A case-control study of the association between socio-demographic, lifestyle and medical history factors and multiple sclerosis

Multiple Sclerosis: New Insights into Molecular Pathogenesis and Novel Platforms for Disease Treatment

BACKGROUND

Multiple sclerosis (MS), a chronic inflammatory disorder, affects the central nervous system via myelin degradation. The cause of MS is not fully known, but during recent years, our knowledge has deepened significantly regarding the different aspects of MS, including etiology, molecular pathophysiology, diagnosis and therapeutic options. Myelin basic protein (MBP) is the main myelin protein that accounts for maintaining the stability of the myelin sheath. Recent evidence has revealed that MBP citrullination or deamination, which is catalyzed by Ca2+ dependent peptidyl arginine deiminase (PAD) enzyme leads to the reduction of positive charge, and subsequently proteolytic cleavage of MBP. The overexpression of PAD2 in the brains of MS patients plays an essential role in new epitope formation and progression of the autoimmune disorder. Some drugs have recently entered phase III clinical trials with promising efficacy and will probably obtain approval in the near future. As different therapeutic platforms develop, finding an optimal treatment for each individual patient will be more challenging.

AIMS

This review provides a comprehensive insight into MS with a focus on its pathogenesis and recent advances in diagnostic methods and its present and upcoming treatment modalities.

CONCLUSION

MS therapy alters quickly as research findings and therapeutic options surrounding MS expand. McDonald's guidelines have created different criteria for MS diagnosis. In recent years, ever-growing interest in the development of PAD inhibitors has led to the generation of many reversible and irreversible PAD inhibitors against the disease with satisfactory therapeutic outcomes.

Quantifying the Association between Objectively Measured Physical Activity and Multiple Sclerosis in the UK Biobank

INTRODUCTION

Objectively measured physical activity (PA) data were collected in the accelerometry substudy of the UK Biobank. UK Biobank also contains information about multiple sclerosis (MS) diagnosis at the time of and after PA collection. This study aimed to 1) quantify the difference in PA between prevalent MS cases and matched healthy controls, and 2) evaluate the predictive performance of objective PA measures for incident MS cases.

METHODS

The first analysis compared eight accelerometer-derived PA summaries between MS patients ( N = 316) and matched controls (30 controls for each MS case). The second analysis focused on predicting time to MS diagnosis among participants who were not diagnosed with MS. A total of 19 predictors including eight measures of objective PA were compared using Cox proportional hazards models (number of events = 47; 585,900 person-years of follow-up).

RESULTS

In the prevalent MS study, the difference between MS cases and matched controls was statistically significant for all PA summaries ( P < 0.001). In the incident MS study, the most predictive variable of progression to MS in univariate Cox regression models was lower age ( C = 0.604), and the most predictive PA variable was lower relative amplitude (RA, C = 0.594). A two-stage forward selection using Cox regression resulted in a model with concordance C = 0.693 and four predictors: age ( P = 0.015), stroke ( P = 0.009), Townsend deprivation index ( P = 0.874), and RA ( P = 0.004). A model including age, stroke, and RA had a concordance of C = 0.691.

CONCLUSIONS

Objective PA summaries were significantly different and consistent with lower activity among study participants who had MS at the time of the accelerometry study. Among individuals who did not have MS, younger age, stroke history, and lower RA were significantly associated with a higher risk of a future MS diagnosis.

The Importance of Managing Modifiable Comorbidities in People with Multiple Sclerosis: A Narrative Review

Multiple sclerosis (MS) is a chronic, inflammatory, degenerative demyelinating disease of the central nervous system (CNS) of unknown etiology that affects individuals in their early adulthood. In the last decade, life expectancy for people with MS (PwMS) has almost equaled that of the general population. This demographic shift necessitates a heightened awareness of comorbidities, especially the ones that can be prevented and modified, that can significantly impact disease progression and management. Vascular comorbidities are of particular interest as they are mostly modifiable health states, along with voluntary behaviors, such as smoking and alcohol consumption, commonly observed among individuals with MS. Vascular risk factors have also been implicated in the etiology of cerebral small vessel disease. Furthermore, differentiating between vascular and MS lesion load poses a significant challenge due to overlapping clinical and radiological features. This review describes the current evidence regarding the range of preventable and modifiable comorbidities and risk factors and their implications for PwMS.

A systematic review of Mendelian randomization studies on multiple sclerosis

Mendelian randomization (MR) is a powerful approach for assessing the causal effect of putative risk factors on an outcome, using genetic variants as instrumental variables. The methodology and application developed in the framework of MR have been dramatically improved, taking advantage of the many public genome-wide association study (GWAS) data. The availability of summary-level data allowed to perform numerous MR studies especially for complex diseases, pinpointing modifiable exposures causally related to increased or decreased disease risk. Multiple sclerosis (MS) is a complex multifactorial disease whose aetiology involves both genetic and non-genetic risk factors and their interplay. Previous observational studies have revealed associations between candidate modifiable exposures and MS risk; although being prone to confounding, and reverse causation, these studies were unable to draw causal conclusions. MR analysis addresses the limitations of observational studies and allows to establish reliable and accurate causal conclusions. Here, we systematically reviewed the studies evaluating the causal effect, through MR, of genetic and non-genetic exposures on MS risk. Among 107 papers found, only 42 were eligible for final evaluation and qualitative synthesis. We found that, above all, low vitamin D levels and high adult body mass index (BMI) appear to be uncontested risk factors for increased MS risk.

Physical activity and risk of multiple sclerosis: A Mendelian randomization study

Multiple evidence from epidemiological studies has suggested association between physical activity and risk of multiple sclerosis (MS). However, the conclusion was still controversial between studies, and whether the association was causal or confounded is elusive. To evaluate the role of physical activity with different intensities in the risk of MS, we first estimated their genetic correlation, and then conducted two-sample and multivariable Mendelian randomization analyses based on summary statistics from previous large genome-wide association studies. A significant genetic correlation was identified between moderate physical activity and the risk of MS (genetic correlation: -0.15, SE=0.05, P=2.9E-03). Meanwhile, higher moderate physical activity was significantly associated with a reduced risk of MS (OR:0.87, 95% CI:0.80-0.96, P=3.45E-03). Such association was further verified using summary statistics from another study on overall physical activity (OR:0.36, 95% CI:0.17-0.76, P=6.82E-03). The results were robust under all sensitivity analyses. Current results suggested moderate physical activity could reduce the risk of MS. These findings help better understand the role of physical activity in MS, and provide some lifestyle recommendations for individuals susceptible to MS.

Adherence to healthy dietary pattern is associated with lower risk of multiple sclerosis

Background

Different studies have confirmed the role of nutritional factors in the etiology of Multiple sclerosis (MS). However, dietary patterns associated with the risk of MS remain unknown.

Objectives

This study aimed to investigate the possible relationship between the existing dietary patterns and the risk of MS.

Methods

This case-control study was conducted in Mashhad city, Iran in 2015. In total, 197 MS patients and 200 control subjects (matched in terms of age, gender, education level, and body mass index) were enrolled in this study. The required data were collected through interviews and questionnaire completion. Moreover, the data on the usual dietary intake of each participant during the past year were evaluated using a valid and reliable semi-quantitative food frequency questionnaire (160 items). Logistic regression analysis was applied to discover the associations between dietary patterns and the risk of MS.

Results

Four major dietary patterns were identified in this study, including Unhealthy, Western, Healthy, and Traditional. After adjustment for smoking habits, the family history of autoimmune diseases and the duration of breastfeeding, the highest tertile of Healthy dietary pattern was found to be associated with the reduced risk of MS by 74% (OR = .26; P < .001), whereas the Unhealthy dietary pattern was associated with a three-fold increased risk of MS (OR = 3.04; P < .001). However, no correlation was observed between the Western and Traditional dietary patterns and the risk of MS.

Conclusion

According to the results of this study, a healthy diet may reduce the risk of MS, whereas an unhealthy dietary pattern may.

Physical exercise therapy for autoimmune neuroinflammation: Application of knowledge from animal models to patient care

Physical exercise (PE) impacts various autoimmune diseases. Accordingly, clinical trials demonstrated the safety of PE in multiple sclerosis (MS) patients and indicated beneficial outcomes. There is also an increasing body of research on the beneficial effects of exercise on experimental autoimmune encephalomyelitis (EAE), the animal model of MS, and various mechanisms underlying these effects were suggested. However, despite the documented favorable impact of PE on our health, we still lack a thorough understanding of its effects on autoimmune neuroinflammation and specific guidelines of PE therapy for MS patients are lacking. To that end, current findings on the impact of PE on autoimmune neuroinflammation, both in human MS and animal models are reviewed. The concept of personalized PE therapy for autoimmune neuroinflammation is discussed, and future research for providing biological rationale for clinical trials to pave the road for precise PE therapy in MS patients is described.

Applications of deep learning techniques for automated multiple sclerosis detection using magnetic resonance imaging: A review

Multiple Sclerosis (MS) is a type of brain disease which causes visual, sensory, and motor problems for people with a detrimental effect on the functioning of the nervous system. In order to diagnose MS, multiple screening methods have been proposed so far; among them, magnetic resonance imaging (MRI) has received considerable attention among physicians. MRI modalities provide physicians with fundamental information about the structure and function of the brain, which is crucial for the rapid diagnosis of MS lesions. Diagnosing MS using MRI is time-consuming, tedious, and prone to manual errors. Research on the implementation of computer aided diagnosis system (CADS) based on artificial intelligence (AI) to diagnose MS involves conventional machine learning and deep learning (DL) methods. In conventional machine learning, feature extraction, feature selection, and classification steps are carried out by using trial and error; on the contrary, these steps in DL are based on deep layers whose values are automatically learn. In this paper, a complete review of automated MS diagnosis methods performed using DL techniques with MRI neuroimaging modalities is provided. Initially, the steps involved in various CADS proposed using MRI modalities and DL techniques for MS diagnosis are investigated. The important preprocessing techniques employed in various works are analyzed. Most of the published papers on MS diagnosis using MRI modalities and DL are presented. The most significant challenges facing and future direction of automated diagnosis of MS using MRI modalities and DL techniques are also provided.

Childhood pet ownership and multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Many studies have been conducted investigating a range of environmental factors which have been implicated in the pathogenesis of multiple sclerosis (MS). We collated available data about exposure to domestic animals before symptom onset in MS to perform a systematic review and meta-analysis.

METHODS

Medline, Embase and Cinahl were searched for relevant articles, based on pre-defined inclusion and exclusion criteria and reference lists were hand-searched. Data were extracted and critical analysis was conducted using the Newcastle-Ottawa criteria. Meta-analysis used random effects.

RESULTS

Study heterogeneity was high and study quality was variable. Random effects meta-analysis showed no associations with any pet ownership and development of MS.

CONCLUSION

It is not possible to draw definitive conclusions from this work. The studies included had a high level of heterogeneity. There are many variables involved in pet ownership and exposure and the nature of the way these have been studied makes the analysis challenging.

Relationships between accelerometer-measured and multiple sclerosis: a 2-sample Mendelian randomization study

BACKGROUND

Observational studies suggest that physical activity (PA) can independently modify the risk of developing multiple sclerosis (MS).

OBJECTIVE

To investigate the causal effect of PA on MS by Mendelian randomization (MR) approaches.

METHODS

Through a genome-wide association study including 91,105 participants from UK Biobank, we obtained 5 single-nucleotide polymorphisms (SNPs) associated with accelerometer-measured PA (P < 5 × 10^-8). Summary-level data for MS were obtained from a meta-analysis, incorporating 14,802 subjects with MS and 26,703 healthy controls of European ancestry. MR analyses were performed using the inverse-variance-weighted method, weighted median estimator, and MR-PRESSO method. Additional analyses were further performed using MR-Egger intercept and Cochran's Q statistic to verify the robustness of our findings.

RESULTS

We failed to detect a causal effect of PA on MS (OR, 0.60; 95% confidence interval [CI], 0.30-1.20; P = 0.15) per in the random-effects IVW analysis. Additional MR methods yielded consistent results. MR-Egger regression suggested no evidence of horizontal pleiotropy (Intercept = 0.14, P = 0.21) and there seemed no substantial heterogeneity (I² = 29.8%, P = 0.22) among individual SNPs.

CONCLUSION

Our findings suggest that enhancing PA might not modify the risk of developing MS independent of established risk factors.

Early-life-trauma triggers interferon-β resistance and neurodegeneration in a multiple sclerosis model via downregulated β1-adrenergic signaling

Environmental triggers have important functions in multiple sclerosis (MS) susceptibility, phenotype, and trajectory. Exposure to early life trauma (ELT) has been associated with higher relapse rates in MS patients; however, the underlying mechanisms are not well-defined. Here we show ELT induces mechanistic and phenotypical alterations during experimental autoimmune encephalitis (EAE). ELT sustains downregulation of immune cell adrenergic receptors, which can be attributed to chronic norepinephrine circulation. ELT-subjected mice exhibit interferon-β resistance and neurodegeneration driven by lymphotoxin and CXCR2 involvement. These phenotypic changes are observed in control EAE mice treated with β1 adrenergic receptor antagonist. Conversely, β1 adrenergic receptor agonist treatment to ELT mice abrogates phenotype changes via restoration of immune cell β1 adrenergic receptor function. Our results indicate that ELT alters EAE phenotype via downregulation of β1 adrenergic signaling in immune cells. These results have implications for the effect of environmental factors in provoking disease heterogeneity and might enable prediction of long-term outcomes in MS.

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.

A systematic review of morbidities suggestive of the multiple sclerosis prodrome

INTRODUCTION

The identification of a prodromal phase in multiple sclerosis (MS) could have major implications for earlier recognition and management of MS. The authors conducted a systematic review assessing studies of morbidities before, or at, MS onset or diagnosis.Areas covered: Two independent reviewers searched Medline, Embase, Psycinfo and CINAHL from inception to February 8^th, 2019. To be eligible, studies had to be published in English and report the relative occurrence of at least one morbidity or symptom before, or at, MS onset or diagnosis among MS cases in comparison to a control group not known to have MS. Findings were narratively synthesized. Study quality was assessed using the Newcastle-Ottawa scale (NOS, maximum score 9).Expert opinion: Twenty-nine studies were included, which comprised 83,590 MS cases and 396,343 controls. Most were case-control studies (25/29), 8/29 were of high quality (NOS≥8) and 19/29 examined the period before MS symptom onset. Most studies assessing anxiety, depression, migraine and lower cognitive performance found these conditions to be more prevalent before MS onset or diagnosis relative to controls. There was limited evidence to implicate other conditions. Thus, there is evidence that anxiety, depression, migraine and lower cognitive performance form part of the MS prodrome.

Towards a comprehensive etiopathogenetic and pathophysiological theory of multiple sclerosis

Background: Multiple sclerosis (MS) is a neurodegenerative disease caused by dysfunction of the immune system that affects the central nervous system (CNS). It is characterized by demyelination, chronic inflammation, neuronal and oligodendrocyte loss and reactive astrogliosis. It can result in physical disability and acute neurological and cognitive problems. Despite the gains in knowledge of immunology, cell biology, and genetics in the last five decades, the ultimate etiology or specific elements that trigger MS remain unknown. The objective of this review is to propose a theoretical basis for MS etiopathogenesis.Methods: Search was done by accessing PubMed/Medline, EBSCO, and PsycINFO databases. The search string used was "(multiple sclerosis* OR EAE) AND (pathophysiology* OR etiopathogenesis)". The electronic databases were searched for titles or abstracts containing these terms in all published articles between January 1, 1960, and June 30, 2019. The search was filtered down to 362 articles which were included in this review.Results: A framework to better understand the etiopathogenesis and pathophysiology of MS can be derived from four essential factors; mitochondria dysfunction (MtD) & oxidative stress (OS), vitamin D (VD), sex hormones and thyroid hormones. These factors play a direct role in MS etiopathogenesis and have a modulatory effect on many other factors involved in the disease.Conclusions: For better MS prevention and treatment outcomes, efforts should be geared towards treating thyroid problems, sex hormone alterations, VD deficiency, sleep problems and melatonin alterations. MS patients should be encouraged to engage in activities that boost total antioxidant capacity (TAC) including diet and regular exercise and discouraged from activities that promote OS including smoking and alcohol consumption.

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.

Intracerebral Hemorrhage in Multiple Sclerosis: A Retrospective Cohort Study

BACKGROUND

To identify the vascular risk factors associated with the occurrence of intracerebral hemorrhage (ICH) in Multiple Sclerosis (MS) patients.

METHODS

This is an observational, retrospective cohort study using the nationwide electronic medical records (EMR) database. Patients with the diagnosis of MS were extracted from inpatient and outpatient EMR using the international classification of diseases, ninth/tenth revisions, clinical modification codes. We excluded patients younger than 18 years, and those where gender was not specified. Patients were further stratified based on their demographics, risk factors, medications, and comorbidities. Tobacco, diabetes, hypertension, and alcohol were the predicting variables; antiplatelet medication, and anticoagulant agents were the primary exposures for the development of ICH. A validated diagnosis code algorithm defined the diagnosis of ICH. Multivariable logistic regression models were utilized to assess the risk of ICH in MS patients.

RESULTS

Of the total 57,099 MS patients (women: 75%, n = 41,517), 107 (.19%) sustained an ICH. Age (OR = 2.74, CI = 1.13-6.62), use of anticoagulants (OR = 2.15, 95% CI = 1.30-3.56, P = .0028), and history of tobacco exposure (OR = 2.44, CI = 1.37-4.36, P = .0025) were associated with increased risk of ICH. Use of antiplatelet and disease-modifying drugs (DMDs) showed a protective trend against ICH.

CONCLUSIONS

Tobacco exposure and anticoagulant use were strongly associated with increased risk of ICH in patients with MS. There might be a protective effect that antiplatelet and DMDs have in the pathophysiology of this disease. Further prospective investigations are warranted to establish these associations.

Effect of smoking on multiple sclerosis: a meta-analysis

Background

Despite our awareness of the significant effect of smoking on multiple sclerosis (MS), there was a serious lack of information about the effect of different types of smoking habit on MS as well as the dose-response relationship between smoking and MS, but this gap was addressed by this meta-analysis.

Methods

Major electronic databases, including PubMed, Web of Science and Scopus were searched until July 2015. Epidemiological studies addressing the association between smoking and MS were enrolled. The heterogeneity across studies was investigated by Q-test and I2 statistic. The probability of publication bias was explored using Begg's and Egger's tests. The results were expressed as odds ratio (OR) with 95% confidence intervals (CI) using a random effects model.

Results

We identified a total of 10 687 references and included 34 studies involving 623 852 participants. Compared with nonsmokers, the OR estimate of MS was 1.46 (1.33, 1.59) among ever smokers, 1.57 (1.34, 1.80) among current smokers, 1.36 (1.27, 1.46) among ex-smokers and 1.12 (0.87, 1.36) among passive smokers. In addition, analyzing the effect of cigarette pack-year on MS indicated that the OR estimate of MS was 1.34 (1.06, 1.61) for 1-5 cigarette pack-years, 1.56 (1.15, 1.97) for 6-10 cigarette pack-years, 1.74 (1.16, 2.33) for 11-15 cigarette pack-years and 1.46 (0.49, 2.43) for more than 15 cigarette pack-years.

Conclusions

Smoking habits are significantly associated with MS, although the association is not very strong. However, there is a dose-response relationship between the smoking habits and MS.

Lifestyle factors and multiple sclerosis: A population-based incident case-control study

OBJECTIVE

Although low sun exposure, low vitamin D, and smoking are established risk factor of multiple sclerosis (MS), there is less evidence on the role of the other lifestyle factors. We examined the association of sun exposure, physical activity, drug abuse, and alcohol intake with MS.

MATERIALS AND METHODS

This was population-based incident case-control study in Iran with 547 incident cases and 1057 general population controls (7/8/2013-17/2/2015). Logistic regression was used to analyse the data.

RESULTS

Higher sun exposure during adolescence was associated with a reduced risk of MS, both in summer (test for trend p < 0.001) and winter (P < 0.001), while physical activity was not associated with MS (test for trend p = 0.712). Lifetime drug abuse (OR for ever use 2.93 (1.83-4.70)), with a dose-response association (test for trend p < 0.001), and alcohol intake (OR for ever use 1.49 (1.05-2.12)) was significantly associated with an increased risk of MS.

CONCLUSION

In a middle-eastern setting, we found that sun exposure during adolescence, drug abuse, and alcohol use were all associated with MS. Increasing sun exposure and reducing drug abuse and the use of alcohol through educational programs is likely to reduce the rate of MS.

Smoking under hypoxic conditions: a potent environmental risk factor for inflammatory and autoimmune diseases

Autoimmune disease management presents a significant challenge to medical science. Environmental factors potentially increase the risk of developing inflammatory and autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis, and lupus. Among various environmental stresses, cigarette smoke and hypoxia have both been reported to lead to an enhanced risk of inflammatory and autoimmune diseases.In this review, we shed light on all reported mechanisms whereby cigarette smoke and a hypoxic environment can induce inflammatory and autoimmune diseases and discuss how hypoxic conditions influence the cigarette smoke-induced threat of inflammatory and autoimmune disease development.Cigarette smoke and hypoxia both lead to increased oxidative stress and production of reactive oxygen species and other free radicals, which have various effects including the generation of autoreactive pro-inflammatory T cells and autoantibodies, reductions in T regulatory (Treg) cell activity, and enhanced expression of pro-inflammatory mediators [e.g., interleukin-6 (IL-6), interleukin-4 (IL-4) and interleukin-8 (IL-8)]. Accordingly, smoking and hypoxic environments may synergistically act as potent environmental risk factors for inflammatory and autoimmune diseases. To our knowledge, no studies have reported the direct association of cigarette smoke and hypoxic environments with the risk of developing inflammatory and autoimmune diseases.Future studies exploring the risk of autoimmune disease development in smokers at high altitudes, particularly military personnel and mountaineers who are not acclimatized to high-altitude regions, are required to obtain a better understanding of disease risk as well as its management.

Physical activity and autoimmune diseases: Get moving and manage the disease

Physical activity, by definition, is any skeletal muscle body movement that results in energy expenditure. In the last few decades, a plethora of scientific evidences have accumulated and confirmed the beneficial role of physical activity as a modifiable risk factor for a wide variety of chronic diseases including cardiovascular diseases (CVDs), diabetes mellitus and cancer, among others. Autoimmune diseases are a heterogeneous group of chronic diseases, which occur secondary to loss of self-antigen tolerance. With the advent of biological therapies, better outcomes have recently been noted in the management of autoimmune diseases. Nonetheless, recent research highlights the salient role of modifiable behaviors such as physical inactivity on various aspects of the immune system and autoimmune diseases. Physical activity leads to a significant elevation in T-regulatory cells, decreased immunoglobulin secretion and produces a shift in the Th1/Th2 balance to a decreased Th1 cell production. Moreover, physical activity has been proven to promote the release of IL-6 from muscles. IL-6 released from muscles functions as a myokine and has been shown to induce an anti-inflammatory response through IL-10 secretion and IL-1β inhibition. Physical activity has been shown to be safe in most of autoimmune diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), inflammatory bowel diseases (IBD), as well as others. Additionally, the incidence of RA, MS, IBD and psoriasis has been found to be higher in patients less engaged in physical activity. As a general trend, patients with autoimmune diseases tend to be less physically active as compared to the general population. Physically active RA patients were found to have a milder disease course, better cardiovascular disease (CVD) profile, and improved joint mobility. Physical activity decreases fatigue, enhances mood, cognitive abilities and mobility in patients with MS. In SLE patients, enhanced quality of life and better CVD profile were documented in more physically active patients. Physically active patients with type 1 diabetes mellitus have a decreased risk of autonomic neuropathy and CVD. Both fibromyalgia and systemic sclerosis patients report decreased disease severity, pain, as well as better quality of life with more physical activity. Further, SSc patients improve their grip strength, finger stretching and mouth opening with increased level of exercise. The purpose of this paper is to review the clinical evidence regarding the safety, barriers to engagement, and impact of physical activity on autoimmune diseases.

Is the hygiene hypothesis relevant for the risk of multiple sclerosis?

The hygiene hypothesis, suggesting that low exposure to pathogens early in life can increase the risk for immune-mediated diseases, has been proposed as an explanation for the increase in incidence of allergy and autoimmune diseases in industrialized countries during the last decades. Several aspects of the hygiene hypothesis have been related to MS. Already in 1966, the risk of MS was suggested to be higher in individuals with high hygienic standard during childhood. Further, an episode of infectious mononucleosis is an independent risk factor for MS and can be regarded as an indicator of low exposure to pathogens early in life, as infection with Epstein-Barr virus often is asymptomatic when it occurs in young children. Conflicting results have been reported regarding number of siblings, attendance in a day care center and exposure to animals during childhood in relation to MS risk, but common childhood infections and vaccinations do not seem to influence the risk of MS. In line with the hygiene hypothesis, two large meta-analyses have recently shown that infection with Helicobacter pylori is negatively correlated with MS. Moreover, a protective influence of helminth infection on MS has been observed in several, small clinical studies, but more knowledge is needed before a potential role of helminth-derived therapy in MS is determined. Also, it has been hypothesized that infection with the parasite Toxoplasma gondii could be protective against MS.

[The influence of solar and geomagnetic activity on the risk of multiple sclerosis (results of correlation and regression analysis)]

AIM

Multiple sclerosis (MS) develops as a result of an interaction between genetic and environmental factors, among them solar (SA) and geomagnetic activity (GMA) attract the particular attention. An impact of SA and GMA on intrauterine and postnatal period in MS was studied.

MATERIAL AND METHODS

The study included 358 patients with MS. Correlation (CA) and regression analysis (RA) were used to study the effects of SA and GMA during intrauterine period, the 1st year of life, a year of disease onset, a year before the onset.

RESULTS AND CONCLUSIONS

CA revealed the association between the MS onset and mean values of kp-index in the onset year and the year before the onset year, number of days with kp≥4 and kp≥5 in the onset year and the year before the onset year, mean SFU in the onset year. RA revealed the association between the MS onset and mean kp in the year before the onset year and in the onset year, number of days with kp≥7 in the onset year and the year before the onset year, mean kp during pregnancy, number of days with kp≥7 in the 1st year of life and during pregnancy. The influence of high GMA during pregnancy and in the 1st year of life increases the MS risk in the future and the high GMA predisposes to the MS onset in adults. The practical value of the study is that predicting the GMA changes we can try to prevent the onset and relapses in the risk groups.

Evaluating the association of allergies with multiple sclerosis susceptibility risk and disease activity in a pediatric population

BACKGROUND

Multiple sclerosis (MS) and allergies are both considered to be related to imbalanced Th1 and Th2 immune responses. Previous studies evaluating the relationship between MS and allergies provide conflicting results.

OBJECTIVE

To assess allergies and asthma as risk factors for MS and as predictors of MS relapses in a pediatric cohort.

METHODS

The environment and genetic risk factors for pediatric MS study is a national case-control project with 16 participating US sites. An environmental questionnaire is used that includes history of allergies in the first five years of life. Case-control data are entered in the pediatric MS Network database and cases at 12 of the 16 sites enter relapse data prospectively. Annualized relapse rate was calculated for patients with follow-up and adjusted for age at disease onset, gender, race, ethnicity, and use of disease-modifying therapy (DMT).

RESULTS

We included 271 cases (mean age at disease onset of 15.7years and 62% female) and 418 controls. Relapse data were available for 193 cases. There was no difference in prevalence of allergies or asthma between cases and controls. Patients with food allergies had fewer relapses compared to patients without food allergies (0.14 vs 0.48, p=0.01).

CONCLUSIONS

While allergies and asthma are not associated with pediatric MS, cases with food allergies have fewer relapses compared to those without food allergies.

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.

Risk factors of early onset of MS in women in reproductive age period: survival analysis approach

The incidence of multiple sclerosis (MS) has doubled in over the last decades in women, whereas it has been almost unchanged in men. The purpose of this study was to investigate the risk factors of early onset multiple sclerosis in women during reproductive years. A retrospective longitudinal study conducted on 200 women aged 15 to 50 years with MS, registered by the MS Society in Isfahan. Data gathering was fulfilled by standard questionnaire including variables about reproductive period, demographic characteristics, and history of diseases. Kaplan-Mayer with log-rank test and Cox regression models were used in predicting of the age of effective factors in onset of MS. P values less than 0.05 were considered statistically significant. The mean age of studied women was 31.77 ± 8.13 years and the mean and median age of onset the symptoms of MS was 26.79 ± 7.77 and 26 years, respectively. Based on the cox results occurring menarche at 15 years and higher increase the risk of MS 2.8-fold than those their menarche occurred at 12 years and lower (HR: 2.81, 95 % CI; 1.58-4.98).In addition, having only one pregnancy is related to higher risk of MS than other parities and increase the risk of MS 4.5-fold comparing to without parities. Age of menarche and parity numbers was the most important reproductive factors of MS in women. Nevertheless, history of autoimmune diseases, animal bite, childhood disease, family history of MS, regional area (tropical), and living in rural area were not related to early onset of MS.

Cigarette smoking and autoimmune disease: what can we learn from epidemiology?

Cigarette smoking has been causally linked to the development of multiple autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, Graves' hyperthyroidism, and primary biliary cirrhosis, among others. We review the known biologic effects of cigarette smoke, in particular its actions on the immune system, and the epidemiologic evidence associating smoking with increased risk of each of these autoimmune diseases. Interactions between cigarette smoking and genetic and immunologic factors, such as the human leukocyte antigen (HLA)shared epitope, rheumatoid factor, anti-cyclic citrullinated peptide antibodies, and anti-double stranded DNA antibodies, may point to mechanisms in disease pathogenesis.

The risk of smoking on multiple sclerosis: a meta-analysis based on 20,626 cases from case-control and cohort studies

Background. Multiple sclerosis (MS) has become a disease that represents a tremendous burden on patients, families, and societies. The exact etiology of MS is still unclear, but it is believed that a combination of genetic and environmental factors contribute to this disease. Although some meta-analyses on the association between smoking and MS have been previously published, a number of new studies with larger population data have published since then. Consequently, these additional critical articles need to be taken into consideration.

Method. We reviewed articles by searching in PubMed and EMBASE. Both conservative and non-conservative models were used to investigate the association between smoking and the susceptibility to MS. We also explored the effect of smoking on the susceptibility to MS in strata of different genders and smoking habits. The association between passive smoking and MS was also explored.

Results.The results of this study suggest that smoking is a risk factor for MS (conservative model: odds ratio (OR) 1.55, 95% CI [1.48–1.62], p < 0.001; non-conservative model: 1.57, 95% CI [1.50–1.64], p < 0.001). Smoking appears to increase the risk of MS more in men than in women and in current smokers more than in past smokers. People who exposed to passive smoking have higher risk of MS than those unexposed.

Conclusion.This study demonstrated that exposure to smoking is an important risk factor for MS. People will benefit from smoking cessation, and policymakers should pay attention to the association between smoking and MS.

The Role of Environment and Lifestyle in Determining the Risk of Multiple Sclerosis

MS is a complex disease where both genetic and environmental factors contribute to disease susceptibility. The substantially increased risk of developing MS in relatives of affected individuals gives solid evidence for a genetic base for susceptibility, whereas the modest familial risk, most strikingly demonstrated in the twin studies, is a very strong argument for an important role of lifestyle/environmental factors in determining the risk of MS, sometimes interacting with MS risk genes. Lifestyle factors and environmental exposures are harder to accurately study and quantify than genetic factors. However, it is important to identify these factors since they, as opposed to risk genes, are potentially preventable. We have reviewed the evidence for environmental factors that have been repeatedly shown to influence the risk of MS: Epstein-Barr virus (EBV) infection, ultraviolet radiation (UVR) exposure habits /vitamin D status, and smoking. We have also reviewed a number of additional environmental factors, published in the past 5 years, that have been described to influence MS risk. Independent replication, preferably by a variety of methods, may give still more firm evidence for their involvement.

Nicotine impact on the structure of adult male guinea pig auditory cortex

BACKGROUND

A growing body of evidence suggests that chronic cigarette smoking causes detrimental effects on brain morphology.

AIM OF WORK

To study the structural changes in auditory cortex region (Layer V), under the influence of nicotine.

MATERIAL AND METHODS

Three animal groups (10 each) were used; group I (control) and groups IIa and IIb received 3 and 6mg/kg nicotine respectively. The specimens from the auditory cortex were examined using light and electron microscopy and morphometry.

RESULTS

Neurons and blood capillaries of the auditory cortex (layer V), were influenced by chronic nicotine treatment in a dose dependent manner. The neurons and their processes revealed disorganization and dissociation of microtubules. The neuronal cells nucleoli characteristically revealed large fibrillar centers detected by silver stain and ultrastructure. The blood capillaries revealed collapse, irregular lumen, thickened basal lamina, abnormal forms of nuclei and organization of microtubules. Neuroglia revealed marked reactivity. Morphometrically, there was a significant decrease in the thickness of the auditory cortex and the number of light neurons and a significant increase in the number of dark neurons in comparison to the control.

CONCLUSION

Nicotine affects the integrity of the auditory cortex possibly by reducing metabolic and transcription activities.

Genetic, Epigenetic, and Environmental Factors Influencing Neurovisceral Integration of Cardiovascular Modulation: Focus on Multiple Sclerosis

Thought to be an autoimmune inflammatory CNS disease, multiple sclerosis (MS) involves multiple pathologies with heterogeneous clinical presentations. An impaired neurovisceral integration of cardiovascular modulation, indicated by sympathetic and parasympathetic autonomic nervous system (ANS) dysfunction, is among common MS clinical presentations. ANS dysfunction could not only enhance MS inflammatory and neurodegenerative processes, but can also lead to clinical symptoms such as depression, fatigue, sleep disorder, migraine, osteoporosis, and cerebral hemodynamic impairments. Therefore, factors influencing ANS functional activities, in one way or another, will have a significant impact on MS disease course. This review describes the genetic and epigenetic factors, and their interactions with a number of environmental factors contributing to the neurovisceral integration of cardiovascular modulation, with a focus on MS. Future studies should investigate the improvement in cardiovascular ANS function, as a strategy for preventing and minimizing MS-related morbidities, and improving patients' quality of life.

Sociocultural and Demographic Risk Factors for the Development of Multiple Sclerosis in Kuwait: A Case - Control Study

Introduction

Immunological, genetic and environmental factors are believed to play important roles in the pathogenesis of Multiple Sclerosis (MS). There have been many studies on risk factors for MS but these have been mainly in Caucasian populations; robust studies in Arab populations remain relatively uncommon. This study therefore aimed to identify behavioral, socio-cultural, and demographic factors associated with development of MS in Kuwait, a high income Arab country, currently undergoing a demographic transition.

Subjects and methods

In this case- control study, 195 Kuwaiti MS patients and 146 healthy age and sex-matched controls were recruited. Both groups of subjects were interviewed using a structured questionnaire, in relation to anthropometric, socio-cultural and demographic data, residence during the 1990/91 Gulf War and current and past medical history, including medications. We also clinically evaluated, and retrospectively reviewed medical records of patients to derive appropriate clinical information, including associated chronic medical illness requiring long-term treatment.

Results

On multiple logistic regression analysis after adjustment for potential confounders including age, gender and BMI, in all the subjects, a positive associations prevail with presence of MS and some sociocultural and demographic factors, which included non-Bedouin ethnicity (AOR 2, 95% CI 1.0-3.9, p 0.049), positive family history of MS (AOR 10.6, 95% CI 3.0-36.9), p < 0.001), and low daily sunlight exposure of < 15min/day (AOR 5.3, 95% CI 2.7-10.5 p < 0.001). In addition, while 41.8% of MS patients indicated at least one comorbidity, only 26.8% of the controls reported any associated physical illness, with the suggestion that presence of certain comorbidities might increase MS risk (AOR 2.4, 95% CI 1.3-4.7, p < 0.001). Other risk variables such as smoking status and mode of routine outdoor dressing were not significant in all the MS subjects taken as a whole, but demonstrated variably positive associations in the MS subgroup classified as those with established disease and those who were newly diagnosed and drug naïve.

Conclusions

This study suggests that a positive family history of MS and presence of certain comorbidities appeared to be associated with an increased risk of developing MS. In contrast, relatively increased amount of daily sunlight exposure and Bedouin ethnicity appear to somewhat be protective. It is speculated that the relationship of sunlight exposure with MS might be due to vitamin D availability, and is deserving of further study.

A systematic review of the incidence and prevalence of comorbidity in multiple sclerosis: overview

Background:

Comorbidity is an area of increasing interest in multiple sclerosis (MS).

Objective:

The objective of this review is to estimate the incidence and prevalence of comorbidity in people with MS and assess the quality of included studies.

Methods:

We searched the PubMed, SCOPUS, EMBASE and Web of Knowledge databases, conference proceedings, and reference lists of retrieved articles. Two reviewers independently screened abstracts. One reviewer abstracted data using a standardized form and the abstraction was verified by a second reviewer. We assessed study quality using a standardized approach. We quantitatively assessed population-based studies using the I² statistic, and conducted random-effects meta-analyses.

Results:

We included 249 articles. Study designs were variable with respect to source populations, case definitions, methods of ascertainment and approaches to reporting findings. Prevalence was reported more frequently than incidence; estimates for prevalence and incidence varied substantially for all conditions. Heterogeneity was high.

Conclusion:

This review highlights substantial gaps in the epidemiological knowledge of comorbidity in MS worldwide. Little is known about comorbidity in Central or South America, Asia or Africa. Findings in North America and Europe are inconsistent. Future studies should report age-, sex- and ethnicity-specific estimates of incidence and prevalence, and standardize findings to a common population.

The incidence and prevalence of comorbid gastrointestinal, musculoskeletal, ocular, pulmonary, and renal disorders in multiple sclerosis: A systematic review

Background:

As new disease-modifying therapies emerge a better knowledge of the risk of comorbid disease in multiple sclerosis (MS) is needed.

Objective:

To estimate the incidence and prevalence of comorbid gastrointestinal, musculoskeletal, ocular, pulmonary, and renal disorders in MS.

Methods:

We systematically reviewed the world literature by searching PUBMED, EMBASE, SCOPUS, the Web of Knowledge, and reference lists of retrieved articles. For selected articles, one reviewer abstracted data using a standardized form. The abstraction was verified by a second reviewer. The quality of all selected studies was assessed. For population-based studies we quantitatively assessed studies using the I² statistic, and conducted random effects meta-analyses.

Results:

Study designs were heterogeneous with respect to populations, case definitions, and methods of ascertainment. Incidence of the studied comorbidities was rarely reported. Irritable bowel syndrome and chronic lung disease had a prevalence of more than 10% in the MS population. Irritable bowel syndrome, fibromyalgia, cataracts and glaucoma were more common than expected in the MS population.

Conclusion:

Although they have been the subject of less study than other comorbidities, irritable bowel syndrome, arthritis, and chronic lung disease are common in the MS population and occur more often than expected when compared to the general population.

A systematic review of the incidence and prevalence of autoimmune disease in multiple sclerosis

Background:

As new therapies emerge which increase the risk of autoimmune disease it is increasingly important to understand the incidence of autoimmune disease in multiple sclerosis (MS).

Objective:

The purpose of this review is to estimate the incidence and prevalence of comorbid autoimmune disease in MS.

Methods:

The PUBMED, EMBASE, SCOPUS and Web of Knowledge databases, conference proceedings, and reference lists of retrieved articles were searched, and abstracts were independently screened by two reviewers. The data were abstracted by one reviewer using a standardized data collection form, and the findings were verified by a second reviewer. We assessed quality of the included studies using a standardized approach and conducted meta-analyses of population-based studies.

Results:

Sixty-one articles met the inclusion criteria. We observed substantial heterogeneity with respect to the populations studied, methods of ascertaining comorbidity, and reporting of findings. Based solely on population-based studies, the most prevalent autoimmune comorbidities were psoriasis (7.74%) and thyroid disease (6.44%). Our findings also suggest an increased risk of inflammatory bowel disease, likely uveitis and possibly pemphigoid.

Conclusion:

Fewer than half of the studies identified were of high quality. Population-based studies that report age, sex and ethnicity-specific estimates of incidence and prevalence are needed in jurisdictions worldwide.

Environmental exposures and the risk of multiple sclerosis investigated in a Norwegian case-control study

Background

Several environmental exposures, including infection with Epstein-Barr virus, low levels of vitamin D and smoking are established risk factors for multiple sclerosis (MS). Also, high hygienic standard and infection with parasites have been proposed to influence MS risk. The aim of this study was to investigate the influence of various environmental exposures on MS risk in a Norwegian cohort, focusing on factors during childhood related to the hygiene hypothesis.

Methods

A questionnaire concerning environmental exposures, lifestyle, demographics and comorbidity was administrated to 756 Norwegian MS patients and 1090 healthy controls. Logistic regression was used to calculate odds ratio (OR) with 95% confidence interval (CI) for the risk of MS associated with the variables infectious mononucleosis, severe infection during childhood, vaccination and animals in the household during childhood. Age, gender, HLA-DRB1*15:01, smoking and infectious mononucleosis were included as covariates. General environmental exposures, including tobacco use, were also evaluated.

Results

Infectious mononucleosis was confirmed to be significantly associated with increased MS risk, also after adjusting for the covariates (OR = 1.79, 95% CI: 1.12-2.87, p = 0.016). The controls more often reported growing up with a cat and/or a dog in the household, and this was significant for ownership of cat also after adjusting for the covariates (OR = 0.56, 95% CI: 0.40-0.78, p = 0.001). More patients than controls reported smoking and fewer patients reported snuff use.

Conclusions

In this Norwegian MS case–control study of environmental exposures, we replicate that infectious mononucleosis and smoking are associated with increased MS risk. Our data also indicate a protective effect on MS of exposure to cats during childhood, in accordance with the hypothesis that risk of autoimmune diseases like MS may increase with high hygienic standard.

Traumatic Injury and Multiple Sclerosis: A Systematic Review and Meta-Analysis

A systematic review/meta-analysis of literature addressing a possible association between traumatic injury and onset of multiple sclerosis was conducted. Medline, Embase, Cochrane DSR, Ovid HealthStar, CINAHL, ISI Web of Science and Scopus were searched for analytical studies from 1950 to 2011. Two investigators independently reviewed articles for inclusion, assessing their quality using the Newcastle-Ottawa Scale. Of the 13 case-control studies included, 8 were moderate quality and 5 low; of the 3 cohort studies 2 were high and 1 moderate. Meta-analysis including moderate and low quality case-control studies produced a modest but significant odds ratio: 1.41 (95% confidence interval: 1.03, 1.93). However, when low quality studies were excluded, the resulting odds ratio was non-significant. Cohort studies produced a non-significant standardized incidence ratio of 1.00 (95% confidence interval: 0.86, 1.16). These findings support the conclusion that there is no association between traumatic injury and multiple sclerosis onset; more high quality cohort studies would help to confirm this observation.

Physical and social environment and the risk of multiple sclerosis

BACKGROUND

The incidence of multiple sclerosis (MS) in Denmark has doubled in women since 1970, whereas it has been almost unchanged in men. The rapid epidemiological changes suggest that environmental factors may modify the risk of MS.

OBJECTIVES

To investigate whether occupational, physical, or social environmental influence the risk of MS differently in women than in men.

METHODS

The cohort consists of all 1403 patients (939 women, 464 men) identified through Danish Multiple Sclerosis Registry aged 1-55 of years at clinical onset between 2000 and 2004, and up to 25 control persons for each case, matched by sex, year of birth and residential municipality. The same cohort was previously used to investigate the influence of the reproductive factors on the risk of MS.

RESULTS

By linkage to Danish population registers we found a slight albeit statistically significant excess for 6 female MS patients who had been employed in agriculture: OR 3.52; 95% CI 1.38-9.00, p=0.008 (0.046 when corrected for multiple significance) and a trend for exposure to outdoor work in 12 : OR 1.94, 95% CI 1.06-3.55, p=0.03 (0.09 when corrected for multiple significance), but the numbers of cases were small, and the effects were not found in men. Educational level, housing conditions in youth, or the presence of children unrelated by blood in the household did not influence the risk of MS.

CONCLUSIONS

Our study did not reveal any additional factors beyond the previously published childbirths which could explain the extent of the MS incidence increase in women.

Adverse socioeconomic position during the life course is associated with multiple sclerosis

BACKGROUND

Adverse socioeconomic position (SEP) in childhood and adulthood is associated with a proinflammatory phenotype, and therefore an important exposure to consider for multiple sclerosis (MS), a complex neuroinflammatory autoimmune disease. The objective was to determine whether SEP over the life course confers increased susceptibility to MS.

METHODS

1643 white, non-Hispanic MS case and control members recruited from the Kaiser Permanente Medical Care Plan, Northern California Region, for which comprehensive genetic, clinical and environmental exposure data have been collected were studied. Logistic regression models investigated measures of childhood and adulthood SEP, and accounted for effects due to established MS risk factors, including HLA-DRB1*15:01 allele carrier status, smoking history, history of infectious mononucleosis, family history of MS and body size.

RESULTS

Multiple measures of childhood and adulthood SEP were significantly associated with risk of MS, including parents renting versus owning a home at age 10: OR=1.48, 95% CI 1.09 to 2.02, p=0.013; less than a college education versus at least a college education based on parental household: OR=1.28, 95% CI 1.01 to 1.63, p=0.041; low versus high life course SEP: OR=1.50, 95% CI 1.09 to 2.05, p=0.012; and low versus high social mobility: OR=1.74, 95% CI 1.27 to 2.39, p=5.7×10(-4).

CONCLUSIONS

Results derived from a population-representative case-control study provide support for the role of adverse SEP in MS susceptibility and add to the growing evidence linking lower SEP to poorer health outcomes. Both genetic and environmental contributions to chronic conditions are important and must be characterised to fully understand MS aetiology.