, Sanofi Genzyme, Merck Serono, TEVA, Novartis and Bayer Schering. Anna Glaser has received unrestricted research support from Biogen. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Cigarette smoking is the most prominent significant cause of death and morbidity. It is recognised as a risk factor for a number of immune mediated, inflammatory diseases including multiple sclerosis (MS). Here, we review the complex immunological effects of smoking on the immune system, which include enhancement of inflammatory responses with a parallel reduction of some immune defences, resulting in an increased susceptibility to infection and a persistent proinflammatory environment. We discuss the effect of smoking on the susceptibility, clinical course, disability, and mortality in MS, the likely benefits of smoking cessation, and the specific immunological effects of smoking in MS. In conclusion, smoking is an important environmental risk factor for MS occurrence and outcome, and it acts in significant part through immunological mechanisms., (Copyright © 2018. Published by Elsevier B.V.)

Background: Persons who develop multiple sclerosis (MS) at a young age may bear a higher genetic risk load than persons who develop MS later in life; however, the contribution of familial influence to the risk of MS, in relation to onset age, has not been established., Objective: To investigate the familial risk of MS at two extremes of the spectrum of MS onset age: early onset (first MS symptom < 18 years of age) and late onset (first MS symptom ≥ 50 years)., Methods: Nationwide registries in Sweden were used to identify cases of MS and controls, and their familial relations. We estimated the odds ratio (OR) of an MS diagnosis for individuals with a relative diagnosed with early-onset or late-onset MS compared with those whose relatives did not have MS, using a nested case-control design., Results: 629 early-onset and 1148 late-onset MS patients were identified and matched to 10 controls from the general population by age and sex. The OR of MS for individuals with a first-degree relative diagnosed with early-onset MS was 10.86 (95% CI 6.87-17.17); and for late-onset MS was 8.08 (95% CI 6.12-10.67)., Conclusions: Our findings demonstrate no substantial differences in familial risk in persons with early- and late-onset MS.

Background: In multiple sclerosis (MS), various aspects of cognitive function can be detrimentally affected, thus patients' employment and social functioning is commonly impacted., Objective: To analyse income among MS patients in relation to cognitive function, assessed with the Symbol Digit Modalities Test (SDMT)., Methods: A cross-sectional study including 2080 MS patients was conducted linking national register-based data. Descriptive statistics and a two-part model were used to estimate differences in earnings and social benefits., Results: MS patients in the highest SDMT score quartile earned more than twice annually compared to patients in the lowest quartile, whereas patients in the lowest quartile received three times more income through social benefits. The difference in earnings and benefits across the SDMT performance quartiles remained statistically significant after adjusting for various clinical and socio-demographic variables, including physical disability. The corrected prevalence ratios for MS patients in the highest quartile for having income from earnings and benefits were 1.40 (95% confidence interval (CI): 1.29-1.49) and 0.81 (95% CI: 0.71-0.90), respectively, when compared to the patients in the lowest quartile., Conclusion: Cognitive function affects the financial situation of MS patients negatively and independently of physical disability. This warrants cognitive testing as a routine measure in health care services for MS patients.

Background: Rituximab is a chimeric monoclonal anti-CD20 B-cell-depleting antibody increasingly used off-label in multiple sclerosis (MS). The clinical relevance of anti-drug antibodies (ADAs) against rituximab in MS is unknown., Objective: To determine frequency of ADA in relation to B-cell counts, allergic reactions and clinical efficacy in a large cohort of MS-treated patients., Methods: Cross-sectional study with collection of serum samples from 339 MS patients immediately before a scheduled rituximab infusion. ADAs were detected using an in-house-validated electrochemiluminescent immunoassay and a commercial enzyme-linked immunosorbent assay (ELISA) to compare methods. Data on patient demographics and clinical outcomes were retrieved from the Swedish MS Registry and patient records., Results: ADAs were detected in 37% of relapsing-remitting MS and 26% in progressive forms of MS. Presence of ADAs decreased with increasing number of rituximab infusions. There was a significant association between both presence and titres of ADAs and incomplete B-cell depletion, but not with infusion/adverse reactions or clinical outcomes at the group level. Only five patients terminated rituximab during follow-up, four of which were ADA positive., Conclusion: Rituximab treatment is associated with a high degree of ADAs, which correlates with efficacy of B-cell depletion; however, the clinical relevance of ADAs remains uncertain.

Objectives: Multiple sclerosis (MS) is a chronic demyelinating disorder affecting young adults. Environmental factors and lifestyle behaviors are pivotal in MS pathophysiology. Smoking has been considered as an important risk factor in MS. Various recent studies have been conducted to measure the role of smoking on worsening disability in patients with MS, thus we intended to systematically assess effect of smoking on evolution of disability in this study., Materials & Methods: We queried MEDLINE, EMBASE and Cochrane Library with following keywords "Multiple Sclerosis, Smoking, Tobacco Use, Disability" on December 1st 2016. Original articles were included when smoking history was mentioned, disability was measured via expanded disability status scale (EDSS) or multiple sclerosis severity score (MSSS). Studies with insufficient outcome data, non-human, or in other languages than English were excluded., Results: Through literature review after duplicate removals, 268 articles were retrieved. A total of 56 articles were screened and 15 articles were assessed for eligibility, finally, eleven articles were included in this systematic review and meta-analysis. Ever smoking was significantly associated with increased EDSS (standardized mean difference (SMD) = 0.15, 95% CI = 0.01-0.28), but had no significant association with risk of reaching EDSS 4 (HR = 1.24, 95% CI = 0.89-1.72) or EDSS 6 (HR = 1.17, 95% CI = 0.88-1.57). Smoking had no effect on MSSS (SMD = 0.14, 95% CI = -0.04-0.32) or T2 lesion volume (SMD = 0.07, 95% CI = -0.08-0.22)., Conclusions: This meta-analysis showed smoking increased EDSS, insignificant findings were possibly due to the small number of studies, significant differences in methodologies, and variations in reporting of disability outcomes., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Previous research characterizing factors influencing multiple sclerosis (MS) disease progression has typically been based on time to disease milestones (Kaplan-Meier, Cox hazard regression, etc.). A limitation of these methods is the handling of the often large groups of patients not reaching the milestone., Objective: To characterize clinical factors influencing MS disease progression as annual transitions from each Expanded Disability Status Scale (EDSS)., Method: The annual progression of 11,964 patients from the Swedish MS Registry was analysed with 10 multinomial logistic regressions, that is, one for transition from each full EDSS with explanatory variables age, sex, age at onset, time in current EDSS, highest prior EDSS, MS course and treatment., Results: All factors (except sex) investigated had statistically significant impacts on transitions from at least one EDSS. However, significance and size of the effect are dependent on the EDSS state of the patient. Greater age, longer time in a state, highest prior EDSS, having progressive MS and treatment had significant impacts, whereas age at onset had minor impact., Conclusion: Our study confirms that established factors associated with MS disease worsening in time to disease milestones also have impacts on annual progression. This approach adds granularity to what EDSS these factors have an influence.

Background: Smoking is associated with a more severe disease course in people with multiple sclerosis (MS). The magnitude of effect of smoking cessation on MS progression is unknown. The aim of this study was to quantify the impact of smoking cessation on reaching MS disability milestones., Aims and Methods: This is a cross-sectional study with retrospective reports. A comprehensive smoking questionnaire was sent to 1270 patients with MS registered between 1994 and 2013 in the Nottingham University Hospital MS Clinics database. Demographic and clinical data were extracted from the clinical database. Cox proportional hazard regression was used to estimate effects of smoke-free years on the time to Expanded Disability Status Scale (EDSS) scores 4.0 and 6.0. MS Impact Scale 29 and Patient Determined Disease Steps were used to assess the physical and psychological impact of smoking., Results: Each "smoke-free year" was associated with 0.96 (95% confidence interval: 0.95 to 0.97) times decreased risk of reaching EDSS 4.0 and 0.97 (95% confidence interval: 0.95 to 0.98) times decreased risk of reaching EDSS 6.0. Nonsmokers showed a significantly lower level of disability in all the self-reported outcomes compared with current smokers., Conclusions: The reduction in the risk of disability progression after smoking cessation is significant and time dependent. The earlier the patients quit, the stronger the reduction in the risk of reaching disability milestones. The quantitative estimates of the impact of smoking cessation on reaching disability milestones in MS can be used in interventional trials., Implications: This study provides for the first time quantitative estimates of the effects of smoking cessation in MS, essential for informing smoking cessation trials. The clear effect of smoking cessation on MS progression suggests the need to consider adjusting for smoking cessation when assessing for treatment effects in clinical trials of treatments for MS. Smoking cessation should be an early intervention in people with MS.

Genetic variants within some cytokine receptor genes have been associated with MS susceptibility, including IL7RA and IL2RA. As these genes are expressed by cells targeted by immune-modulatory drugs, we explored the potential role of their gene products as biomarkers in monitoring MS treatment. We assessed the impact of natalizumab followed by fingolimod on the intra-individual changes of plasma protein levels of sIL-7Rα, sIL-2Rα and also sIL-6R and sgp130 in MS patients. During natalizumab treatment we observed a decline in sgp130 and sIL-7Rα levels, while subsequent fingolimod treatment lead to increased sgp130 and sIL-7Rα and decreased sIL-2Rα levels. In addition, during fingolimod treatment sIL-7Rα levels were increasing significantly more in patients homozygous for the MS risk genotype of rs6897932. We also observed an effect of the MS associated rs71624119 on sgp130 levels. These results may elucidate the pharmacodynamics of treatments and help identify biomarkers for MS outcomes., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Varicella zoster virus (VZV) infection has been implicated in multiple sclerosis (MS), but direct causal involvement has been disputed. Nevertheless, knowledge of VZV exposure is important, given the risk of serious complications of first exposure while undergoing immunosuppressive treatment, in particular with fingolimod. We distributed questionnaires to MS clinic patients, requesting information about history of chickenpox, sibling/household/occupational exposure, history of zoster (shingles), and disease-modifying treatment. A random, proportionally representative sample of 51 patients that included patients with positive, negative, and unknown chickenpox history were selected for determination of VZV IgG by ELISA. Of 1206 distributed questionnaires, 605 were returned (50% response rate). Of these, 86% reported history of chickenpox, 5.6% gave negative history, and 8.5% did not know. Of 594 who answered the zoster question, 78% gave a negative response, 4% did not know, and 104 (17%) answered yes. Of these, 83 reported 1 episode; 12 had 2; 5 had 3; and 1 each reported 5, 6, and 15 episodes. Of 51 patients tested for VZV IgG (44 "yes," 4 "no," and 3 "I don't know" answers to the question of whether they had chickenpox), 48 were seropositive; the 3 seronegative all had reported having had chickenpox. The high rate of MS patients reporting prior chickenpox infection is comparable with previous reports. A substantial proportion of MS patients, estimated to be higher than an age-matched general population, report single or multiple episodes of zoster. These data are useful for consideration of immunosuppressive treatments and/or VZV and zoster vaccination.

Background: The Multiple Sclerosis Severity Score (MSSS) is obtained by normalising the Expanded Disability Status Scale (EDSS) score for disease duration and has been a valuable tool in cross-sectional studies., Objective: To assess whether use of age rather than the inherently ambiguous disease duration was a feasible approach., Method: We pooled disability data from three population-based cohorts and developed an Age Related Multiple Sclerosis Severity (ARMSS) score by ranking EDSS scores based on the patient's age at the time of assessment. We established the power to detect a difference between groups afforded by the ARMSS score and assessed its relative consistency over time., Results: The study population included 26058 patients from Sweden ( n = 11846), Canada ( n = 6179) and the United Kingdom ( n = 8033). There was a moderate correlation between EDSS and disease duration ( r = 0.46, 95% confidence interval (CI): 0.45-0.47) and between EDSS and age ( r = 0.44, 95% CI: 0.43-0.45). The ARMSS scores showed comparable power to detect disability differences between groups to the updated and original MSSS., Conclusion: Since age is typically unbiased and readily obtained, and the ARMSS and MSSS were comparable, the ARMSS may provide a more versatile tool and could minimise study biases and loss of statistical power caused by inaccurate or missing onset dates.

Background: A subgroup of patients diagnosed with multiple sclerosis (MS) present with no oligoclonal bands (OCB) in the cerebrospinal fluid (CSF). Several studies report different clinical characteristics and genetic associations between the two groups., Objective: To investigate whether the OCB negative subgroup has a distinct etiology from band positive MS., Methods: Using nationwide registers to estimate familial risks, which reflect the genetic contribution of a disease., Results: Odds ratios of MS were similar for relatives to band positive and negative patients., Conclusion: From the perspective of familial liability, MS without OCB is etiologically closely related to the dominant subgroup of OCB positive MS.

Background: The course of multiple sclerosis (MS) has been studied in several cohorts; however, results have varied significantly., Objective: To describe the clinical course of MS in a nationwide cohort of patients., Method: Data from the Swedish MS register (SMSreg) were used to estimate the median time to the sustained Expanded Disability Status Scale (EDSS) scores 3.0, 4.0 and 6.0, onset of secondary progressive multiple sclerosis (SPMS) and death using Kaplan-Meier method. A possible effect of first-line treatments on age at EDSS 6.0 and SPMS was estimated., Results: In all, 12,703 patients were included. Median ages at EDSS scores 3.0, 4.0 and 6.0 were 55.4 (95% confidence interval (CI): 54.8-55.8), 60.7 (95% CI: 60.1-61.2) and 64.3 (95% CI: 63.6-64.7), respectively. Median age at SPMS was 57.4 (95% CI: 56.9-57.9). The median age at the time of death was 80.5 (95% CI: 79.9-81.1). Males and progressive-onset patients showed higher risks of disability worsening. On average, treated patients gained 1.6 years (95% CI: 0.2-3) to EDSS 6.0 as a result of treatment., Conclusion: Ages at disability milestones in this population-based cohort were higher than previously described in clinic- and regional-based samples. Nevertheless, MS patients die at younger age and live at an average almost 20 years with moderate and 30 years with severe disability.

Timely initiation of effective therapy is crucial for preventing disability in multiple sclerosis; however, treatment response varies greatly among patients. Comprehensive predictive models of individual treatment response are lacking. Our aims were: (i) to develop predictive algorithms for individual treatment response using demographic, clinical and paraclinical predictors in patients with multiple sclerosis; and (ii) to evaluate accuracy, and internal and external validity of these algorithms. This study evaluated 27 demographic, clinical and paraclinical predictors of individual response to seven disease-modifying therapies in MSBase, a large global cohort study. Treatment response was analysed separately for disability progression, disability regression, relapse frequency, conversion to secondary progressive disease, change in the cumulative disease burden, and the probability of treatment discontinuation. Multivariable survival and generalized linear models were used, together with the principal component analysis to reduce model dimensionality and prevent overparameterization. Accuracy of the individual prediction was tested and its internal validity was evaluated in a separate, non-overlapping cohort. External validity was evaluated in a geographically distinct cohort, the Swedish Multiple Sclerosis Registry. In the training cohort (n = 8513), the most prominent modifiers of treatment response comprised age, disease duration, disease course, previous relapse activity, disability, predominant relapse phenotype and previous therapy. Importantly, the magnitude and direction of the associations varied among therapies and disease outcomes. Higher probability of disability progression during treatment with injectable therapies was predominantly associated with a greater disability at treatment start and the previous therapy. For fingolimod, natalizumab or mitoxantrone, it was mainly associated with lower pretreatment relapse activity. The probability of disability regression was predominantly associated with pre-baseline disability, therapy and relapse activity. Relapse incidence was associated with pretreatment relapse activity, age and relapsing disease course, with the strength of these associations varying among therapies. Accuracy and internal validity (n = 1196) of the resulting predictive models was high (>80%) for relapse incidence during the first year and for disability outcomes, moderate for relapse incidence in Years 2-4 and for the change in the cumulative disease burden, and low for conversion to secondary progressive disease and treatment discontinuation. External validation showed similar results, demonstrating high external validity for disability and relapse outcomes, moderate external validity for cumulative disease burden and low external validity for conversion to secondary progressive disease and treatment discontinuation. We conclude that demographic, clinical and paraclinical information helps predict individual response to disease-modifying therapies at the time of their commencement., (© The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objectives: The aim of this study was to identify factors influencing the long-term clinical progression of multiple sclerosis (MS). A special objective was to investigate whether early treatment decisions influence outcome., Methods: We included 639 patients diagnosed with MS from 2001 to 2007. The median follow-up time was 99 months (8.25 years). Cox regression models were applied to identify factors correlating with the outcome variable defined as time from treatment start to irreversible score 4 of the Expanded Disability Status Scale (EDSS)., Results: Patients initiated on treatment later had a greater risk of reaching EDSS 4 (hazard ratio of 1.074 (95% confidence interval (CI), 1.048-1.101)), increased by 7.4% for every year of delay in treatment start after MS onset. Patients who started treatment after 3 years from MS onset reached the outcome sooner with hazard ratio of 2.64 (95% CI, 1.71-4.08) compared with the patients who started treatment within 1 year from MS onset. Baseline EDSS and age at onset were found to be predictive factors of disability progression., Conclusion: Early treatment initiation was associated with a better clinical outcome. In addition, we confirmed the well-established prognostic factors of late age at onset and early disability.

Background: Multiple sclerosis (MS) is a disease with profound heterogeneity in clinical course., Objective: To analyze sources and levels of income among MS patients in relation to disease phenotype with a special focus on identifying differences/similarities between primary progressive MS (PPMS) and secondary progressive MS (SPMS)., Methods: A total of 6890 MS patients aged 21-64 years and living in Sweden in 2010 were identified for this cross-sectional study. Descriptive statistics, logistic, truncated linear, and zero-inflated negative binomial regression models were used to estimate differences in income between SPMS, PPMS and relapsing-remitting MS (RRMS) patients., Results: RRMS patients earned almost twice as much as PPMS and SPMS patients (on average SEK 204,500, SEK 114,500, and SEK 79,800 in 2010, respectively). The difference in earnings between PPMS and SPMS was not statistically significant when analyzed with multivariable regression. The estimated odds ratio for PPMS patients to have income from earnings was not significantly different from SPMS patients (95% CI 0.98 to 1.59). PPMS and RRMS patients were less likely to receive benefits when compared to SPMS patients (by 6% and 27% lower, respectively)., Conclusion: Our findings argue for similarities between PPMS and SPMS and highlight the socioeconomic importance of preventing RRMS patients convert to SPMS., Competing Interests: Competing Interests: The authors have read the journal's policy and the authors of this manuscript have the following competing interests: Andrius Kavaliunas and Ali Manouchehrinia have declared that no competing interests exist. Virginija Danylaite Karrenbauer has received financial support from Stockholm County Council and Biogen´s Multiple Sclerosis Registries Research Fellowship Program. Hanna Gyllensten was funded from an unrestricted research grant from Biogen. Anna Glaser has received unrestricted research support from Biogen. Kristina Alexanderson has received unrestricted research grants from Biogen and from the Swedish Research Council for Working Life, Health and Welfare. Jan Hillert received honoraria for serving on advisory boards for Biogen and Novartis and speaker's fees from Biogen, MerckSerono, BayerSchering, Teva and SanofiGenzyme. He has served as P.I. for projects sponsored by, or received unrestricted research support from, Biogen, SanofiGenzyme, MerckSerono, TEVA, Novartis and BayerSchering. His MS research is funded by the Swedish Research Council and the Swedish Brain Foundation. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Objective: There are inconsistent data on mortality in people with multiple sclerosis (MS). We performed a meta-analysis of all-cause, cause-specific and gender-specific crude mortality rates (CMRs), and standardised mortality ratios (SMRs) in MS, and estimated the rate of change of CMR and SMR over the past 50 years., Methods: Medline, Embase and the Cochrane Library were searched., Keywords: 'Multiple Sclerosis' and ('standardised mortality' or 'standardized mortality')., Inclusion Criteria: availability of data on the number of deaths; mean or median patient follow-up or reports of SMRs; being a longitudinal study. 12 studies were included covering the period 1949-2012 (27 423 patients; 6628 deaths; 437 832 person-years follow-up). CMR was calculated. SMRs were extracted. CMRs and natural logarithm of SMRs were pooled by the method of the inverse of the variance. Meta-regression models were used to investigate the secular trends., Results: Pooled CMR was 9.78/1000 person-years (95% CI 6.81 to 14.02). Pooled all-cause SMR was 2.80 (95% CI 2.74 to 2.87). All-cause SMR was 2.56 (95% CI 2.47 to 2.66) in males and 3.06 (95% CI 2.97 to 3.17) in females. SMR due to cancer was 0.89 (95% CI 0.83 to 0.97). SMRs due to cardiovascular diseases, suicide, infection and respiratory diseases were 1.29 (95% CI 1.20 to 1.38), 2.13 (95% CI 1.80 to 2.51) and 2.91 (95% CI 2.60 to 3.26). There was no trend in CMRs, all-cause, and gender-specific SMRs., Conclusions: The excess mortality in MS relative to the general population has not changed over the past 50 years. Female patients with MS have higher survival disadvantage compared to that of males. Death due to cardiovascular diseases, suicide and infection is higher in patients with MS compared to the general population., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Importance: Smoking tobacco is a well-established risk factor for multiple sclerosis (MS), a chronic inflammatory disorder of the central nervous system usually characterized by bouts and remissions and typically followed by a secondary progressive (SP) course. However, it is not clear whether smoking after diagnosis is detrimental., Objective: To determine whether smoking after MS diagnosis is associated with a change in time to SP disease., Design, Setting, and Participants: Cross-sectional study of patients with prevalent MS who smoked at diagnosis (n = 728) taken from the Genes and Environment in Multiple Sclerosis Study, which consists of patients from the Swedish National MS Registry. The study entrance date was at time of first-year smoking. The study was conducted between November 2008 and December 2011, with patient environmental data collected from November 2009 to March 2011 via questionnaire. Study participants were from all counties in Sweden diagnosed as having MS at the time of the Genes and Environment in Multiple Sclerosis Study and registered in the Swedish National MS Registry. Patients with MS with relapsing-remitting disease course or SP were included. These patients' conditions were diagnosed according to the McDonald criteria and the patients responded to recruitment letters with detailed questionnaires., Exposure: Smoking, considered yearly after diagnosis and combined into a time-invariant covariate before diagnosis., Main Outcomes and Measures: Time to SPMS, measured using an accelerated failure time model, with smoking as a time-varying covariate. Other covariates included sex, age at diagnosis, snuff use, and smoking before diagnosis., Results: The optimized model illustrated that each additional year of smoking after diagnosis accelerated the time to conversion to SPMS by 4.7% (acceleration factor, 1.047; 95% CI, 1.023-1.072; P < .001). Kaplan-Meier plots demonstrated that those who continued to smoke continuously each year after diagnosis converted to SPMS faster than those who quit smoking, reaching SP disease at 48 and 56 years of age, respectively., Conclusions and Relevance: This study provides evidence that continued smoking is associated with an acceleration in time to SPMS and that those who quit fare better. Therefore, we propose that patients with MS should be advised to stop smoking once a diagnosis has been made, not only to lessen risks for comorbidities, but also to avoid aggravating MS-related disability.