1. |
- Beecham, Ashley H, et al.
(author)
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Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis.
- 2013
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In: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:11, s. 1353-60
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Journal article (peer-reviewed)abstract
- Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.
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2. |
- Bhan, Alok, et al.
(author)
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Neurofilament and Brain Atrophy and Their Association with Cognition in Multiple Sclerosis: A 10-Year Follow-Up Study
- 2023
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In: ACTA NEUROLOGICA SCANDINAVICA. - 0001-6314 .- 1600-0404. ; 2023
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Journal article (peer-reviewed)abstract
- Introduction. Cognitive impairment is an important contributor to disability in multiple sclerosis (MS). Disconnection of neuronal circuits due to axonal injury is probably an important underlying mechanism for this disability. Neurofilament light chain (NfL) is a neuron-specific constituent of axons and has gained increasing attention as a biomarker of axonal injury. Objective. To assess the association between NfL in serum (sNfL) and cerebrospinal fluid (cNfL) and cognitive function over 10 years and compare these associations with volumetric brain magnetic resonance imaging (MRI) measurements. Methods. Newly diagnosed MS patients were followed prospectively with baseline NfL and MRI as well as with clinical and cognitive assessments for up to 10 years. Results. Forty-one patients were included. Baseline sNfL correlated negatively with symbol digit modalities test (SDMT) at baseline (r=-0.45, p=0.005), year 5 (r=-0.41, p=0.017), and at year 10 (r=-0.52, p=0.008). Baseline cNfL correlated with baseline SDMT (r=-0.34, p=0.030) and SDMT at year 10 (r=-0.44, p=0.037). Baseline volumes of whole brain (r=0.476, p=0.002), gray matter (r=0.467, p=0.002), T1 (r=-0.627, p<0.001), and T2 lesion volumes (r=-0.475, p=0.002) correlated significantly with baseline SDMT. Longitudinal analyses showed that both MRI volumes and EDSS were associated with the rate of SDMT decline, whereas sNfL and cNfL were not. Conclusion. NfL levels measured in serum and cerebrospinal fluid were both associated with cognitive functioning in MS patients over a 10-year period from diagnosis. However, MRI volumes correlated strongly in addition to the rate of cognitive decline.
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3. |
- Biström, Martin, 1982-
(author)
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Environmental risk factors for the occurrence of multiple sclerosis
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Background. Multiple sclerosis (MS) is an inflammatory and degenerative disease of the central nervous system that typically debuts around age 30. About 2.3 million people are affected in the world today, and besides trauma it is the most common cause of neurological disability among young adults in the western world. The disease likely develops via a complex interplay of genetic vulnerability and environmental risk factors, and adolescence is assumed to be a critical time for disease initiation. The aim of this study was to investigate how MS risk in different age groups is influenced by vitamin D, infections with Epstein-Barr virus and Human herpesviruses 6A and B as well as the metabolic markers leptin and insulin.Methods. In this nested case-control study we identified pre-symptomatically drawn blood samples from individuals below age 40, that later developed relapsing remitting MS. This was done through crosslinking of the Swedish MS registry, or a local database, with six Swedish biobanks containing remainders of samples used in microbiological analyses. For each case, one control matched for biobank, sex, date of sampling and age of sampling was selected. These samples were then analysed to determine antibody reactivity against Epstein-Barr virus and Human herpesvirus 6A and B, as well as measure concentrations of leptin, insulin and 25-hydroxyvitamin D. The effect of these variables on MS risk was estimated using conditional logistic regression, both in the entire case-control material as well as stratified into three groups by age at sampling (<20, 20-29 and 30-39) and by sex.Results. Human herpesvirus 6A, but not B, was consistently associated with an increased risk of developing MS. In contrast, Epstein-Barr virus demonstrated an age dependent pattern indicating that early infection may be protective against MS while later infection increases the risk. As for the metabolic markers, insulin was not associated with MS while elevated levels of leptin showed an association with increased MS risk both among individuals below 20 years of age and among all men. For women there was instead an inverse association in the oldest group, aged 30-39, when adjusting the leptin analysis for insulin concentrations. Finally, having vitamin D concentrations in the top quintile was associated with decreased MS risk, without evidence of a stronger effect in young subjects.Conclusion. These results implicate Human herpesvirus 6A and leptin as risk factors for MS development. They also further support a protective role for vitamin D in MS etiology and provide serological evidence of an age dependency of Epstein-Barr virus infection as it relates to MS risk.
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4. |
- Bjørnevik, Kjetil, et al.
(author)
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Negative interaction between smoking and EBV in the risk of multiple sclerosis : The EnvIMS study
- 2017
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In: Multiple Sclerosis Journal. - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 23:7, s. 1018-1024
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Journal article (peer-reviewed)abstract
- BACKGROUND: Results from previous studies on a possible interaction between smoking and Epstein-Barr virus (EBV) in the risk of multiple sclerosis (MS) are conflicting.OBJECTIVES: To examine the interaction between smoking and infectious mononucleosis (IM) in the risk of MS.METHODS: Within the case-control study on Environmental Factors In Multiple Sclerosis (EnvIMS), 1904 MS patients and 3694 population-based frequency-matched healthy controls from Norway, Italy, and Sweden reported on prior exposure to smoking and history of IM. We examined the interaction between the two exposures on the additive and multiplicative scale.RESULTS: Smoking and IM were each found to be associated with an increased MS risk in all three countries, and there was a negative multiplicative interaction between the two exposures in each country separately as well as in the pooled analysis (p = 0.001). Among those who reported IM, there was no increased risk associated with smoking (odds ratio (OR): 0.95, 95% confidence interval (CI): 0.66-1.37). The direction of the estimated interactions on the additive scale was consistent with a negative interaction in all three countries (relative excess risk due to interaction (RERI): -0.98, 95% CI: -2.05-0.15, p = 0.09).CONCLUSION: Our findings indicate competing antagonism, where the two exposures compete to affect the outcome.
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5. |
- Bjørnevik, Kjetil, et al.
(author)
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Sun exposure and multiple sclerosis risk in Norway and Italy : The EnvIMS study
- 2014
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In: Multiple Sclerosis Journal. - : Sage Publications. - 1352-4585 .- 1477-0970. ; 20:8, s. 1042-1049
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Journal article (peer-reviewed)abstract
- OBJECTIVES:The objective of this paper is to estimate the association between multiple sclerosis (MS) and measures of sun exposure in specific age periods in Norway and Italy.METHODS:A total of 1660 MS patients and 3050 controls from Italy and Norway who participated in a multinational case-control study (EnvIMS) reported sun habits during childhood and adolescence.RESULTS:A significant association between infrequent summer outdoor activity and increased MS risk was found in Norway and in Italy. The association was strongest between the ages of 16 and 18 years in Norway (odds ratio (OR) 1.83, 95% confidence interval (CI) 1.30-2.59), and between birth and age 5 years in Italy (OR 1.56, 95% CI 1.16-2.10). In Italy a significant association was also found during winter (OR 1.42, 95% CI 1.03-1.97). Frequent sunscreen use between birth and the age of 6 years was associated with MS in Norway (OR 1.44, 95% CI 1.08-1.93) after adjusting for outdoor activity during the same period. Red hair (OR 1.67, 95% CI 1.06-2.63) and blonde hair (OR 1.36, 95% CI 1.09-1.70) were associated with MS after adjusting for outdoor activity and sunscreen use.CONCLUSION:Converging evidence from different measures underlines the beneficial effect of sun exposure on MS risk.
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6. |
- Burkill, Sarah, et al.
(author)
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The association between exposure to interferon-beta during pregnancy and birth measurements in offspring of women with multiple sclerosis
- 2019
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In: PLOS ONE. - : PLOS. - 1932-6203. ; 28:Suppl. 2, s. 371-372
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Journal article (peer-reviewed)abstract
- BACKGROUND: Interferon-beta (IFN-beta) is a commonly used treatment for multiple sclerosis (MS). Current guidelines recommend cessation of treatment during pregnancy, however the results of past studies on the safety of prenatal exposure to IFN-beta have been conflicting. A large scale study of a population of MS women is therefore warranted.OBJECTIVES: To assess whether, among those born to women with MS, infants prenatally exposed to IFN-beta show evidence of smaller size at birth relative to infants which were not prenatally exposed to any MS disease modifying drugs.METHODS: Swedish and Finnish register data was used. Births to women with MS in Sweden and Finland between 2005-2014 for which a birth measurement for weight, height, and head circumference was available were included. The exposure window was from 6 months prior to LMP to the end of pregnancy.RESULTS: In Sweden, 411 pregnancies were identified as exposed to IFN-beta during the exposure window, and 835 pregnancies were counted as unexposed to any MS DMD. The corresponding numbers for Finland were 232 and 331 respectively. Infants prenatally exposed to interferon-beta were on average 28 grams heavier (p = 0.17), 0.01 cm longer (p = 0.95), and had head circumferences 0.14 cm larger (p = 0.13) in Sweden. In Finland, infants were 50 grams lighter (p = 0.27), 0.02 cm shorter (p = 0.92) and had head circumferences 0.22 cm smaller (p = 0.15) relative to those unexposed.CONCLUSIONS: This study provides evidence that exposure to IFN-beta during pregnancy does not influence birth weight, length, or head circumference.
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7. |
- Hakkarainen, Katja Marja, et al.
(author)
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Pregnancy outcomes after exposure to interferon beta : a register-based cohort study among women with MS in Finland and Sweden
- 2020
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In: Therapeutic advances in neurological disorders. - : Sage Publications. - 1756-2856 .- 1756-2864. ; 13
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Journal article (peer-reviewed)abstract
- Background: Our aim was to estimate and compare the prevalence of adverse pregnancy outcomes among pregnant women with multiple sclerosis (MS) exposed to interferon beta (IFNB) and among women with MS unexposed to any MS disease-modifying drug (MSDMD).Methods: This cohort study used Finnish (1996-2014) and Swedish (2005-2014) national register data. Women with MS having IFNB dispensed 6 months before or during pregnancy as the only medication were considered as IFNB exposed (only IFNB-exposed), whereas women with MS unexposed to any MSDMD were considered unexposed (MSDMD-unexposed). Prevalence was described and compared using log-binomial or logistic regression and adjusted for potential confounders including maternal age and comorbidity.Results: Among 2831 pregnancies, 2.2% of the only IFNB-exposed and 4.0% of the MSDMD-unexposed women had serious adverse pregnancy outcomes [elective termination of pregnancy due to foetal anomaly (TOPFA), major congenital anomaly (MCA) in live, or stillbirth]. After adjustments, the prevalence of serious adverse pregnancy outcomes was lower among the only IFNB-exposed compared with the MSDMD-unexposed [relative risk 0.55, 95% confidence interval (CI) 0.31-0.96]. The prevalence of individual outcomes, including MCA, spontaneous abortions, and stillbirths was not increased with IFNB exposure. Women with MS exposed to IFNB appeared more likely to terminate their pregnancy for reasons other than foetal anomaly, compared with MSDMD-unexposed pregnant MS patients (odds ratio 1.71, 95% CI 1.06-2.78).Conclusion: In this large cohort study, no increase in the prevalence of adverse pregnancy outcomes was observed in women with MS exposed to IFNB compared with MS patients unexposed to any MSDMDs. This study together with other evidence led to a change in the labels of the IFNB products in September 2019 in the European Union, and IFNB use today may be considered during pregnancy, if clinically needed.
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8. |
- Lossius, Andreas, et al.
(author)
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Season of infectious mononucleosis and risk of multiple sclerosis at different latitudes; the EnvIMS Study
- 2014
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In: Multiple Sclerosis Journal. - : SAGE Publications (UK and US). - 1352-4585 .- 1477-0970. ; 20:6, s. 669-674
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Journal article (peer-reviewed)abstract
- Background: Seasonal fluctuations in solar radiation and vitamin D levels could modulate the immune response against Epstein-Barr virus (EBV) infection and influence the subsequent risk of multiple sclerosis (MS). Methods: Altogether 1660 MS patients and 3050 controls from Norway and Italy participating in the multinational case-control study of Environmental Factors In Multiple Sclerosis (EnvIMS) reported season of past infectious mononucleosis (IM). Results: IM was generally reported more frequently in Norway (p=0.002), but was associated with MS to a similar degree in Norway (odds ratio (OR) 2.12, 95% confidence interval (CI) 1.64-2.73) and Italy (OR 1.72, 95% CI 1.17-2.52). For all participants, there was a higher reported frequency of IM during spring compared to fall (pless than0.0005). Stratified by season of IM, the ORs for MS were 1.58 in spring (95% CI 1.08-2.31), 2.26 in summer (95% CI 1.46-3.51), 2.86 in fall (95% CI 1.69-4.85) and 2.30 in winter (95% CI 1.45-3.66). Conclusions: IM is associated with MS independently of season, and the association is not stronger for IM during spring, when vitamin D levels reach nadir. The distribution of IM may point towards a correlation with solar radiation or other factors with a similar latitudinal and seasonal variation.
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9. |
- Magalhaes, Sandra, et al.
(author)
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The EnvIMS Study: Design and Methodology of an International Case-Control Study of Environmental Risk Factors in Multiple Sclerosis
- 2015
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In: Neuroepidemiology. - : Karger. - 0251-5350 .- 1423-0208. ; 44:3, s. 173-181
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Journal article (peer-reviewed)abstract
- Background: Multiple sclerosis (MS) is a chronic disease of the central nervous system, often resulting in significant neurological disability. The causes of MS are not known; however, the incidence of MS is increasing, thereby suggesting that changes in lifestyle and/or environmental factors may be responsible. On this background, the Environmental Risk Factors in MS Study or EnvIMS study was designed to further explore the etiology of MS. The design and methodology are described, providing details to enable investigators to (i) use our experiences to design their own studies; (ii) take advantage of, and build on the methodological work completed for, the EnvIMS study; (iii) become aware of this data source that is available for use by the research community. Methods: EnvIMS is a multinational case-control study, enrolling 2,800 cases with MS and 5,012 population-based controls in Canada, Italy, Norway, Serbia and Sweden. The study was designed to investigate the most commonly implicated risk factors for MS etiology using a self-report questionnaire. Results/Conclusions:The use of a common methodology to study MS etiology across several countries enhances the comparability of results in different geographic regions and research settings, reduces the resources required for study design and enhances the opportunity for data harmonization.
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10. |
- Salzer, Jonatan, 1981-
(author)
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Environmental risk factors for multiple sclerosis
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Background Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. It usually strikes during young adulthood, and 2.5 million individuals are estimated to have the disease worldwide. The causes of MS are not known, but several factors have been shown to be associated with the risk of the disease, including certain genes, vitamin D, smoking and Epstein- Barr virus infection. Little is known about how/if these factors interact.Methods Study I: The risk of MS by month of birth was investigated using MS cases from the Swedish MS registry and using general population controls. Studies II–V: We identified MS cases who had donated blood prior to disease onset, and MS cases whose mothers had donated blood during pregnancy, by cross-linking a database of MS cases, and a database of mothers of MS cases, to two local biobank cohorts. One of them consisted of blood samples collected during early pregnancy, and one with samples collected during health controls. Levels of 25(OH)D (25-hydroxyvitamin D), RBP (retinol binding protein, a surrogate marker for vitamin A), CRP (C- reactive protein), cotinine (a nicotine metabolite) and anti Epstein-Barr virus nuclear antigen-1 (EBNA-1) antibodies were measured in cases and matched controls. The risk of MS by categories of these exposures was estimated in bi- and multivariable matched logistic regression models.Results Subjects born in spring had a higher risk of MS, but no influence of early gestational levels of the measured risk factors on the risk of MS in the offspring was observed. In prospective samples from MS cases and controls, 25(OH)D levels ≥75 nmol/l, intermediate RBP levels, and elevated CRP levels in young were associated with a decreased risk of MS. Elevated cotinine levels (suggestive of smoking) and high antibody reactivity against EBNA-1 were associated with an increased risk of MS. All factors but RBP were more clearly associated with MS in young subjects.Conclusion All factors analyzed in prospectively collected samples were associated with the risk of MS, and taken together, the data indicate that the key etiopathological events that lead to MS occur before the age of 20–30. Study II provides support for trials exploring the primary preventive potential of oral vitamin D supplementation.
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11. |
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12. |
- Sawcer, Stephen, et al.
(author)
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Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
- 2011
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 476:7359, s. 214-219
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Journal article (peer-reviewed)abstract
- Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.
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14. |
- Sorensen, Per Soelberg, et al.
(author)
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NORdic trial of oral Methylprednisolone as add-on therapy to Interferon beta-1a for treatment of relapsing-remitting Multiple Sclerosis (NORMIMS study) : a randomised, placebo-controlled trial
- 2009
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In: Lancet Neurology. - 1474-4422 .- 1474-4465. ; 8:6, s. 519-529
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Journal article (peer-reviewed)abstract
- BACKGROUND: Treatment of relapsing-remitting multiple sclerosis with interferon beta is only partly effective, and new more effective and safe strategies are needed. Our aim was to assess the efficacy of oral methylprednisolone as an add-on therapy to subcutaneous interferon beta-1a to reduce the yearly relapse rate in patients with relapsing-remitting multiple sclerosis. METHODS: NORMIMS (NORdic trial of oral Methylprednisolone as add-on therapy to Interferon beta-1a for treatment of relapsing-remitting Multiple Sclerosis) was a randomised, placebo-controlled trial done in 29 neurology departments in Denmark, Norway, Sweden, and Finland. We enrolled outpatients with relapsing-remitting multiple sclerosis who had had at least one relapse within the previous 12 months despite subcutaneous interferon beta-1a treatment (44 microg three times per week). We randomly allocated patients by computer to add-on therapy of either 200 mg methylprednisolone or matching placebo, both given orally on 5 consecutive days every 4 weeks for at least 96 weeks. The primary outcome measure was mean yearly relapse rate. Primary analyses were by intention to treat. This trial is registered, number ISRCTN16202527. FINDINGS: 66 patients were assigned to interferon beta and oral methylprednisolone and 64 were assigned to interferon beta and placebo. A high proportion of patients withdrew from the study before week 96 (26% [17 of 66] on methylprednisolone vs 17% [11 of 64] on placebo). The mean yearly relapse rate was 0.22 for methylprednisolone compared with 0.59 for placebo (62% reduction, 95% CI 39-77%; p<0.0001). Sleep disturbance and neurological and psychiatric symptoms were the most frequent adverse events recorded in the methylprednisolone group. Bone mineral density had not changed after 96 weeks. INTERPRETATION: Oral methylprednisolone given in pulses every 4 weeks as an add-on therapy to subcutaneous interferon beta-1a in patients with relapsing-remitting multiple sclerosis leads to a significant reduction in relapse rate. However, because of the small number of patients and the high dropout rate, these findings need to be corroborated in larger cohorts.
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15. |
- Wesnes, Kristin, et al.
(author)
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Body size and the risk of multiple sclerosis in Norway and Italy : The EnvIMS study.
- 2015
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In: Multiple Sclerosis Journal. - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 21:4, s. 388-395
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Journal article (peer-reviewed)abstract
- BACKGROUND: Obesity may be a risk factor for developing multiple sclerosis (MS).OBJECTIVE: We examined if body size influences the risk of MS in a population-based, case control study.METHODS: A total of 953 cases and 1717 controls from Norway and 707 cases and 1333 controls from Italy reported their body size by choosing a silhouette 1 to 9 (largest) every fifth year from age 5 to 30 and at time of study. The body size-related MS risk was defined by odds ratios (ORs) in logistic regression analyses adjusting for age, smoking and outdoor activity.RESULTS: In Norway a large body size (silhouettes 6-9) compared to silhouette 3 increased the risk of MS, especially at age 25 (OR 2.21; 95% CI 1.09-4.46 for men and OR 1.43; 95% CI 0.90-2.27 for women). When comparing silhouette 9 to 1, we found a significant dose-response from age 10 until age 30 peaking at age 25 (sex-adjusted OR 2.83; 95% CI 1.68-4.78). The association was present for at least 15 years prior to disease onset. No significant associations were found in Italy.CONCLUSIONS: Obesity from childhood until young adulthood is a likely risk factor for MS with a seemingly stronger effect in Norway than in Italy.
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16. |
- Wesnes, Kristin, et al.
(author)
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Physical Activity Is Associated With A Decreased Multiple Sclerosis Risk : The EnvIMS study
- 2018
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In: Multiple Sclerosis Journal. - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 24:2, s. 150-157
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Journal article (peer-reviewed)abstract
- Background: The lifestyle factors smoking and obesity have been associated with the risk of multiple sclerosis (MS). Physical activity (PA) may also be of importance.Objective: To examine the association between PA and MS risk in Italy, Norway, and Sweden and to evaluate the possible influence by established risk factors.Methods: In this case–control study, 1904 cases and 3694 controls were asked to report their average weekly amounts of light and vigorous PA during adolescence on a scale ranging from none to more than 3 hours activity. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) and adjusted for potential confounders.Results: Vigorous PA was inversely associated with MS risk in the pooled analysis (p-trend < 0.001) with an age- and sex-adjusted OR of 0.74 (95% CI: 0.63–0.87) when comparing the highest and lowest levels. Adjusting for outdoor activity, infectious mononucleosis, body size, and smoking yielded similar results. The association was present in all countries and was not affected by exclusion of patients with early disease onset. Light PA was not associated with the risk of MS.Conclusion: Our findings suggest that vigorous PA can modify the risk of developing MS independent of established risk factors.
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