Association Between Alcohol Consumption and Disability Accumulation in Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Previous studies have indicated that alcohol consumption is associated with multiple sclerosis (MS) disease progression. We aimed to study the influence of alcohol consumption habits on disease progression and health-related quality of life in MS. METHODS: We categorized patients from 2 population-based case-control studies by alcohol consumption habits at diagnosis and followed them up to 15 years after diagnosis through the Swedish MS registry regarding changes in the Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Impact Scale 29 (MSIS-29). We used Cox regression models with 95% confidence intervals (CIs) using 24-week confirmed disability worsening, EDSS 3, EDSS 4, and physical and psychological worsening from the patient's perspective as end points. RESULTS: Our study comprised 9,051 patients with MS, with a mean age of 37.5 years at baseline/diagnosis. Compared with nondrinking, low and moderate alcohol consumption was associated with reduced risk of EDSS-related unfavorable outcomes (hazard ratios between 0.81 and 0.90) and with reduced risk of physical worsening. The inverse association was confined to relapsing-remitting MS and was more pronounced among women. High alcohol consumption did not significantly affect disease progression. The inverse relationship between low-moderate alcohol consumption and disability progression became stronger when we only included those who had not changed their alcohol consumption during follow-up (hazard ratios between 0.63 and 0.71). There were no differences in measures of disability at baseline between drinkers who continued drinking alcohol after diagnosis and those who later discontinued. Our findings speak against bias due to reverse causation. DISCUSSION: Low and moderate alcohol consumption was associated with more favorable outcomes in relapsing-remitting MS, compared with nondrinking, while there was no significant influence of high alcohol consumption on disease outcomes.

Adolescent sleep patterns, genetic predisposition, and risk of multiple sclerosis.

STUDY OBJECTIVES: Shift work, insufficient sleep, and poor sleep quality at young age have been associated with increased risk of multiple sclerosis (MS). This study aimed to investigate the potential interaction between aspects of inadequate sleep (short sleep, phase shift, and poor sleep quality) during adolescence and HLA-DRB1*15:01 in relation to MS risk. METHODS: We used a Swedish population-based case-control study (1253 cases and 1766 controls). Subjects with different sleep patterns during adolescence and HLA-DRB1*15:01 status were compared regarding MS risk by calculating odds ratios (OR) with 95% confidence intervals (CI) using logistic regression models. Additive interaction between aspects of inadequate sleep and HLA-DRB1*15:01 status was assessed by calculating the attributable proportion due to interaction (AP) with 95% CI. RESULTS: Short sleep duration (<7 hours/night) during adolescence acted synergistically with HLA-DRB1*15:01, increasing the risk of MS (AP 0.38, 95% CI 0.01-0.75, p=0.04). Similarly, subjective low sleep quality during adolescence interacted with HLA-DRB1*15:01 regarding risk of MS (AP 0.30, 95% CI 0.06-0.56, p=0.03), whereas phase shift did not significantly influence the risk of the disease, irrespective of HLA-DRB1*15:01 status. CONCLUSIONS: Our findings underscore the importance of addressing inadequate sleep during adolescence, particularly in the context of the HLA-DRB1*15:01 allele, as it appears to amplify the risk of subsequently developing MS.

Genetics of immune response to Epstein-Barr virus: prospects for multiple sclerosis pathogenesis.

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

Association between sun exposure habits and disease progression in multiple sclerosis.

BACKGROUND AND PURPOSE: Higher latitude has been associated with increased occurrence of multiple sclerosis (MS) and with more severe disease. The aim was to study the impact of sun exposure habits on MS disease progression and health-related quality of life. METHODS: Patients from a population-based case-control study were categorized based on sun exposure habits at diagnosis and were followed up to 15 years post-diagnosis through the Swedish MS registry (n = 3314) with regard to changes in Expanded Disability Status Scale (EDSS). Linear mixed models were used to analyse long-term changes, while Cox regression models, with 95% confidence intervals, were used to investigate outcomes, including 24-week confirmed diasability worsening, EDSS3, EDSS4, and physical worsening as measured by the physical component of the Multiple Sclerosis Impact Scale 29. RESULTS: Compared to average sun exposure (median value), low exposure to sunlight was associated with faster EDSS progression, increased risk of confirmed disability worsening (hazard ratio [HR] 1.48, 95% CI 1.21-1.81), increased risk of reaching EDSS 3 (HR 1.35, 95% CI 1.02-1.79), EDSS 4 (HR 1.47, 95% CI 1.01-2.20) and self-reported physical worsening (HR 1.27, 95% CI 1.00-1.62). Significant trends revealed a lower risk of unfavourable outcomes with increasing sun exposure. CONCLUSIONS: Very low levels of sun exposure are associated with worse disease progression and health-related quality of life in patients with MS.

Medically unexplained symptoms are common in women in tertiary neurological healthcare center: A survey cohort study of persons investigated for suspected multiple sclerosis.

BACKGROUND: A significant proportion of individuals with suspicious onset of multiple sclerosis (MS) does not fulfill the diagnostic criteria. Although some receive other diagnoses, many remain undiagnosed and lack healthcare follow-up. This study aimed to characterize persons with undetermined diagnosis (PwUD) through a questionnaire. METHODS: Incident cases with suspected MS were consecutively admitted to a tertiary neurological healthcare center in a prospective cohort study. Those who remained undiagnosed after 40 months (mean, range 31-52) were considered PwUD. They completed a modified questionnaire, previously used in a population-based case-control study of incident MS cases. Their responses were compared with two control cohorts, persons with MS (PwMS) and healthy controls, randomly selected from national registries, matched by age, gender, and area of residence. RESULTS: Out of 271 patients with suspected MS onset, 72 (20.3%) were PwUD with a female majority (79%). The response rate was 83% and 39% reported persisting MS-like symptoms. Compared to controls (n = 548) and PwMS (n = 277), fewer PwUD were currently smoking (p = .4 and p = .03), consumed less alcohol (p = .04 and p = .01), and had children (p = .02 and p = .002). PwUD reported occurrence of other autoimmune disease in 29%, higher compared to PwMS and controls (p < .001 and p < .001). CONCLUSIONS: UD is common among persons investigated for suspected MS, in particular among female parents. Our data suggest that PwUD can be characterized as nonsmokers with low alcohol consumption and a higher prevalence of autoimmune disease, in particular thyroid disease.

Head trauma results in manyfold increased risk of multiple sclerosis in genetically susceptible individuals.

BACKGROUND: Large register-based studies have reported an association between head trauma and increased risk of multiple sclerosis (MS). We aimed to investigate possible interactions between head trauma and MS-associated HLA genes in relation to MS risk. METHODS: We used a Swedish population-based case-control study (2807 incident cases, 5950 matched controls with HLA genotypes available for 2057 cases, 2887 controls). Subjects with and without a history of self-reported head trauma were compared regarding MS risk, by calculating ORs with 95% CIs using logistic regression models. Additive interaction between head trauma, HLA-DRB1*1501 and absence of HLA-A*0201, was assessed by calculating the attributable proportion (AP) due to interaction. RESULTS: A history of head trauma was associated with a 30% increased risk of subsequently developing MS (OR 1.34, 95% CI 1.17 to 1.53), with a trend showing increased risk of MS with increasing number of head impacts (p=0.03). We observed synergistic effects between recent head trauma and HLA-DRB1*15:01 as well as absence of HLA*02:01 in relation to MS risk (each AP 0.40, 95% CI 0.1 to 0.7). Recent head trauma in individuals with both genetic risk factors rendered an 18-fold increased risk of MS, compared with those with neither the genetic risk factors nor a history of head trauma (OR 17.7, 95% CI 7.13 to 44.1). CONCLUSIONS: Our findings align with previous observations of a dose-dependent association between head trauma and increased risk of MS and add a novel aspect of this association by revealing synergistic effects between recent head trauma and MS-associated HLA genes.

Outborn newborns drive birth asphyxia mortality rates-An 8 year analysis at a rural level two nursery in Uganda.

Birth asphyxia is a leading cause of global neonatal mortality. Most cases occur in low- and middle- income countries and contribute to half of neonatal deaths in Uganda. Improved understanding of the risk factors associated with mortality among these patients is needed. We performed a retrospective cohort study of a clinical database and report maternal demographics, clinical characteristics and outcomes from neonates with birth asphyxia at a Ugandan level two unit from 2014 through 2021. "Inborn" patients were born at the hospital studied and "outborn" were born at another facility or home and then admitted to the hospital studied. Doctors assigned the patient's primary diagnosis at death or discharge. We performed a Poisson model regression of factors associated with mortality among patients with asphyxia. The study included 1,565 patients with birth asphyxia and the proportion who were outborn rose from 26% to 71% over eight years. Mortality in asphyxiated patients increased over the same period from 9% to 27%. Factors independently associated with increased death included outborn birth location (ARR 2.1, p<0.001), admission in the year 2020 (ARR 2.4, p<0.05) and admission respiratory rate below 30bpm (RR 3.9, p<0.001), oxygen saturation <90% (ARR 2.0, p<0.001) and blood sugar >8.3 mmol/L (RR 1.7, p<0.05). Conversely, a respiratory rate >60bpm was protective against death (ARR 0.6, p<0.05). Increased birth asphyxia mortality at this referral unit was associated with increasing admission of outborn patients. Patients born at another facility and transferred face unique challenges. Increased capacity building at lower-level birth facilities could include improved staffing, training and equipment for labor monitoring and newborn resuscitation as well as training on the timely identification of newborns with birth asphyxia and resources for transfer. These changes may reduce incidence of birth asphyxia, improve outcomes among birth asphyxia patients and help meet global targets for newborn mortality.

Prevalence and pattern of retinopathy of prematurity at two national referral hospitals in Uganda: a cross-sectional study.

BACKGROUND: Retinopathy of prematurity (ROP) is a leading cause of blindness in children and an ROP epidemic is predicted this decade in sub-Saharan Africa. With the increasing survival rate of preterm babies in Uganda, and no data on ROP prevalence, there is a need to assess the burden of ROP to inform preventive strategies and targeted screening. METHODS: We conducted a two-center cross-sectional study of preterm (< 37 weeks gestational age) infants from the neonatal units of Kawempe National Referral Hospital (KNRH) and Mulago Specialised Women and Neonatal Hospital (MSWNH) from August 2022 to October 2022. An ophthalmologist examined all participants using an indirect ophthalmoscope with a + 20D convex lens and captured digital images using a Volk iNview™ Fundus Camera. The collected data were entered into Epidata 4.2 and exported to Stata 14.0 for analysis. RESULTS: 331 preterm infants enrolled in this study. The oxygen received was unblended. The mean gestational age was 30.4 ± 2.7 weeks, and the mean birth weight was 1597 ± 509 g. 18/101 (17.8%) were found to have any ROP amongst the preterm infants recruited from MSWNH, 1/230 (0.4%) from KNRH [95% CI] had any stage of ROP (i.e. stage 5). Of these, 8 (42.1%) had stage 2 ROP. Infants with a birth weight below 1500 g were 10 times more likely to have ROP than those among infants with a birth weight more than 1500 g [AOR: 10.07 (2.71-37.44)]. Infants who were not fed exclusively on breast milk had higher odds of having ROP than those exclusively fed on breast milk [AOR: 7.82(1.92-31.82)]. CONCLUSION: 6% of preterm infants born in two tertiary hospitals in Uganda were found to have ROP. Lack of exclusive feeding on breast milk and birth weight of less than 1500 g were strong predictors of ROP. The higher prevalence of ROP in MSWNH calls for cautious use of oxygen among preterms. We recommend targeted ROP screening for those at risk.

Risk factors for multiple sclerosis in the context of Epstein-Barr virus infection.

Compelling evidence indicates that Epstein Barr virus (EBV) infection is a prerequisite for multiple sclerosis (MS). The disease may arise from a complex interplay between latent EBV infection, genetic predisposition, and various environmental and lifestyle factors that negatively affect immune control of the infection. Evidence of gene-environment interactions and epigenetic modifications triggered by environmental factors in genetically susceptible individuals supports this view. This review gives a short introduction to EBV and host immunity and discusses evidence indicating EBV as a prerequisite for MS. The role of genetic and environmental risk factors, and their interactions, in MS pathogenesis is reviewed and put in the context of EBV infection. Finally, possible preventive measures are discussed based on the findings presented.

Treatment Options for Epstein-Barr Virus-Related Disorders of the Central Nervous System.

Epstein-Barr virus (EBV), a causative agent for several types of lymphomas and mucosal cancers, is a human lymphotropic herpesvirus with the capacity to establish lifelong latent infection. More than 90% of the human population worldwide is infected. The primary infection is usually asymptomatic in childhood, whereas infectious mononucleosis (IM) is common when the infection occurs in adolescence. Primary EBV infection, with or without IM, or reactivation of latent infection in immunocompromised individuals have been associated with a wide range of neurologic conditions, such as encephalitis, meningitis, acute disseminated encephalomyelitis, and cerebellitis. EBV is also involved in malignant lymphomas in the brain. An increasing number of reports on EBV-related disorders of the central nervous system (CNS) including the convincing association with multiple sclerosis (MS) have put in focus EBV-related conditions beyond its established link to malignancies. In this review, we present the clinical manifestations of EBV-related CNS-disorders, put them in the context of known EBV biology and focus on available treatment options and future therapeutic approaches.

Inverse association between Mediterranean diet and risk of multiple sclerosis.

OBJECTIVE: There is some evidence implicating diet in the development of inflammatory diseases. We aimed to study the influence of dietary habits on the risk of developing multiple sclerosis (MS). METHODS: We used a population-based case-control study recruiting incident cases of MS (1953 cases, 3557 controls). Subjects with different dietary habits 5 years prior to MS diagnosis were compared regarding MS risk by calculating odds ratios (OR) with 95% confidence intervals (CI) using logistic regression models. Adjustment was made for a large number of environmental and lifestyle habits, including ancestry, smoking, alcohol consumption, body mass index, physical activity, and sun exposure habits. RESULTS: Mediterranean diet was associated with lower risk of developing MS (adjusted OR = 0.54, 95% CI: 0.34-0.86, p = 0.009), compared with Western-style diet. There was no significant association between vegetarian/vegan diet and MS risk (adjusted OR = 0.96, 95% CI: 0.75-1.24, p = 0.976), nor between diet with low glycemic index and MS risk (adjusted OR = 0.93, 95% CI: 0.60-1.42, p = 0.518). CONCLUSIONS: Mediterranean diet may exert a protective influence regarding the risk of subsequently developing MS compared with Western-style diet.

Feasibility and usability of a very low-cost bubble continuous positive airway pressure device including oxygen blenders in a Ugandan level two newborn unit.

BACKGROUND: Preterm birth and resulting respiratory failure is a leading cause of newborn death- the majority of which occur in resource-constrained settings and could be prevented with bubble continuous positive airway pressure (bCPAP). Commercialized devices are expensive, however, and sites commonly use improvised devices utilizing 100% oxygen which can cause blindness. To address this, PATH and a multidisciplinary team developed a very low-cost bCPAP device including fixed-ratio oxygen blenders. OBJECTIVE: We assessed feasibility of use of the device on neonatal patients as well as the usability and acceptability of the device by healthcare workers. This study did not evaluate device effectiveness. METHODS: The study took place in a Ugandan level two unit. Neonates with respiratory failure were treated with the bCPAP device. Prospective data were collected through observation as well as likert-style scales and interviews with healthcare workers. Data were analyzed using frequencies, means and standard deviation and interviews via a descriptive coding method. Retrospectively registered via ClinicalTrials.gov number NCT05462509. RESULTS: Fourteen neonates were treated with the bCPAP device in October-December 2021. Patients were born onsite (57%), with median weight of 1.3 kg (IQR 1-1.8). Median treatment length was 2.5 days (IQR 2-6). bCPAP was stopped due to: improvement (83%) and death (17%). All patients experienced episodes of saturations >95%. Median time for device set up: 15 minutes (IQR 12-18) and changing the blender: 15 seconds (IQR 12-27). After initial device use, 9 out of 9 nurses report the set-up as well as blender use was "easy" and their overall satisfaction with the device was 8.5/10 (IQR 6.5-9.5). Interview themes included the appreciation for the ability to administer less than 100% oxygen, desire to continue use of the device, and a desire for additional blenders. CONCLUSIONS: In facilities otherwise using 100% oxygen, use of the bCPAP device including oxygen blenders is feasible and acceptable to healthcare workers. TRIAL REGISTRATION: ClinicalTrials.gov, Identifier NCT05462509.

Influence of oral tobacco versus smoking on multiple sclerosis disease activity and progression.

We aimed to study the influence of smoking habits, exposure to passive smoking and snuff use on disease progression, cognitive performance and quality of life in patients with multiple sclerosis (MS). METHOD: Patients from two population-based case-control studies were categorised based on tobacco exposure at diagnosis and were followed up to 15 years post diagnosis through the Swedish MS registry (n=9089) regarding changes in Expanded Disability Status Scale (EDSS), Multiple Sclerosis Impact Scale 29 and Symbol Digit Modalities Test. We used linear mixed models to analyse long-term changes, and Cox regression models with 95% CI using 24-week confirmed disability worsening, reaching EDSS 3 and EDSS 4, respectively, physical and psychological worsening and cognitive disability worsening as end points. The influence of smoking cessation post diagnosis was also investigated. RESULTS: Compared with non-smokers, current smokers had a faster EDSS progression (ßcurrent smoking×time=0.03, 95% CI 0.02 to 0.04). A faster EDSS progression was also associated with passive smoking (ßcurrent passive smoking×time=0.04, 95% CI 0.03 to 0.06). Smoke exposure negatively impacted all secondary outcomes. Those who continued smoking had worse outcomes than those who stopped smoking post diagnosis. Snuff users had a more favourable EDSS progression, compared with never users. CONCLUSIONS: Our findings indicate that both smoking and passive smoking have a negative influence on MS and that smoking cessation post diagnosis may be an important secondary preventive measure. Snuff use was associated with slower disease progression, suggesting that nicotine replacement therapy could be an attractive way to increase the chance of quitting smoking among patients with MS.

Transmission of negative biases through social commentary included in neonatal intensive care unit progress notes.

OBJECTIVE: To determine how the perception of families elicited after reading progress note social commentary differs by patient race. STUDY DESIGN: We retrospectively performed content analysis of social commentary in physician progress notes for neonatal intensive care unit patients hospitalized from 2018-2019. Neonatologists blinded to patient race rated how commentary impacted their perception of the patient's family on a 5-point Likert scale. Frequency of negative ratings was compared across reported race using chi-squared tests. RESULTS: We reviewed charts of 460 neonates. In total, 225 (49%) contained social commentary beyond parents' names. Twelve neonatologists rated how commentaries impacted their perception of the patient's family; 79%, 18%, and 3% were rated neutrally, negatively, and positively, respectively. Frequency of negative ratings was significantly greater among American Indian/Alaska Native than other patients (35% vs. 22%, p < 0.001). CONCLUSIONS: Physician documentation of social commentary in patient notes may reflect and perpetuate implicit biases that contribute to race-based healthcare disparities.

Disease Activity and Health-Related Quality of Life Among Patients With Rheumatoid Arthritis With Different Alcohol Consumption Habits.

OBJECTIVE: Multiple studies have found a relationship between alcohol consumption and disease activity in rheumatoid arthritis (RA), although reverse causation has been suggested to explain the association. We aimed to study the relationship between alcohol consumption and disease activity, disease progression, and health-related quality of life in patients with RA. METHODS: We followed up 1,228 patients with newly diagnosed RA from a population-based case-control study, Epidemiological Investigation of Rheumatoid Arthritis (EIRA). Drinkers and non-drinkers were compared to evaluate risk of unfavorable outcomes regarding disease activity and health-related quality of life. Odds ratios with 95% confidence intervals were calculated using logistic regression models. RESULTS: Non-drinkers at baseline had higher disease activity and estimated their pain as more severe compared to drinkers. At 1 year of follow-up, non-drinkers reported higher swollen and tender joint counts and experienced more pain and fatigue, lower global health scores, and lower health-related quality of life. The inverse relationship between alcohol consumption and RA-specific outcomes was also observed when comparing drinkers and non-drinkers who had not changed their alcohol consumption habits at or after the year of disease onset. Those who stopped drinking postbaseline experienced higher disease activity, more pain, and lower health-related quality of life at 1 year of follow-up, compared to drinkers, although there was no difference in disease activity at baseline between drinkers who continued versus discontinued drinking. Our findings argue against bias due to reverse causation. CONCLUSION: Alcohol consumption was associated with lower disease activity and higher health-related quality of life in RA patients in a dose-dependent manner.

Association between exposure to combustion-related air pollution and multiple sclerosis risk.

BACKGROUND: Smoking and occupational pulmonary irritants contribute to multiple sclerosis (MS) development. We aimed to study the association between ambient air pollution and MS risk and potential interaction with the human leukocyte antigen (HLA)-DRB1*15:01 allele. METHODS: Exposure to combustion-related air pollution was estimated as outdoor levels of nitrogen oxides (NOx) at the participants' residence locations, by spatially resolved dispersion modelling for the years 1990-18. Using two population-based case-control studies (6635 cases, 8880 controls), NOx levels were associated with MS risk by calculating odds ratios (OR) with 95% confidence intervals (CI) using logistic regression models. Interaction between high NOx levels and the HLA-DRB1*15:01 allele regarding MS risk was calculated by the attributable proportion due to interaction (AP). In addition, a register study was performed comprising all MS cases in Sweden who had received their diagnosis between 1993 and 2018 (n = 22 173), with 10 controls per case randomly selected from the National Population register. RESULTS: Residential air pollution was associated with MS risk. NOx levels (3-year average) exceeding the 90th percentile (24.6 µg/m3) were associated with an OR of 1.37 (95% CI 1.10-1.76) compared with levels below the 25th percentile (5.9 µg/m3), with a trend of increasing risk of MS with increasing levels of NOx (P <0.0001). A synergistic effect was observed between high NOx levels (exceeding the lower quartile among controls) and the HLA-DRB1*15:01 allele regarding MS risk (AP 0.26, 95% CI 0.13-0.29). CONCLUSIONS: Our findings indicate that moderate levels of combustion-related ambient air pollution may play a role in MS development.

Observed associations between indicators of socioeconomic status and risk of multiple sclerosis in Sweden are explained by a few lifestyle-related factors.

BACKGROUND AND PURPOSE: The association between socioeconomic status (SES) and the risk of multiple sclerosis (MS) is unclear. The aim was to study whether a potential association between indicators of SES and MS risk in Sweden is explained by lifestyle/environmental factors. METHODS: Using the Swedish MS registry and the Swedish patient registries, a register study was performed comprising all cases diagnosed with MS in Sweden between 1990 and 2018 (N = 24,729) and five randomly selected controls per case, matched by year and age at disease onset, sex and residential area at disease onset. Data from two matched case-control studies combined comprising data on environment/lifestyle factors (7193 cases, 9609 controls, inclusion period 2005-2018) were also utilized. For all participants, information regarding ancestry, formal education (available 1990-2018) and family income (available 1998-2018) was retrieved from the National Board of Health and Welfare. RESULTS: The registry study revealed no association between education and MS risk, whereas an income exceeding the upper quartile was associated with lower MS risk compared to having an income in the lowest quartile (odds ratio 0.86, 95% confidence interval 0.82-0.90). These findings were replicated in the crude analyses of the case-control study. However, after adjustment for confounding, no association was observed between income and risk of MS. CONCLUSIONS: Education and income were not associated with occurrence of MS after adjustment for a few lifestyle-related factors (smoking, alcohol consumption, body mass index and sun exposure habits), indicating that SES has no influence on MS risk besides its association with these lifestyle factors in the Swedish context.

Insufficient sleep during adolescence and risk of multiple sclerosis: results from a Swedish case-control study.

BACKGROUND: Shift work, which often results in sleep deprivation and circadian desynchrony, has been associated with increased risk of multiple sclerosis (MS). We aimed at studying the impact of sleep duration, circadian disruption and sleep quality on MS risk. METHODS: We used a Swedish population-based case-control study (2075 cases, 3164 controls). Aspects of sleep were associated with MS risk by calculating OR with 95% CIs using logistic regression models. RESULTS: Compared with sleeping 7-9 hours/night during adolescence, short sleep (<7 hours/night) was associated with increased risk of developing MS (OR 1.4, 95% OR 1.1-1.7). Similarly, subjective low sleep quality during adolescence increased the risk of subsequently developing MS (OR 1.5, 95% CI 1.3 to 1.9), whereas phase shift did not significantly influence the risk. Our findings remained similar when those who worked shifts were excluded. CONCLUSIONS: Insufficient sleep and low sleep quality during adolescence seem to increase the risk of subsequently developing MS. Sufficient restorative sleep at young age, needed for adequate immune functioning, may be a preventive factor against MS.