Smoking and Inflammatory Activity in Patients with Relapsing-Remitting Multiple Sclerosis : A retrospective review of medical history of patients withMultiple sclerosis at Karlstad Central hospital

1 Örebro University

School of Medical Sciences Medicine D

Degree project, 30 ECTS January 2018

Smoking and Inflammatory Activity in

Patients with Relapsing-Remitting

Multiple Sclerosis

A retrospective review of medical history of patients with

Multiple sclerosis at Karlstad Central hospital

Version 2

Author: Linnea Hartman Supervisor: Rune Johansson, MD

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ABSTRACT

Introduction: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system primarily affecting young adults, leading to accumulating neurological disability. Cigarette smoking has been shown to have a negative impact on MS susceptibility, progression and possible severity, hypothesized of increasing the inflammatory activity.

Aim: Investigate if cigarette smokers with relapsing-remitting MS (RRMS) have an increased inflammatory activity at diagnosis and higher ratio of treatment failure towards disease-modifying-treatment than non-smokers.

Material and Methods: Retrospective data for 53 patients (83 % female) with RRMS diagnosis received between 2013 and 2017 (median age at diagnosis 36.0), comprising non-smokers (n=40) and current non-smokers (n=13). Disease activity (annualized relapse rate, lesions detected by magnetic resonance imaging (MRI) and neurofilament light in spinal fluid) was evaluated at diagnosis. Treatment failure was evaluated in 36 patients with up to 4 years of follow-up.

Results: A higher proportion of smokers presented at diagnosis with active T1 gadolinium-enhanced lesions than smokers, 76.9 % and 67.5 % respectively, however non-significant. Patients treated with first-line disease-modifying-drugs (DMD) were more likely to present with treatment failure than patients treated with second-line DMD (p=0.053). Conclusion: We found no significant association between smokers and inflammatory activity at diagnosis or regarding treatment failure at follow-up. Results may be affected by the small patient sample size and different time in follow-up. More studies are needed to investigate the impact of smoking and inflammatory activity in MS.

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1.INTRODUCTION

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2.AIM

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3.MATERIAL AND METHODS

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3.1. Standard protocol approvals ... 6

3.2. Study design and population... 6

3.3. Inclusion- and exclusion criteria... 7

3.4. Figure 1a, 1b Study population selection and loss to follow-up... 7

3.5. Medical records reviewed ... 7

3.6. Inflammatory activity measurements... 8

3.7. Evaluation of treatment failure ... 8

3.8. Statistical analysis ... 9

3.9. Ethical consideration ... 9

4.RES ULTS

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4.1. Study population ... 9

4.2. Table 1 Baseline characteristics at diagnosis... 10

4.3. Inflammatory activity ... 11

4.4. Treatment failure ... 11

4.5. Table 2 Treatment failure at follow- up... 11

5.DISCUSS ION ... 12 6.CONCLUS ION

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Populärvetenskaplig sammanfattning (Swe) ... 23

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MS Multiple sclerosis CNS Central nervous system

RRMS Relapsing-remitting Multiple sclerosis CIS Clinically isolated syndrome

RIS Radiologically isolated syndrome

SPMS Secondary-progressive Multiple sclerosis DMT Disease-modifying-treatment

MRI Magnetic resonance imaging BMI Body mass index

DMD Disease-modifying-drugs ARR Annualized relapse rate NFL Neurofilament light CSF Cerebrospinal fluid T1Gd+ T1 gadolinium-enhanced IQR Interquartile range

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I

Multiple sclerosis (MS) is an autoimmune and inflammatory disorder of the central nervous system (CNS). Within inflammatory lesions, nerve impulse signaling is disrupted due to damaging of axons, initially from demyelination, resulting in symptom initiation [1]. The majority of MS patients (80-90 %) are initially diagnosed with the relapsing-remitting form (RRMS) [1] with disease onset between 20 and 45 years of age with female predominance [1,2]. Approximately 10-20 % of MS patients present with the progressive form, with disease onset at the age of 40 or older [1]. The character of the disease course is of importance concerning treatment options and prognosis [3,4].

Sweden has among the highest nationwide MS prevalence, 189 per 100 000, based on health and population registries [5]. Although the aetiology of MS remains unclear, disease onset is believed to involve a complicated interplay between multiple risk factors, including genetic susceptibility [6], environmental factors, e.g. exposure to infections agents [7], vitamin deficiencies [8], smoking [9,10] and overweight [11]. No symptom or investigation finding is unique for MS, accordingly, diagnosis is based on multifactorial criteria (the 2010 revised McDonald criteria) [12,13]. Unfulfilled MS criteria at clinical debut, clinically isolated syndrome (CIS), and suspected MS lesions detected by MRI without presented clinical symptoms, radiologically isolated syndrome (RIS) [3], may later on in life develop into clinically definite MS [14,15].

In early relapsing-remitting disease course inflammation is transient, remyelination occurs and symptoms subside with full or partial recovery [1]. Clinical manifestations include motor, sensory, visual and autonomic systems and differ among patients and within patient over time [1]. Remyelination potential eventually declines for the majority of RRMS patients, leading to permanent axonal degeneration and plaque formation. Hence, resulting in accumulating neurological disability, independent of relapses [1], classified as secondary-progressive disease course (SPMS) [3]. Patients may develop fatigue, depression and increasing disability impairment. This may affect patients working capacity and reduce quality of life [16].

6 Progression prognosis appears to be affected by sex [17], age at disease onset [17,18], received disease-modifying-treatment (DMT) [18,19] and severity in early disease course, correlating to inflammatory activity, high relapse rate and MRI lesions [15,17]. However, studies show conflicting results [17–19]. Follow-up to examine the extent of inflammatory activity and progression is essential for treatment evaluation [17] and to detect eventual treatment failure [20]. Repeated MRI scans are of importance [3,12] since inflammation could be present despite meagre symptoms [12].

Accumulating evidence indicate that cigarette smoking is a risk factor for early conversion from RRMS to SPMS, however, showing various levels of significant results [9,21–23]. The mechanism for this association is currently unknown, however one possibility could be that smoking increases the inflammatory activity [22,24,25]. Previous studies have found a correlation between smoking and increased disease activity in relapse rate [23], active MRI lesions and brain atrophy, associated with inflammatory activity and disease progression [24]. Smoking cessation has been shown to reduce disease activity and progression rate [22,23,26].

A

The aim of this study was to investigate if current cigarette smokers with clinically definite RRMS have an increased inflammatory activity at diagnosis, and higher ratio of treatment failure towards DMT, than non-smokers at follow-up.

M

M

The study data was obtained under a protocol approved by the Head Manager of the Neurological Department at Karlstad Central hospital.

Study design and population

Patients were derived from the national Swedish MS Registry (SMSreg) [27]. The methodology of this study consisted of a review of medical records, collected retrospective between January 2013 and October 2017 by means of regular patient visits (mean 12.5 months ±SD 3.4 between visits) with reporting of history, treatment, investigation results and regular MRI scans (mean 12.4 months ±SD 3.7 between scans).

7 Inclusion- and exclusion criteria

Inclusion criteria were patients with clinically definite RRMS diagnosis received between year 2013 and 2017, aged 18 to 55 at diagnosis, with medical records within the neurological department of Karlstad Central hospital (n=84). Exclusion criteria were patients with blocked medical history or unrecorded smoking status or patients that were ex-smokers at diagnosis. Patients with unfulfilled McDonald criteria [3,12] at diagnosis were excluded (n=24 [myelitis=5, CIS=17, paraesthesia=2]). The final patient selection (n=53) is presented in figure 1a. Patients were followed up to 4 years subsequent diagnosis, see figure 1b.

Figure 1a: Flow chart of the study population selection.

Figure 1b: Loss to follow- up during 4 years subsequent diagnosis.

SMS-reg: Swedish MS registry, PPMS: primary-progressive MS, SPMS: secondary-progressive MS, PRMS: secondary-progressive-remitting MS, RRMS: relapsing-remitting MS.

Medical records reviewed

Patient characteristics investigated were sex, age at diagnosis, time to diagnosis from clinical onset (date of the first manifestation of the disease or any neurological sign indicative of MS identified by neurologist) and BMI, categorized into (1) normal and overweight (18.5-29.9) and (2) obesity (>30) [28].

Smoking status was investigated at time of first clinical presentation or diagnosis visit as well as during follow-up. Patients were grouped as non-smokers or current smokers. Patients with unknown smoking status or patients that quit smoking the following year was excluded from the following analyses.

8 DMT was categorized as (1) first-line treatment (dimethyl fumarate, teriflunomide, interferons, glatiramer acetate) and (2) second-line treatment (natalizumab, rituximab, alemtuzumab, fingolimod) [4].

Inflammatory activity measurements

Annualized relapse rate (ARR) and MRI lesions were evaluated since these are established clinical measurements to evaluate disease activity and treatment efficacy [12,20]. Neurofilament light (NFL) in cerebrospinal fluid (CSF) analysis was also included. This method is in Karlstad now routinely included in follow-up since available data indicate it is a valid marker for inflammatory activity [13,29].

Relapses were defined as acute development of new symptoms, or worsening of existing symptoms, lasting for >24 h, in absence of fever or infection [12], assessed by neurologists. If new symptoms developed within a month from a relapse, this was accounted to the previous relapse.

MRI activity was measured by T2 lesions and T1 gadolinium-enhanced lesions (T1Gd+) [12]. Lesions for each patient was primarily assessed by radiologists and categorized into stratified groups; (1) no lesions, (2) 1-3, (3) 4-9, (4) 10-19 or (5) >20 lesions. Cerebral (100 % of the examined patients) and spinal (91.1 % of the examined patients) MRI were evaluated and lesions were merged into one of the stratified groups.

NFL analyses consisted of occasional debut value, categorized as (1) below or (2) above reference value [29].

Evaluation of treatment failure

Treatment failure, or suboptimal response to DMT, was evaluated by specialists in neurology during follow-up. However, considered if relapses, active T1Gd+ lesion or >2 new/enlarged T2 lesions occurred during treatment [20]. Patients not receiving DMT or disrupted treatment (n=3) were excluded from the analysis. Patients were followed up to 4 years subsequent diagnosis, see figure 1b. Time of follow-up is presented for the different patient categories, sex, age, smoking status and treatment selection, investigated in treatment failure. The mean follow-up time in months for the 36 patients investigated was measured as time to treatment failure or total observational time in the study.

9 Statistical analysis

Data were described as frequencies and percentages or presented as means (±SD) for data with normal distribution, or medians (range or interquartile range [IQR]) for data with non-normal distribution. Patient characteristics were compared between non-smokers and current smokers at baseline and regarding treatment failure, using Chi square and Fisher exact test for categorical variables, and Mann-Whitney U-test for ordinal and continuous variables with non-normal distribution. The statistical tests were 2-sided and performed at the 0.05 level of significance using the Statistical Package for the Social Sciences (SPSS) version 23.

Ethical considerations

No ethical application was submitted to the Regional Ethical Review Board. Collection of medical records was made under a protocol approved by the Head Manager of the Neurological Department at Karlstad Central hospital. Patients were not asked for consents, nor informed about the study. Patients’ data were de-identified and handled only by individuals performing the study.

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Study population

Patients are presented in groups, non-smokers (n=40) and current smokers (n=13), at diagnosis in table 1. All patients are included (n=53), regardless of year of diagnosis. The investigated patient sample comprised 24.5 % current smokers at diagnosis, resulting in un-evenly distributed groups. The groups were un-evenly distributed in female sex (77.5 % and 76.9 % respectively), median age (IQR) 35.0 (27.8-43.5) and 35.0 (27.5-45.5) respectively, and were non-significantly, un-evenly distributed over the years of diagnosis. Smokers had slight higher median months in time from onset to diagnosis (range, IQR) than non-smokers, 7.3 (0.6-164.5, 2.0-18.1) and 4.6 (0.3-118.1, 1.4-16.9) respectively, and were more likely to be obese, 37.5 % and 13.6 % respectively, however non-significant and with missing BMI values (n=23).

10 Table 1: Comparison of baseline patient characteristics between non-smokers (n=40) and current smokers (n=13) at diagnosis.

Values represent number (%) or median [range or IQR].

NS: not significant, IQR: interquartile range, BMI: body mass index, ARR: annualized relapse rate, MRI: magnetic resonance imaging, Gd+: gadolinium enhanced, NFL: neurofilament light.

Patient characteristics Non-smoker Current smoker p-value

Sex female n (%) 31 (77.5) 10 (76.9) NS

Median age at diagnosis [IQR] 35.0 [37.8-43.5] 35.0 [27.5-45.5] NS

Year of diagnosis n (%) 2013 2014 2015 2016 2017 15 (37.5) 7 (17.5) 2 (5.0) 10 (25.0) 6 (15.0) 2 (15.4) 3 (23.1) 4 (30.8) 3 (23.1) 1 (7.7) NS

Median months in time from onset to diagnosis [range, IQR]

4.6 [0.3-118.1, 1.4-16.9] 7.3 [0.6-164.5, 2.0-18.1] 0.584 BMI n (%) <29.9 >30 Missing 19 (86.4) 3 (13.6) 18 5 (62.5) 3 (37.5) 5 0.300

Median ARR [IQR] 1.00 [1.00-1.75] 1.00 [1.00-1.50] 0.584

MRI T2 n (%) 1-3 lesions 4-9 lesions 10-19 lesions >20 lesions 7 (17.5) 12 (30.0) 11 (27.5) 10 (25.0) 2 (15.4) 3 (23.1) 6 (46.2) 2 (15.4) 0.949 MRI T1Gd+ n (%) 0 lesions 1-3 lesions 4-9 lesions 13 (32.5) 21 (52.5) 6 (15.0) 3 (23.1) 7 (53.8) 3 (23.1) 0.424

MRI spinal cord n (%) 35 (87.5) 13 (100.0)

NFL n (%) Below Above Missing n 7 (50.0) 7 (50.0) 26 1 (14.3) 6 (85.7) 7 0.174 Treatment received n (%) No treatment First-line Second-line 1 (2.5) 22 (55.0) 17 (42.5) 6 (46.2) 7 (53.8) 0.441

11 Inflammatory activity

There was no significant association between smoking status and inflammatory activity regarding ARR, MRI lesions and NFL analyses at diagnosis. However, a larger proportion of smokers presented with active T1Gd+ lesions (1-9 lesions) than non-smokers, 76.9 % and 67.5 % respectively, and of NFL above reference value, 85.7 % and 50.0 % respectively, however with missing values in NFL analyses (n=33). Distribution of T2 lesions and median ARR were similar in the groups. MRI spinal cord was made in 87.5 % of non-smokers and in 100 % of smokers. A slight higher proportion of smokers received second-line treatment than non-smokers (53.8 % and 42.5 % respectively), however non-significant.

Treatment failure

Sex, age and smoking status had no significant impact on the patients that presented with treatment failure during follow-up (n=5), see table 2. All five patients presented with treatment failure within 28 months subsequent diagnosis. Second-line treated patients were less likely to present with treatment failure than first-line treated patients (p=0.053). The mean time in follow-up differed above all in sex and smoking status, accordingly, in categories with un-even patient distribution.

Table 2: Sex, age, smoking status and treatment selection distributed over cases of treatment failure (n=5) or not (n=31) during follow-up.

Patient characteristics

Treatment failure

No treatment failure

p-value Mean time to follow-up in months [SD] Female n (%) 4 (80.0) 24 (77.4) 1.000 24.7 [12.0]

Male n (%) 1 (20.0) 7 (22.6) 36.2 [9.7]

Age < median value 35.0 n (%) 3 (18.8) 13 (81.3) 0.637 27.5 [13.5]

Age > median value 35.0 n (%) 2 (10.0) 18 (90.0) 27.0 [11.8]

Non-smoker n (%) 4 (80.0) 26 (83.9) 1.000 28.2 [12.5]

Current smoker n (%) 1 (20.0) 5 (16.1) 22.2 [11.2]

First-line treatment n (%) 5 (100.0) 15 (48.4) 0.053 26.2 [13.0]

Second-line treatment n (%) 0 (0.00) 16 (51.6) 28.6 [11.8]

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D

During the past decade various new effective treatment options have provided new insight in MS pathogenesis as well as made disease control possible by reducing inflammatory activity and delay disease progression [30]. Several studies have focused on evaluating the hazard of smoking in MS, proving smoking to accentuate progression [9,21–23] and in a dose-response manner, increase disease susceptibility [10] and disability [23]. There is still need for investigating other potential lifestyle and modifiable risk factors in MS. A reliable doctor-patient relationship is essential in improving doctor-patient motivation and compliance. By limiting and avoiding potential risk factors in combination with early, individualized treatment to achieve disease control, disease progression could be delayed [9,19,31] and improve patient working capacity and quality of life [32].

In this study we found no significant association between non-smokers and current smokers regarding inflammatory activity at diagnosis or at follow-up evaluating treatment failure. Our study population comprised 24.5 % current smokers at diagnosis, with no sex or age predominance, representing a higher smoking prevalence than estimated in the Swedish population [33]. Recent studies have shown both lower and higher smoking rates in MS patients [21,22,26]. One hypothesis for the possible increased smoking prevalence could be the correlation between smoking and increased MS susceptibility [9], however, there is also a risk for incorrect smoking documentation in the medical records in our study. The smokers in this study may in fact be ex-smokers or sporadic smokers, consequently, affecting the results. The non-smoking and current smoking groups were representative in female predominance and had similar age distribution. The un-even distribution of patients diagnosed over the five years investigated was not considered important since routines and treatment regime has not changed considerably [3,20]. The difference in median months from onset to diagnosis between the groups was due to a few outliers, according to the wide range and similar IQR. The majority of the patients were diagnosed up to 2 years after onset. A greater time between first clinical onset and diagnosis may suggest that the patients have a more benign disease course if the relapse was modest [15], resulting in not receiving or not seeking the proper medical care, until the occurrence of the second relapse. Interpretation of the BMI analyses is un-reliable due to the many missing values. In larger studies, smoking has been shown to correlate to lower BMI than in non-smoking patients [34]. Obesity has been shown to worsen disease course in several autoimmune diseases and to be of relevance in MS susceptibility [11], however lacking evidence for increasing the inflammatory activity in MS [35].

13 The slim differences in inflammatory activity regarding ARR, MRI lesions and NFL observed between smokers and non-smokers at diagnosis were non-significant in our study. Due to the many missing values in the NFL analysis, we make no further interpretation of this result. The proportion of active T1Gd+ lesions at diagnosis was slightly increased in smokers compared to non-smokers. However, median ARR and distribution of T2 lesions were similar between the groups. Smokers were in a higher extent examined with MRI spinal cord than smokers. This could result in a higher amount of lesions in the smoking group than in the non-smoking group. However, this did not have a crucial effect in the final analysis since MRI lesions were stratified. The main reason for MRI examination of the spinal cord is if patients present with suspected spinal relapses [12]. The slight difference in treatment selection between the groups may correlate to interpreted higher disease activity in the smoking group. However, patients’ requests may have influenced the selection. Few recent studies have investigated the association between cigarette smoking and inflammatory activity, and with conflicting results [22,24,25]. In a cohort of 368 MS patients, Zivadinov et al found a correlation between ever-smokers (comprising current and ex-smokers) and increased MRI lesions, both of active T1Gd+ and T2 lesions, as well as a greater proportion of brain atrophy than in never-smokers. Suggestive of correlating to increased inflammatory activity and disease progression [24]. Di Pauli et al conducted a cohort of 128 CIS patients and showed an association between smokers and higher risk of conversion from CIS to clinically definite MS over 3 years with a hazard ratio of 1.8 (95 % confidence interval, 1.2-2.8) compared to non-smokers [25]. Hence, implying that non-smokers have an increased early inflammatory activity [15]. In a cross-sectional cohort of 2469 MS patients, Weiland et al found that active smoking did not affect relapse rate or disease activity, however a greater time since cessation among ex-smokers was associated with a lower level of disease activity and relapse rate [22]. In our study, patients presenting with treatment failure were few and the patient characteristics investigated including smoking status were non-significant. However, first-line treated patients were more likely to present with treatment failure, consistent with other studies reporting second-line treatment to be more efficient [4,31,36], however, with unknown long-term effects [30]. The continuous loss to up and the different time span in follow-up complicates the analyses. Females and current smokers had the shortest mean time in follow-up. The main error of this analysis is that additional patients may have experienced treatment failure later in the disease course than in the time observed. Accordingly, no certain conclusions can be made. The inflammatory activity in MS is at its highest in early disease

14 course [1]. Regardless of DMT exposure, inflammation eventually declines and is replaced by disability accumulation, however with worsened prognosis if un-treated [1,18,19]. Accordingly, treatment failure is more frequent, and important to detect in early disease course [17,20]. Impaired treatment response may correlate to increased disease activity and inflammation as well as if patients develop neutralizing antibodies towards DMD’s, this risk being increased in smokers [37,38].

The relationship between smoking and neoplastic, vascular, cardiac and respiratory diseases as well as infections and premature mortality, is well established [34]. The mechanism by which smoking influences MS susceptibility, disease progression and possible activity is yet to be discovered. Several mechanisms may be of interest. Nicotine has been shown to increase blood-brain-barrier permeability [39], suggested to be an initiating factor in MS development [1]. However, tobacco snuff use has been shown not to increase MS risk [40,41]. Furthermore, inhalation of non-nicotine components of cigarette smoke are more influential than nicotine in MS susceptibility [41]. This may indicate that the irritation of cigarette smoke in the lungs trigger the pro-inflammatory effect [42], or increase the risk of upper respiratory tract infections, a risk factor for MS relapses [43]. Cigarette smoke contains a variable of harmful components as well as promoting production and exposure of nitric oxide and carbon monoxide. All of these components may account for direct neuronal toxicity and degeneration [44,45], characterising disease progression [1], or indirectly due to immunological profile alterations [46,47] in both innate and adaptive immunity [48]. Additionally, exposure to cigarette smoke correlate to increased susceptibility of several autoimmune diseases [48]. Interactions between smoking and specific HLA genes [47], Epstein Barr virus infections [49] and decreased vitamin D levels [8] have shown a significant exponential increase in MS susceptibility [47,49] and possible risk of relapses [8].

Smoking cessation is beneficial [34]. Several studies have shown that smoking cessation reduces disease activity and progression rate [22,23,26], however indicating that the earlier patients quit smoking, the greater is the risk reduction [22,26]. Smoking MS patients have been shown to have significantly reduced quality of life compared to non-smoking MS patients, correlating to worsening health outcome and disability [22,26]. Smoking cessation may improve quality of life [22,26] as well as facilitate physical activity, proved beneficial in MS disease [50].

15 The limitations of this study include the non-blinded retrospective review made by the single author, as well as the credibility of patient reported data, including smoking status. Patients in the study were examined by different neurologists. Elder colleagues were often consulted regarding uncertainties in patient disease activity or treatment evaluation. Smoking duration, amount of cigarettes smoked and passive smoking were unknown. Other important data of genetic factors, vitamin deficiencies, education, progression rates, relapse symptoms and severity were not investigated. Time between patient follow-up and MRI scans differed, mainly due to left outs or rescheduled appointments, contributing to systematic bias. The small sample size received and un-even group distribution imply limited power to detect small differences between the groups and may entail random bias. Patients were observed for different periods of time and missing values in several analyses impeded the statistical interpretation. However, the strengths of this study were that we used a patient population with clinically definite RRMS. Patients had received diagnosis in the past 5 years, limiting bias and changing of routines and treatment selection variety. Inflammatory activity was evaluated with multifactorial measurements, with MRI as one of the main outcomes, which is a sensitive and well-known assessment for subclinical disease activity [12]. Amount of MRI lesions were estimated by radiologists, however in some cases made by specialists in neurology. Treatment failure was evaluated by specialists in neurology. Several studies have examined the correlation of smoking and progression, however only few have investigated the association with inflammatory activity. Matched healthy controls or a complementary questionnaire, to require the amount of smoking in pack-years, could have improved the credibility of the reviewed data in this study. Additionally, may have reduced the amount of missing values and enable correction for the confounding effect.

Further studies need to investigate the impact of smoking and disease activity with larger population sample, evaluating inflammatory activity and progression with multifactorial measurements, as well as to correct for confounders. Investigated patients should have received diagnosis in a few years past since new diagnosis criteria and treatment alternatives contribute to bias. Smoking status should be categorized in total pack-years to enable evaluation of the dose-response relation. Follow-up should be performed with equal observational time span to reduce systematic bias. A well-executed prospective study with the above mentioned criteria should be considered.

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Regardless of our non-significant findings between smoking status and inflammatory activity and treatment failure, accumulating evidence in previous studies indicate that smoking is unfavorable in MS disease, as well as concerning other health aspects and diseases. Evidence also suggests that if patients are exposed to multiple risk factors, the risk for disease susceptibility, activity and progression increases exponentially, implying the importance of reducing all possible modifiable risk factors.

Patients should be informed and involved in the treatment process and one step towards disease control should be to discuss smoking habits, advising smoking patients to quit as well as providing smoking prevention when needed.

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I would like to express my gratitude to Fredrik Lundin, Ph.D. Statistician at the Centre for Clinical Research, County of Värmland, who has helped me with the statistical methods and suggested presentation and interpretation of the results in this study.

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Cover letter

Populärvetenskaplig sammanfattning (Swe) Ethical considerations

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Dear Sirs,

Please consider the enclosed manuscript; “Smoking and inflammatory activity in patients with relapsing-remitting Multiple sclerosis” for publication.

Previous studies have provided evidence regarding cigarette smoking and enhanced risk of disease susceptibility and progression in patients with Multiple sclerosis (MS), mechanism unknown.

In our study we investigated the possible association between smoking and inflammatory activity in MS patients, by means of relapse frequency, MRI lesions and neurofilament light in CSF-analysis at diagnosis as well as occurrence of treatment failure during follow-up. We found that current smokers had slight increased MR T1 gadolinium-enhanced lesions than non-smokers, however non-significant. Smoking did not have a significant impact on treatment failure. Results may be affected due to our small patient sample size.

The publication of this study could encourage further studies to investigate the inflammatory activity and examine the mechanism of smoking in MS disease.

MS primarily affects young adults. Early progression due to high disease activity results in accumulating neurological disability and reduced quality of life as well as complicates treatment options. Smoking cessation is beneficial regarding disease progression and severity. In regard to previous studies and accumulating evidence, smoking MS patients should be advised to quit smoking due to the increased risk of progression and severity in the disease course as well as considering other negative health aspects.

Has not been published before and is not considered for publication elsewhere. Sincerely,

Linnea Hartman, Bachelor of medicine Örebro University

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Multipel skleros (MS) är en sjukdom i centrala nervsystemet, hjärna och ryggmärg, som primärt drabbar unga vuxna. Symtomen kommer oftast i så kallade skov som uppstår på grund av inflammationer och ärr på nervtrådarna, vilket gör att nervimpulserna inte kommer fram som de ska. Ingen botande behandling finns, men läkemedel kan både lindra symtom och bromsa sjukdomsförloppet. I sjukdomens slutstadium leder bestående nervskada till ökande handikapp som påverkar patienternas livskvalitet. Risken för bestående handikapp ökar bland annat på grund av allvarlighetsgrad i tidigt sjukdomsförlopp, många skov och inflammationsområden i centrala nervsystemet.

Tidigare studier har visat att rökning snabbare leder till bestående handikapp och verkar även öka sjukdomens allvarlighetsgrad. Detta kan tyda på att rökning ökar den inflammatoriska aktiviteten. Rökstopp är gynnsamt och kan minska risken för sjukdomsförsämring och bestående handikapp.

För att undersöka om det finns en association mellan rökning och inflammatorisk aktivitet utfördes en studie vid Centralsjukhuset i Karlstad genom journaldatainsamling från 53 patienter med MS. Inflammation mättes hos patienterna på flera sätt, bland annat mättes antalet skov och inflammationsområden, som upptäckts via magnetkameraundersökning av centrala nervsystemet. Patienterna grupperades som rökare eller icke-rökare och undersöktes på gruppnivå. Ingen stark association hittades mellan grupperna avseende inflammatorisk aktivitet. Rökare hade en något större mängd aktiva inflammationsområden på magnetkameraundersökning än icke-rökare. Resultaten kan dock bero på ett för litet patientmaterial. Fortsatt forskning behövs inom området.

Då andra studier visat att rökning är negativt för sjukdomen, samt ur andra hälsoaspekter, bör rökande patienter med MS uppmanas till rökstopp och få tillgång till rökavvänjning.

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The study data was obtained under a protocol approved by the Head Manager of the Neurological Department at Karlstad Central hospital. Patients were not asked for consents nor informed about the study. Reviews of medical records consist of intimate and private information and require high standards concerning patients’ integrity and privacy. All patient data was de-identified and managed only by individuals associated with the study. Considering the small patient selection and many parameters investigated, results were presented on group level to limit patient recognition.

MS is a chronic disease and in the end stages progressive, accounting for neurological disability, limiting motor-, sensory- and autonomic function as well as affecting cognitive and psychologic function, leading to reduced quality of life and working capacity. It is important to treat in early course and limit every modifiable risk factor possible in consideration of patients’ best interest and to provide the appropriate care and disease control. Accordingly, patient and neurologist should discuss the possibilities of reducing such risk factors, smoking included.

The method of retrospective data collection provides information about everyday routines and the adherence to guidelines as well as to potentially identify systematic errors to amend everyday practice, hopefully resulting in approved patient care.

Patients have not been discriminated in received healthcare or treatment selection due to this study’s design and implementation since all data is gathered retrospectively.

There might still be several unknown factors influencing disease progression and inflammatory burden in MS, therefore, research is of importance in this area.