Smoking worsens the prognosis in multiple sclerosis

Association of interleukin-17F (rs763780) single nucleotide polymorphism with multiple sclerosis and optic neuritis

IL-17F single nucleotide polymorphism (SNP) can affect IL-17F expression and activity and this can lead to the increased susceptibility to several autoimmune diseases. The aim was to investigate the association of IL-17F (rs763780) SNP with the development of multiple sclerosis (MS) in a cohort of Egyptian patients and to evaluate the effect of this polymorphism on the disease course. IL-17F (rs763780) gene polymorphisms was typed by TaqMan genotyping assay for 231 Egyptians divided into 102 MS patients and 129 healthy controls with matched age and sex. The IL-17F rs763780 C containing genotypes (CT+CC) and C allele have statistically significant increased frequency in MS patients when compared with controls (p = 0.005 and 0.004 respectively) especially in females' patients (p = 0.005 and 0.006 respectively). The heterozygous CT genotype was associated with the presence of optic neuritis (p = 0.038). The multivariable regression analysis revealed significant associations between smoking, the higher frequency of attacks and the prediction of higher EDSS score (p = 0.032, 0.049 respectively). It can be concluded that the IL-17F rs763780 C containing genotypes (CT and CC) and C allele may be risk factors for the development of MS in the studied Egyptian cohort by a gender-dependent mechanism that contributes to tendency for predisposition in females and optic neuritis is more common in patients carrying the CT heterozygous genotype.

The Effects of Nicotine and Cannabinoids on Cytokines

BACKGROUND

The usage of nicotine and cannabinoids has rapidly grown in popularity, leading to increased research into how they can affect people's health, both positively and negatively. Nicotine, Cannabidiol (CBD), and Δ9-tetrahydrocannabinol (THC) have been shown to have significant effects on cytokine function and inflammatory response.

OBJECTIVE

This study aimed to review and summarize the current literature on the effects of nicotine and cannabinoids on cytokines, including interleukins, TNF, IFN, and TGF-β.

METHODS

Literature search was conducted on Medline/PubMed electronic databases utilizing the search terms "nicotine" OR "cannabis" OR "cannabinoids" AND "cytokine" AND "inflammation" AND "stress" AND "immune" from 11/1973 to 02/2024.

RESULTS

THC and CBD usage have been associated with conflicting impacts on immune response, and observed to both exacerbate and inhibit inflammation. Nicotine has been shown to be generally proinflammatory with regards to cytokines. These responses have been reported to have significant effects on bodily response to inflammation-related diseases. Nicotine usage is associated with worsened outcomes for some conditions, like chronic pain, but improved outcomes for others, like arthritis. The impacts of cannabinoid usage tend to be more positive, exerting anti-inflammatory effects across a wide range of diseases. Given the widespread usage of these substances, it is important to understand the nature of their consequences on immune functions and the underlying mechanisms by which they act.

CONCLUSION

This review has covered how cannabinoids and nicotine affect inflammation directly and how these effects can be attributed to the treatment of inflammatory diseases. In summary, the existing research studying the effects of cannabinoids and nicotine supports the major relationship between nicotine and cannabis use and inflammatory diseases.

Predictors of Long-Term Visual Acuity in a Modern Cohort of Patients With Acute Idiopathic and Multiple Sclerosis-Associated Optic Neuritis

BACKGROUND

For patients with idiopathic or multiple sclerosis (MS)-associated optic neuritis (ON), the largest multicenter clinical trial (Optic Neuritis Treatment Trial [ONTT]) showed excellent visual outcomes and baseline high-contrast visual acuity (HCVA) was the only predictor of HCVA at 1 year. We aimed to evaluate predictors of long-term HCVA in a modern, real-world population of patients with ON and compare with previously published ONTT models.

METHODS

We performed a retrospective, longitudinal, observational study at the University of Michigan and the University of Calgary evaluating 135 episodes of idiopathic or MS-associated ON in 118 patients diagnosed by a neuro-ophthalmologist within 30 days of onset (January 2011-June 2021). Primary outcome measured was HCVA (Snellen equivalents) at 6-18 months. Multiple linear regression models of 107 episodes from 93 patients assessed the association between HCVA at 6-18 months and age, sex, race, pain, optic disc swelling, symptoms (days), viral illness prodrome, MS status, high-dose glucocorticoid treatment, and baseline HCVA.

RESULTS

Of the 135 acute episodes (109 Michigan and 26 Calgary), median age at presentation was 39 years (interquartile range [IQR], 31-49 years), 91 (67.4%) were women, 112 (83.0%) were non-Hispanic Caucasians, 101 (75.9%) had pain, 33 (24.4%) had disc edema, 8 (5.9%) had a viral prodrome, 66 (48.9%) had MS, and 62 (46.6%) were treated with glucocorticoids. The median (IQR) time between symptom onset and diagnosis was 6 days (range, 4-11 days). The median (IQR) HCVA at baseline and at 6-18 months were 20/50 (20/22, 20/200) and 20/20 (20/20, 20/27), respectively; 62 (45.9%) had better than 20/40 at baseline and 117 (86.7%) had better than 20/40 at 6-18 months. In linear regression models (n = 107 episodes in 93 patients with baseline HCVA better than CF), only baseline HCVA (β = 0.076; P = 0.027) was associated with long-term HCVA. Regression coefficients were similar and within the 95% confidence interval of coefficients from published ONTT models.

CONCLUSIONS

In a modern cohort of patients with idiopathic or MS-associated ON with baseline HCVA better than CF, long-term outcomes were good, and the only predictor was baseline HCVA. These findings were similar to prior analyses of ONTT data, and as a result, these are validated for use in conveying prognostic information about long-term HCVA outcomes.

Stroke risk in multiple sclerosis: a critical appraisal of the literature

Observational studies suggest that the occurrence of stroke on multiple sclerosis (MS) patients is higher compared to the general population. MS is a heterogeneous disease that involves an interplay of genetic, environmental and immune factors. The occurrence of stroke is subject to a wide range of both modifiable and non-modifiable, short- and long-term risk factors. Both MS and stroke share common risk factors. The immune mechanisms that underlie stroke are similar to neurodegenerative diseases and are attributed to neuroinflammation. The inflammation in autoimmune diseases may, therefore, predispose to an increased risk for stroke or potentiate the effect of conventional stroke risk factors. There are, however, additional determinants that contribute to a higher risk and incidence of stroke in MS. Due to the challenges that are associated with their differential diagnosis, the objective is to present an overview of the factors that may contribute to increased susceptibility or occurrence of stroke in MSpatients by performing a review of the available to date literature. As both MS and stroke can individually detrimentally affect the quality of life of afflicted patients, the identification of factors that contribute to an increased risk for stroke in MS is crucial for the prompt implementation of preventative therapeutic measures to limit the additive burden that stroke imposes.

The effects of different types of smoking on recovery from attack in hospitalized multiple sclerosis patients

BACKGROUND

Several studies demonstrated the association between tobacco smoking and higher risk and increased progression of multiple sclerosis (MS). Data about the effect of smoking during the recovery from MS attacks is limited. Furthermore, different types of tobacco exposures such as water pipe and passive smoking are not well assessed separately. So this study evaluated the effect of different types of smokes, cigarette and water pipe as well as passive smoking on the function recovery of relapsing-remitting MS (RRMS) attacks METHODS: This cohort study evaluated the adult patients with RRMS and Expanded Disability Status Scale (EDSS) < 5 in the attack phase. Patients were divided into two groups: smokers and non-smokers. The smokers included those who use cigarette, water pipe as well as passive smokers as subgroups for more analyses later. EDSS was monitored after relapse and two months after relapse. Change of EDSS considered as the criteria for functional recovery. The correlation between the amount of consumption and disability level was assessed among smokers by Pearson's correlation test. While, the difference of EDSS between smoker and non-smoker were assessed by Independent samples T-test.

RESULTS

142 patients were evaluated. 79 (55.6%) were smokers (43% male) while 63 (44.4%) were non-smokers (36.5% male). There was a statistically significant difference in change of EDSS between smoker and non-smoker groups, which change of EDSS was higher in non-smoker (-2.62 ± 0.90 non-smoker vs. -1.75 ± 0.76 smoker, P < 0.001). Also, only there was a significantly lesser decline in EDSS after two months in the cigarette smokers in subgroups analyses (P < 0.001). A correlation analysis revealed a significant positive correlation between the number per day of cigarette smoking and EDSS after relapse (r = 0.3, P = 0.03) and a significant positive correlation between minutes per month of smoking of water pipe and EDSS two months after relapse (r = ‎0.6‎‎, P > 0.001).

CONCLUSION

Tobacco smoking especially cigarette smoking is associated with a negative effect on recovery from the attack in patients with RRMS.

Characteristics of multiple sclerosis and demyelinating disease in an Asian American population

BACKGROUND

Race and ancestry influence the course of multiple sclerosis (MS).

OBJECTIVES

Explore clinical characteristics of MS and neuromyelitis optica spectrum disorder (NMOSD) in Asian American patients.

METHODS

Chart review was performed for 282 adults with demyelinating disease who self-identified as Asian at a single North American MS center. Demographics and clinical characteristics were compared to non-Asian MS patients and by region of Asian ancestry.

RESULTS

Region of ancestry was known for 181 patients. Most (94.7%) preferred English, but fewer East Asian patients did (80%, p = 0.0001). South Asian patients had higher neighborhood household income (p = 0.002). Diagnoses included MS (76.2%) and NMOSD (13.8%). More patients with NMOSD than MS were East and Southeast Asian (p = 0.004). For MS patients, optic nerve and spinal cord involvement were similar across regions of ancestry. Asian MS patients were younger at symptom onset and diagnosis than non-Asian MS patients. MS Severity Scale scores were similar to non-Asian MS patients but worse among Southeast Asians (p = 0.006).

CONCLUSIONS

MS severity was similar between Asian American patients and non-Asian patients. Region of ancestry was associated with differences in sociodemographics and MS severity. Further research is needed to uncover genetic, socioeconomic, or environmental factors causing these differences.

Environmental Influences on Risk and Disease Course in Pediatric Multiple Sclerosis

Pediatric multiple sclerosis (MS) accounts for 3%-10% of all patients diagnosed with MS. Complex interplay between environmental factors impacts the risk for MS and may also affect disease course. Many of these environmental factors are shared with adult-onset MS. However, children with MS are in closer temporal proximity to the biological onset of MS and have less confounding environmental exposures than their adult counterparts. Environmental factors that contribute to MS risk include: geographical latitude, viral exposures, obesity, vitamin deficiencies, smoking, air pollution, perinatal factors, gut microbiome, and diet. More recently, research efforts have shifted to studying the impact of these risk determinants on the clinical course of MS. In this article we will examine relevant environmental risk determinants of pediatric MS and review the current knowledge on how these factors may contribute to pediatric MS disease evolution.

Multiple Sclerosis in Mongolia; the First Study Exploring Predictors of Disability and Depression in Mongolian MS Patients

Mongolia is located at 45° north latitude in the center of the Asian continent, and about 80% of the territory is at 1000 m above sea level. Epidemiologically, multiple sclerosis (MS) has not been investigated in Mongolia, although there have been a few MS case reports. We investigated the characteristics of MS in Mongolia for the first time, focusing on the association between MS-related parameters and depression levels. We initiated cross-sectional analyses, using data from 27 MS patients aged 20 to 60 years in Ulaanbaatar, Mongolia. The patients completed a questionnaire on their lifestyles and clinical information. We classified the MS patients on the basis of disability levels using the expanded disability status scale (EDSS) scores: 11.1% mild disability and 88.9% moderate to severe disability (median EDSS score, 5.5). We also classified the patients on the basis of depression levels using the 9-item patient health questionnaire (PHQ-9) scores: 44.4% mild depression, 40.7% moderate depression, and 14.8% severe depression (mean PHQ-9's score, 9.96 ± 5.05). We used multivariate logistical regression analyses to identify predictors of EDSS or PHQ-9 scores. Disability levels were associated with vision and balance problems. Depression levels were associated with corticosteroid treatment; no patients were treated with disease-modifying drugs (DMDs). The odds ratios for disease onset age and treatment duration were associated with EDSS scores. In conclusion, MS onset age and treatment duration were independent predicting factors influencing the level of disability. Appropriate DMD treatment would lower the disability and depression levels.

Toward Precision Phenotyping of Multiple Sclerosis

The classification of multiple sclerosis (MS) has been established by Lublin in 1996 and revised in 2013. The revision includes clinically isolated syndrome, relapsing-remitting, primary progressive and secondary progressive MS, and has added activity (i.e., formation of white matter lesions or clinical relapses) as a qualifier. This allows for the distinction between active and nonactive progression, which has been shown to be of clinical importance. We propose that a logical extension of this classification is the incorporation of additional key pathological processes, such as chronic perilesional inflammation, neuroaxonal degeneration, and remyelination. This will distinguish MS phenotypes that may present as clinically identical but are driven by different combinations of pathological processes. A more precise description of MS phenotypes will improve prognostication and personalized care as well as clinical trial design. Thus, our proposal provides an expanded framework for conceptualizing MS and for guiding development of biomarkers for monitoring activity along the main pathological axes in MS.

Effects of cigarette smoke exposure on a mouse model of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory autoimmune disease associated with genetic and environmental factors. Cigarette smoking is harmful to health and may be one of the risk factors for MS. However, there have been no systematic investigations under controlled experimental conditions linking cigarette smoke (CS) and MS. The present study is the first inhalation study to correlate the pre-clinical and pathological manifestations affected by different doses of CS exposure in a mouse experimental autoimmune encephalomyelitis (EAE) model. Female C57BL/6 mice were whole-body exposed to either fresh air (sham) or three concentrations of CS from a reference cigarette (3R4F) for 2 weeks before and 4 weeks after EAE induction. The effects of exposure on body weight, clinical symptoms, spinal cord pathology, and serum biochemicals were then assessed. Exposure to low and medium concentrations of CS exacerbated the severity of symptoms and spinal cord pathology, while the high concentration had no effect relative to sham exposure in mice with EAE. Interestingly, the clinical chemistry parameters for metabolic profile as well as liver and renal function (e.g. triglycerides and creatinine levels, alkaline phosphatase activity) were lower in these mice than in naïve controls. Although the mouse EAE model does not fully recapitulate the pathology or symptoms of MS in humans, these findings largely corroborate previous epidemiological findings that exposure to CS can worsen the symptoms and pathology of MS. Furthermore, the study newly highlights the possible correlation of clinical chemistry findings such as metabolism and liver and renal function between MS patients and EAE mice.

Early predictors of conversion to secondary progressive multiple sclerosis

BACKGROUND

We conducted this study to estimated the time of conversion from relapsing-remitting MS (RRMS) to SPMS and its early predictor factors.

METHODS

In this retrospective study, demographic, clinical, and imaging data from MS patients at diagnosis were extracted. Cox proportional hazards model was used to assess the association between various baseline characteristics and conversion to SPMS. We also assessed the association brtween escalation and early intensive therapy approaches with transition to progressive phase.

RESULTS

Out of 1903 patients with RRMS at baseline, 293 (15.4%) patients progressed to SPMS during follow-up. The estimated number of patients converted to SPMS was 10% at 10-years, 50% at 20-years, and 93% at 30-years. On multivariate Cox regression analysis older age at onset (HR: 1.067, 95%CI: 1.048-1.085, p < 0.001), smoking (HR: 2.120, 95%CI: 1.203-3.736, p = 0.009), higher EDSS at onset (HR: 1.199, 95%CI: 1.109-1.295, p < 0.001), motor dysfunction (HR: 2.470, 95%CI: 1.605-3.800, p < 0.001), cerebellar dysfunction (HR: 3.096, 95%CI: 1.840-5.211, p < 0.001), and presence of lesions in spinal cord (HR: 0.573, 95%CI: 0.297-0.989, p = 0.042) increased the risk of conversion from RRMS to SPMS. No significant difference between escalation and EIT groups in the risk of transition to progressive phase (weighted HR = 1.438; 95% CI: 0.963, 2.147; p = 0.076) was found.

CONCLUSION

Our data support previous observations that smoking is a modifiable risk factor for secondary progressive MS and confirms that spinal cord involvement, age, and more severe disease at onset are prognostic factors for converting to secondary progressive MS.

Diagnosis and Treatment of Multiple Sclerosis: A Review

IMPORTANCE

Multiple sclerosis (MS) is an autoimmune-mediated neurodegenerative disease of the central nervous system characterized by inflammatory demyelination with axonal transection. MS affects an estimated 900 000 people in the US. MS typically presents in young adults (mean age of onset, 20-30 years) and can lead to physical disability, cognitive impairment, and decreased quality of life. This review summarizes current evidence regarding diagnosis and treatment of MS.

OBSERVATIONS

MS typically presents in young adults aged 20 to 30 years with unilateral optic neuritis, partial myelitis, sensory disturbances, or brainstem syndromes such as internuclear ophthalmoplegia developing over several days. The prevalence of MS worldwide ranges from 5 to 300 per 100 000 people and increases at higher latitudes. Overall life expectancy is less than in the general population (75.9 vs 83.4 years), and MS more commonly affects women (female to male sex distribution of nearly 3:1). Diagnosis is made based on a combination of signs and symptoms, radiographic findings (eg, magnetic resonance imaging [MRI] T2 lesions), and laboratory findings (eg, cerebrospinal fluid-specific oligoclonal bands), which are components of the 2017 McDonald Criteria. Nine classes of disease-modifying therapies (DMTs), with varying mechanisms of action and routes of administration, are available for relapsing-remitting MS, defined as relapses at onset with stable neurologic disability between episodes, and secondary progressive MS with activity, defined as steadily increasing neurologic disability following a relapsing course with evidence of ongoing inflammatory activity. These drugs include interferons, glatiramer acetate, teriflunomide, sphingosine 1-phosphate receptor modulators, fumarates, cladribine, and 3 types of monoclonal antibodies. One additional DMT, ocrelizumab, is approved for primary progressive MS. These DMTs reduce clinical relapses and MRI lesions (new T2 lesions, gadolinium-enhancing lesions). Efficacy rates of current DMTs, defined by reduction in annualized relapse rates compared with placebo or active comparators, range from 29%-68%. Adverse effects include infections, bradycardia, heart blocks, macular edema, infusion reactions, injection-site reactions, and secondary autoimmune adverse effects, such as autoimmune thyroid disease.

CONCLUSIONS AND RELEVANCE

MS is characterized by physical disability, cognitive impairment, and other symptoms that affect quality of life. Treatment with DMT can reduce the annual relapse rate by 29% to 68% compared with placebo or active comparator.

Little evidence for an effect of smoking on multiple sclerosis risk: A Mendelian Randomization study

The causes of multiple sclerosis (MS) remain unknown. Smoking has been associated with MS in observational studies and is often thought of as an environmental risk factor. We used two-sample Mendelian randomization (MR) to examine whether this association is causal using genetic variants identified in genome-wide association studies (GWASs) as associated with smoking. We assessed both smoking initiation and lifetime smoking behaviour (which captures smoking duration, heaviness, and cessation). There was very limited evidence for a meaningful effect of smoking on MS susceptibility as measured using summary statistics from the International Multiple Sclerosis Genetics Consortium (IMSGC) meta-analysis, including 14,802 cases and 26,703 controls. There was no clear evidence for an effect of smoking on the risk of developing MS (smoking initiation: odds ratio [OR] 1.03, 95% confidence interval [CI] 0.92-1.61; lifetime smoking: OR 1.10, 95% CI 0.87-1.40). These findings suggest that smoking does not have a detrimental consequence on MS susceptibility. Further work is needed to determine the causal effect of smoking on MS progression.

Role of Smoking in the Pathogenesis of Multiple Sclerosis: A Review Article

Multiple sclerosis (MS) is a complex and unpredictable neurological condition. It is the most commonly seen autoimmune disorder. The incidence of disease and its prevalence are growing worldwide. Early identification of the disease and accurate diagnosis is important to prevent further complications and disability. The etiology remains unclear, and it is believed that complex gene-environment interactions play an essential role. Genetic predisposition only describes a portion of the disease risk, whereas lifestyle and environmental factors are significant contributors. Smoking was identified as an important risk factor for MS. The main objectives of this review were to examine the underlying mechanisms of immune dysregulation in the development of MS, explore the association between smoking and MS, and identify other genetic and environmental factors that alter the risk of developing the disease. We searched PubMed for articles relevant to the study topic published between 2000 and 2020 using the search terms "multiple sclerosis," "cigarette smoking," "risk factors," and, "epigenetics." Studies reveal a marked association between smoking and the risk of MS. Unlike genetic risk factors, many lifestyles and environmental factors can be adjusted, with potential for prevention, particularly for people at the highest risk, such as families of individuals with MS.

Systematic review of prediction models in relapsing remitting multiple sclerosis

The natural history of relapsing remitting multiple sclerosis (RRMS) is variable and prediction of individual prognosis challenging. The inability to reliably predict prognosis at diagnosis has important implications for informed decision making especially in relation to disease modifying therapies. We conducted a systematic review in order to collate, describe and assess the methodological quality of published prediction models in RRMS. We searched Medline, Embase and Web of Science. Two reviewers independently screened abstracts and full text for eligibility and assessed risk of bias. Studies reporting development or validation of prediction models for RRMS in adults were included. Data collection was guided by the checklist for critical appraisal and data extraction for systematic reviews (CHARMS) and applicability and methodological quality assessment by the prediction model risk of bias assessment tool (PROBAST). 30 studies were included in the review. Applicability was assessed as high risk of concern in 27 studies. Risk of bias was assessed as high for all studies. The single most frequently included predictor was baseline EDSS (n = 11). T2 Lesion volume or number and brain atrophy were each retained in seven studies. Five studies included external validation and none included impact analysis. Although a number of prediction models for RRMS have been reported, most are at high risk of bias and lack external validation and impact analysis, restricting their application to routine clinical practice.

Vitamin D, smoking, EBV, and long-term cognitive performance in MS: 11-year follow-up of BENEFIT

OBJECTIVE

To investigate whether vitamin D, smoking, and anti-Epstein-Barr virus (EBV) antibody concentrations predict long-term cognitive status and neuroaxonal injury in multiple sclerosis (MS).

METHODS

This study was conducted among 278 patients with clinically isolated syndrome who participated in the clinical trial BENEFIT (Betaferon/Betaseron in Newly Emerging Multiple Sclerosis for Initial Treatment) and completed the 11-year assessment (BENEFIT-11). We measured serum 25-hydroxyvitamin-D (25(OH)D), cotinine (smoking biomarker), and anti-Epstein-Barr virus nuclear antigen 1 (EBNA-1) immunoglobulin G (IgG) at baseline and at months 6, 12, and 24 and examined whether these biomarkers contributed to predict Paced Auditory Serial Addition Test (PASAT)-3 scores and serum neurofilament light chain (NfL) concentrations at 11 years. Linear and logistic regression models were adjusted for sex, baseline age, treatment allocation, steroid treatment, multifocal symptoms, T2 lesions, and body mass index.

RESULTS

Higher vitamin D predicted better, whereas smoking predicted worse cognitive performance. A 50-nmol/L higher mean 25(OH)D in the first 2 years was related to 65% lower odds of poorer PASAT performance at year 11 (95% confidence intervals [95% CIs]: 0.14-0.89). Standardized PASAT scores were lower in smokers and heavy smokers than nonsmokers (p _trend = 0.026). Baseline anti-EBNA-1 IgG levels did not predict cognitive performance (p _trend = 0.88). Associations with NfL concentrations at year 11 corroborated these findings-a 50-nmol/L higher mean 25(OH)D in the first 2 years was associated with 20% lower NfL (95% CI: -36% to 0%), whereas smokers had 20% higher NfL levels than nonsmokers (95% CI: 2%-40%). Anti-EBNA-1 antibodies were not associated with NfL.

CONCLUSIONS

Lower vitamin D and smoking after clinical onset predicted worse long-term cognitive function and neuronal integrity in patients with MS.

The impact of modifiable risk factors on lesion burden in patients with early multiple sclerosis

INTRODUCTION

Some studies have indicated the importance of considering smoking, vitamin D deficiency and obesity as negative prognostic factors for clinical and MRI outcomes in multiple sclerosis (MS). This study aimed to evaluate the possible effects of these modifiable risk factors on brain MRI lesion burden of patients with early MS, also exploring the influence on initial clinical features.

METHODS

MS patients were enrolled at diagnosis time and examined for smoking, body mass index (BMI), serum level of lipids and 25(OH) vitamin D. Brain MRIs' were acquired and lesion volume assessed by Jim software. Clinical data (disease course, disease duration, and EDSS score) were also collected.

RESULTS

64 patients were enrolled, of these 4 (6.2%) had a primary progressive course. Mean age was 39.8 ± 11.1 years and mean EDSS 1.5 ± 1.1. Forty (62.5%) patients were smokers and 40 (62.5%) were overweight (BMI>25). Insufficient levels of vitamin D (<20 ng/mL) were reported in 36 (56.2%) patients, while 24 (37.5%) patients had an altered lipid profile with total cholesterol >200 mg/dl and LDL >100 mg/dl. No association between early clinical features and modifiable risk factors were reported. Multiple regression analysis showed an association between lesion burden and smoking status (p 0.003), while no association was reported with BMI, altered lipid profile and vitamin D insufficiency.

CONCLUSIONS

Several risk factors may play a role in evolution of MS. Our results show that smoking status, probably due to chronic vascular and neurotoxic effects of the cigarette components, can affect the brain damage from the early stages of MS. No association was observed with the other explored modifiable risk factors, although an effect due to the small sample size cannot be excluded.

RebiQoL: A randomized trial of telemedicine patient support program for health-related quality of life and adherence in people with MS treated with Rebif

RebiQoL was a phase IV multicenter randomized study to assess the impact of a telemedicine patient support program (MSP) on health-related quality of life (HRQoL) in patients with relapsing-remitting MS (RRMS) being administered with Rebif with the RebiSmart device. The primary endpoint was to assess the impact of MSP compared to patients only receiving technical support for RebiSmart on HRQoL at 12 months, using the psychological part of Multiple Sclerosis Impact Scale (MSIS-29), in patients administered with Rebif. A total of 97 patients diagnosed with RRMS were screened for participation in the study of which 3 patients did not fulfill the eligibility criteria and 1 patient withdrew consent. Of the 93 randomized patients, 46 were randomized to MSP and 47 to Technical support only. The demographic characteristics of the patients were well-balanced in the two arms. There were no statistical differences (linear mixed model) in any of the primary (difference of 0.48, 95% CI: -8.30–9.25, p = 0.91) or secondary outcomes (p>0.05). Although the study was slightly underpowered, there was a trend towards better adherence in the MSP group (OR 3.5, 95% CI 0.85–14.40, p = 0.08) although not statistically significant. No unexpected adverse events occurred. This study did not show a statistically significant effect of the particular form of teleintervention used in this study on HRQoL as compared to pure technical support, for MS patients already receiving Rebif with the RebiSmart device.

Trial Registration: ClinicalTrials.gov: NCT01791244.

Lifestyle and Environmental Factors in Multiple Sclerosis

Lifestyle and environmental factors potently influence the risk of multiple sclerosis (MS), because genetic predisposition only explains a fraction of the risk increase. There is strong evidence for associations of Epstein-Barr virus (EBV) infection, smoking, sun exposure/vitamin D, and adolescent obesity to risk of MS. There is also circumstantial evidence on organic solvents and shift work, all associate with greater risk, although certain factors like nicotine, alcohol, and a high coffee consumption associate with a reduced risk. Certain factors, smoking, EBV infection, and obesity interact with human leukocyte antigen (HLA) risk genes, arguing for a pathogenic pathway involving adaptive immunity. There is a potential for prevention, in particular for people at greater risk such as relatives of individuals with MS. All of the described factors for MS may influence adaptive and/or innate immunity, as has been argued for MS risk gene variants.

The Impact of Lifetime Alcohol and Cigarette Smoking Loads on Multiple Sclerosis Severity

Background: The association between lifestyle factors and Multiple Sclerosis (MS) disease severity and progression has been investigated to a lesser extent compared with susceptibility to the disease. Objective: We aimed to assess the impact of lifetime alcohol and cigarette smoking load on MS severity. Methods: Design: a cross-sectional study. Three hundred fifty-one patients consecutively admitted to the Department of Neurology were asked to complete the "Questionnaire of Lifestyle" (part of the European Prospective Investigation into Cancer and Nutrition project). An estimation of the cumulative lifetime cigarette smoking and alcohol load was calculated as the weighted sum of the mean number of cigarettes smoked and standard alcoholic drinks consumed per day at different ages. The measure of exposure was expressed in terms of pack-year and drink-year. Disease severity was estimated by the Multiple Sclerosis Severity Score (MSSS). Logistic regression analyses were performed using MSSS (first tertile vs. third tertile) as the outcome. Results: The median MSSS was higher (3.2 vs. 2.3, p = 0.002) in ever- vs. never-smokers, but we did not find a difference between ever- and never-drinkers (2.7 vs. 2.8, p = ns). Ever-smokers were almost twice as likely to fall in the upper MSSS tertile than never-smokers. Ever-drinkers did not show a statistically significant association between alcohol intake and MS severity. The risk of falling in the worst MSSS tertile for smokers was 10.81 (2.0-58.48; p < 0.01) if they were never-drinkers, whereas it was only 1.65 (0.89-3.03, p = 0.11) if they were also drinkers. On the other side, the risk of falling in the worst MSSS tertile for drinkers did not change as much, whether they also were smokers (0.46; 0.13-1.65; p = 0.23) or not (1.49; 0.55-4.04, p = 0.43). Conclusions: Cigarette smoking, unlike alcohol consumption, is associated with MS severity. Alcohol consumption may attenuate the effect of smoking on disease severity, acting as an effect modifier. The biological background of this effect is unknown. The limitations of our study are mostly due to its cross-sectional design.

Smoking and worsening disability in multiple sclerosis: A meta-analysis

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.

Association of Pre-Disease Body Mass Index With Multiple Sclerosis Prognosis

Both high body mass index (BMI) and smoking tobacco are known risk factors for developing multiple sclerosis (MS). However, it is unclear whether BMI, like smoking, is a risk factor for the secondary progressive (SP) course. We, therefore, sought to determine if high/low BMI at age 20 is associated to risk of SP development, in the context of smoking status. Using data from MS patients with BMI and smoking information available, we examined relapsing onset patients with MS onset after 20 years of age. Cox regressions were conducted on smokers and non-smokers, with BMI as the main exposure. In total, 5,598 relapsing onset MS patients were included. The models demonstrated that BMI > 30 was associated to increased risk of SPMS in smokers (hazard ratio 1.50, p = 0.036). This association of obesity at age 20 with increased risk of SP was not observed in non-smokers (hazard rate 0.97, p = 0.900). Since the risk is confined to smokers, the interaction observed may give insight to disease driving mechanisms.

Nicotine and autoimmunity: The lotus' flower in tobacco

Nicotine, the major component of cigarettes, has demonstrated conflicting impact on the immune system: some authors suggest that increases pro-inflammatory cytokines and provokes cellular apoptosis of neutrophils, releasing intracellular components that act as auto-antigens; others claimed that nicotine has a protective and anti-inflammatory effects, especially by binding to α7 subunit of nicotinic acetylcholine receptors. The cholinergic pathway contributes to an anti-inflammatory environment characterized by increasing T regulatory cells response, down-regulating of pro-inflammatory cytokines and a pro-inflammatory cells apoptosis. The effects of nicotine were studied in different autoimmune disease, as multiple sclerosis, type 1 diabetes, rheumatoid arthritis, sarcoidosis, Behçet's disease and inflammatory bowel diseases. The major problems about nicotine are the addiction and the adverse effects of related to each commercialized formulation. We sought in this review to summarize the knowledge accumulated to date concerning the relationship between nicotine and autoimmunity.

Smoking affects the interferon beta treatment response in multiple sclerosis

Objective

To investigate whether smoking in patients with relapsing-remitting multiple sclerosis (RRMS) treated with interferon beta (IFN-β) is associated with the relapse rate and whether there is an interaction between smoking and human leukocyte antigen (HLA)–DRB1*15:01, HLA-A*02:01, and the N-acetyltransferase-1 (NAT1) variant rs7388368A.

Methods

DNA from 834 IFN-β–treated patients with RRMS from the Danish Multiple Sclerosis Biobank was extracted for genotyping. Information about relapses from 2 years before the start of treatment to either the end of treatment or the last follow-up visit was obtained from the Danish Multiple Sclerosis Treatment Register. Smoking information came from a comprehensive questionnaire.

Results

We found that the relapse rate in patients with RRMS during IFN-β treatment was higher in smokers compared to nonsmokers, with an incidence rate ratio (IRR) of 1.20 (95% confidence interval [CI] 1.021–1.416, p = 0.027) and with an IRR increase of 27% per pack of cigarettes per day (IRR 1.27, 95% CI 1.056–1.537, p = 0.012). We found no association or interaction with HLA and the NAT1 variant.

Conclusion

In this observational cohort study, we found that smoking is associated with increased relapse activity in patients with RRMS treated with IFN-β, but we found no association or interaction with HLA or the NAT1 variant.

Smoking does not influence disability accumulation in primary progressive multiple sclerosis

BACKGROUND AND PURPOSE

The modifiable risk factor cigarette smoking has been associated with an increased risk of developing multiple sclerosis (MS) and with disease activity in relapsing-remitting MS. However, less is known about the effect of smoking on disease progression in progressive MS. Here the association between cigarette smoking and disability accumulation in primary progressive MS (PPMS) is investigated.

METHODS

Kaplan-Meier survival analyses and Cox proportional hazard modelling were used to investigate the influence of cigarette smoking on the risk of reaching Expanded Disability Status Scale (EDSS) 4 and 6 as well as the time from EDSS 4 to 6 in patients with PPMS.

RESULTS

In all, 416 patients with PPMS and available smoking history were identified. Median time to EDSS 4 was 4 years in ever-smokers and 5 years in never-smokers (P = 0.27), and it was 9 years to EDSS 6 in both ever-smokers and never-smokers (P = 0.48). Smokers were not at increased risk of faster progression to EDSS 4, 6 and from EDSS 4 to 6. Age at disease onset was the strongest risk factor for progression to EDSS 4, 6 and from EDSS 4 to 6.

CONCLUSIONS

Our investigation of a large and well-characterized population based PPMS cohort suggests that cigarette smoking does not influence disability accumulation in PPMS. Our findings support the idea that PPMS is driven by different underlying pathomechanisms than relapsing-remitting MS.

A systematic review of modifiable risk factors in the progression of multiple sclerosis

BACKGROUND

The presenting symptoms and rate of progression of multiple sclerosis (MS) are very heterogeneous. The diverse clinical manifestations and the clinical course of the disease may vary with modifiable risk factors.

OBJECTIVE

To systematically review modifiable risk factors and exposures associated with MS progression.

METHODS

We searched six databases till March 2015, reference-mined reviews, and consulted with experts (PROSPERO 2015:CRD42015016461). Two reviewers screened and extracted data. We used random meta-analysis models and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to assess the quality of evidence.

RESULTS

In total, 59 studies met inclusion criteria. Lower vitamin D levels were associated with higher Expanded Disability Status Scale (EDSS) scores ( r = -0.22; confidence interval (CI) = -0.32, -0.12; 11 studies; I² = 66%), smokers had an increased risk of MS progression (hazard ratio (HR) = 1.55; CI = 1.10, 2.19; I² = 72%; seven studies), and there was no association of MS progression with the use of epidural analgesics during childbirth delivery (three studies). There was insufficient evidence to draw conclusions for 11 risk factors due to conflicting results or use of different predictor and outcome measures.

CONCLUSION

MS progression was consistently associated with low vitamin D levels, and smoking was associated with a more rapid decline in MS disability. Studies used a variety of methods, predictors, and outcomes making it difficult to draw conclusions. Future studies should focus on prospective assessments.

Interactions between genetic, lifestyle and environmental risk factors for multiple sclerosis

Genetic predisposition to multiple sclerosis (MS) only explains a fraction of the disease risk; lifestyle and environmental factors are key contributors to the risk of MS. Importantly, these nongenetic factors can influence pathogenetic pathways, and some of them can be modified. Besides established MS-associated risk factors - high latitude, female sex, smoking, low vitamin D levels caused by insufficient sun exposure and/or dietary intake, and Epstein-Barr virus (EBV) infection - strong evidence now supports obesity during adolescence as a factor increasing MS risk. Organic solvents and shift work have also been reported to confer increased risk of the disease, whereas factors such as use of nicotine or alcohol, cytomegalovirus infection and a high coffee consumption are associated with a reduced risk. Certain factors - smoking, EBV infection and obesity - interact with HLA risk genes, pointing at a pathogenetic pathway involving adaptive immunity. All of the described risk factors for MS can influence adaptive and/or innate immunity, which is thought to be the main pathway modulated by MS risk alleles. Unlike genetic risk factors, many environmental and lifestyle factors can be modified, with potential for prevention, particularly for people at the greatest risk, such as relatives of individuals with MS. Here, we review recent data on environmental and lifestyle factors, with a focus on gene-environment interactions.

No association of tobacco use and disease activity in multiple sclerosis

Objective:

To study whether tobacco use is associated with MRI and clinical disease activity in patients with multiple sclerosis (MS).

Methods:

Prospective cohort study of 87 patients with relapsing-remitting MS originally included in a randomized placebo-controlled trial of omega-3 fatty acids in MS (the OFAMS Study). Serum levels of cotinine (biomarker of tobacco use) were analyzed at baseline and every 6 months for 2 years. MRI activity was assessed at baseline and monthly for 9 months and after 12 and 24 months.

Results:

Fifty-three patients (61%) had serum cotinine levels ≥85 nmol/L on ≥60% of the measurements and were considered tobacco users and 34 (39%) had cotinine levels <85 nmol/L, consistent with non–tobacco use. There was no association between tobacco use and the occurrence of new gadolinium-enhancing T1 lesions, new or enlarging T2 lesions, or their aggregate (combined unique activity). Furthermore, there was no association between cotinine levels and MRI activity for the tobacco users, and tobacco users did not have more relapses or Expanded Disability Status Scale progression.

Conclusion:

Our results indicate that tobacco use does not directly influence MRI activity or relapse rate in MS. This may implicate that the reported association between smoking and MS disease progression could be mediated through other mechanisms.

The Autoimmune Ecology

Autoimmune diseases (ADs) represent a heterogeneous group of disorders that affect specific target organs or multiple organ systems. These conditions share common immunopathogenic mechanisms (i.e., the autoimmune tautology), which explain the clinical similarities they have among them as well as their familial clustering (i.e., coaggregation). As part of the autoimmune tautology, the influence of environmental exposure on the risk of developing ADs is paramount (i.e., the autoimmune ecology). In fact, environment, more than genetics, shapes immune system. Autoimmune ecology is akin to exposome, that is all the exposures - internal and external - across the lifespan, interacting with hereditary factors (both genetics and epigenetics) to favor or protect against autoimmunity and its outcomes. Herein, we provide an overview of the autoimmune ecology, focusing on the immune response to environmental agents in general, and microbiota, cigarette smoking, alcohol and coffee consumption, socioeconomic status (SES), gender and sex hormones, vitamin D, organic solvents, and vaccines in particular. Inclusion of the autoimmune ecology in disease etiology and health will improve the way personalized medicine is currently conceived and applied.

Influence of cigarette smoking on white matter in patients with clinically isolated syndrome as detected by diffusion tensor imaging

PURPOSE

Cigarette smoking has been associated with increased occurrence of multiple sclerosis (MS), as well as clinical disability and disease progression in MS. We aimed to assess the effects of smoking on the white matter (WM) in patients with clinically isolated syndrome (CIS) using diffusion tensor imaging.

METHODS

Smoker patients with CIS (n=16), smoker healthy controls (n=13), nonsmoker patients with CIS (n=17) and nonsmoker healthy controls (n=14) were included. Thirteen regions-of-interest including nonenhancing T1 hypointense lesion and perilesional WM, and 11 normal-appearing white matter (NAWM) regions were drawn on color-coded fractional anisotropy (FA) maps. Lesion load was determined in terms of number and volume of WM hyperintensities.

RESULTS

A tendency towards greater lesion load was found in smoker patients. T1 hypointense lesions and perilesional WM had reduced FA and increased mean diffusivity to a similar degree in smoker and nonsmoker CIS patients. Compared with healthy smokers, smoker CIS patients had more extensive NAWM changes shown by increased mean diffusivity. There was no relationship between diffusion metrics and clinical disability scores, duration of the disease and degree of smoking exposure.

CONCLUSION

Smoker patients showed a tendency towards having greater number of WM lesions and displayed significantly more extensive NAWM abnormalities.

Risk factors associated with the onset of relapsing-remitting and primary progressive multiple sclerosis: a systematic review

Multiple sclerosis (MS) is a chronic central nervous system disease with a highly heterogeneous course. The aetiology of MS is not well understood but is likely a combination of both genetic and environmental factors. Approximately 85% of patients present with relapsing-remitting MS (RRMS), while 10–15% present with primary progressive MS (PPMS). PPMS is associated with an older onset age, a different sex ratio, and a considerably more rapid disease progression relative to RRMS. We systematically reviewed the literature to identify modifiable risk factors that may be associated with these different clinical courses. We performed a search of six databases and integrated twenty observational studies into a descriptive review. Exposure to Epstein-Barr virus (EBV) appeared to increase the risk of RRMS, but its association with PPMS was less clear. Other infections, such as human herpesvirus-6 and chlamydia pneumoniae, were not consistently associated with a specific disease course nor was cigarette smoking. Despite the vast literature examining risk factors for the development of MS, relatively few studies reported findings by disease course. This review exposes a gap in our understanding of the risk factors associated with the onset of PPMS, our current knowledge being predominated by relapsing-onset MS.

Tobacco smoking and excess mortality in multiple sclerosis: a cohort study

OBJECTIVE

As patients with multiple sclerosis (MS) have more than 2.5-fold increased mortality risk, we sought to investigate the impact of tobacco smoking on the risk of premature death and its contribution to the excess mortality in MS patients.

METHODS

We studied 1032 patients during the period 1994-2013 in a UK-based register. Cox regression model was used to investigate the impact of smoking on the risk of premature death, controlling for confounders. Smoking-specific mortality rates were compared with the UK general population.

RESULTS

Of 923 patients with clinically definite MS, 80 (46 males and 34 females) had died by December 2012. HRs for death in current smokers and ex-smokers relative to never smokers were 2.70 (95% CI 1.59 to 4.58, p<0.001) and 1.30 (95% CI 0.72 to 2.32; p = 0.37). The standardised mortality ratio, compared with the UK general population, when stratified by smoking status was 3.83 (95% CI 2.71 to 5.42) in current smokers, 1.96 (95% CI 1.27 to 3.0) in ex-smokers and 1.27 (95% CI 0.87 to 1.86) in non-smokers. Never smokers and ex-smokers with MS had similar mortality rates compared with never smokers and ex-smokers without MS in the male British doctors cohort (1.12 (95% CI 0.63 to 1.97) and 0.54 (95% CI 0.26 to 1.14), respectively), while current smokers with MS had 84% higher rate of death compared with current smokers without MS (95% CI 1.24 to 2.72).

CONCLUSIONS

Tobacco smoking can account for some of the excess mortality associated with MS and is a risk determinant for all-cause and MS-related death.

The experimental autoimmune encephalomyelitis disease course is modulated by nicotine and other cigarette smoke components

Epidemiological studies have reported that cigarette smoking increases the risk of developing multiple sclerosis (MS) and accelerates its progression. However, the molecular mechanisms underlying these effects remain unsettled. We have investigated here the effects of the nicotine and the non-nicotine components in cigarette smoke on MS using the experimental autoimmune encephalomyelitis (EAE) model, and have explored their underlying mechanism of action. Our results show that nicotine ameliorates the severity of EAE, as shown by reduced demyelination, increased body weight, and attenuated microglial activation. Nicotine administration after the development of EAE symptoms prevented further disease exacerbation, suggesting that it might be useful as an EAE/MS therapeutic. In contrast, the remaining components of cigarette smoke, delivered as cigarette smoke condensate (CSC), accelerated and increased adverse clinical symptoms during the early stages of EAE, and we identify a particular cigarette smoke compound, acrolein, as one of the potential mediators. We also show that the mechanisms underlying the opposing effects of nicotine and CSC on EAE are likely due to distinct effects on microglial viability, activation, and function.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Association between Smoking and Health Outcomes in Postmenopausal Women Living with Multiple Sclerosis

Background. In multiple sclerosis (MS), symptom management and improved health-related quality of life (HrQOL) may be modified by smoking. Objective. To evaluate the extent to which smoking is associated with worsened health outcomes and HrQOL for postmenopausal women with MS. Methods. We identified 251 Women's Health Initiative Observational Study participants with a self-reported MS diagnosis. Using a linear model, we estimated changes from baseline to 3 years for activities of daily living, total metabolic equivalent tasks (MET) hours per week, mental and physical component scales (MCS, PCS) of the SF-36, and menopausal symptoms adjusting for years since menopause and other confounders. Results. Nine percent were current and 50% past smokers. Age at smoking initiation was associated with significant changes in MCS during menopause. PCS scores were unchanged. While women who had ever smoked experienced an increase in physical activity during menopause, the physical activity levels of women who never smoked declined. Residual confounding may explain this finding. Smoking was not associated with change in menopausal symptoms during the 3-year follow-up. Conclusion. Smoking was not associated with health outcomes among post-menopausal women with MS.

Association between smoking and cognitive impairment in multiple sclerosis

PURPOSE

Although smoking is known to cause various symptoms in multiple sclerosis (MS) patients, there have been no reports regarding the relationship between smoking and cognitive impairment in MS. Studying the effects of cigarette smoking in MS patients is imperative as there is a high prevalence of cognitive impairment in MS patients. In this study we examined the potentially deleterious effects of heavy smoking on mentation of patients with MS.

PATIENTS AND METHODS

MS patients receiving care at the Neurology Clinic at Bezmialem Vakıf University, between the ages of 18-65 years who have at least graduated elementary school were included in the study. The Brief Repeatable Battery of Neuropsychological Tests (BRB-N) is a commonly used method to assess cognitive function in MS patients and was utilized in our study. Patients that smoked for at least 10 pack-years were considered heavy smokers.

RESULTS

ALL THE PATIENTS WERE STRATIFIED INTO TWO GROUPS: heavy smokers (n=20) and nonsmokers (n=24). For heavy smokers, their cognitive functioning was more impaired than that of nonsmokers (P=0.04, χ (2)=4.227). For patients with cognitive impairment, 78.9% of the Paced Auditory Serial Addition Test and 63.2% of the Symbol Digit Modalities Test scores were found to be lower.

CONCLUSION

Previous reports have suggested that smoking increases the frequency of relapse among individuals with relapsing-remitting MS and accelerates disease progression in patients with progressive MS. According to the results of our study, heavy smokers had increased cognitive impairment when compared to nonsmokers. Extensive studies are necessary to further elucidate the relationship between smoking and cognitive impairment in MS patients.

Tobacco smoking and disability progression in multiple sclerosis: United Kingdom cohort study

Tobacco smoking has been linked to an increased risk of multiple sclerosis. However, to date, results from the few studies on the impact of smoking on the progression of disability are conflicting. The aim of this study was to investigate the effects of smoking on disability progression and disease severity in a cohort of patients with clinically definite multiple sclerosis. We analysed data from 895 patients (270 male, 625 female), mean age 49 years with mean disease duration 17 years. Forty-nine per cent of the patients were regular smokers at the time of disease onset or at diagnosis (ever-smokers). Average disease severity as measured by multiple sclerosis severity score was greater in ever-smokers, by 0.68 (95% confidence interval: 0.36-1.01). The risk of reaching Expanded Disability Status Scale score milestones of 4 and 6 in ever-smokers compared to never-smokers was 1.34 (95% confidence interval: 1.12-1.60) and 1.25 (95% confidence interval: 1.02-1.51) respectively. Current smokers showed 1.64 (95% confidence interval: 1.33-2.02) and 1.49 (95% confidence interval: 1.18-1.86) times higher risk of reaching Expanded Disability Status Scale scores 4 and 6 compared with non-smokers. Ex-smokers who stopped smoking either before or after the onset of the disease had a significantly lower risk of reaching Expanded Disability Status Scale scores 4 (hazard ratio: 0.65, confidence interval: 0.50-0.83) and 6 (hazard ratio: 0.69, confidence interval: 0.53-0.90) than current smokers, and there was no significant difference between ex-smokers and non-smokers in terms of time to Expanded Disability Status Scale scores 4 or 6. Our data suggest that regular smoking is associated with more severe disease and faster disability progression. In addition, smoking cessation, whether before or after onset of the disease, is associated with a slower progression of disability.