Aaen, Gregory

AbstractBackgroundWe previously identified air quality as a risk factor of interest for pediatric multiple sclerosis. The purpose of this study is to more closely examine the association between the six criteria air pollutants and pediatric MS as well as identify specific areas of toxic release using data from the Toxic Release Inventory.MethodsPediatric MS cases (N = 290) and healthy controls (N = 442) were included as part of an ongoing case–control study. We used the National Emissions Inventory system to estimate particulate exposure by county of residence for each participant. Proximity to Toxic Release Inventory (TRI) sites was also assessed using ArcGIS mapping tools. Risk‐Screening Environmental Indicators (RSEI) classified counties at risk to exposure of environmental toxic releases.ResultsFine particulate matter (PM2.5), carbon monoxide (CO), sulfur dioxide (SO2), and lead air emissions were associated with increased odds for pediatric MS (P < 0.01) for those residing within 20 miles of an MS center. Most study participants (75%) resided within 5 miles of at least one TRI site; however, the mean total pounds of stack air releases was higher for sites near MS cases (81,000 tons) compared to those near healthy controls (35,000 tons, P = 0.002). Average RSEI scores did not differ significantly between cases and controls.ConclusionOut of several air pollutants examined, we show that fine particulate matter and three other criteria pollutants (SO2, CO, and lead) were statistically associated with higher odds for pediatric MS.

AbstractObjectiveWhile prior Epstein–Barr virus (EBV) infection has been consistently associated with subsequent risk of developing multiple sclerosis (MS), the association with other common herpesviruses has been more controversial. Our objectives were to determine whether remote infection with EBV and other common herpesviruses affect the susceptibility to pediatric MS and if there are interactions between genetic and demographic factors and viral infections.MethodsCases with pediatric‐onset MS or clinically isolated syndrome within 4 years of disease onset, and controls were recruited from 16 American pediatric MS centers. Logistic regression models adjusted for potential confounders assessed the association between case status and serological evidence for past infection with EBV, cytomegalovirus (CMV), Herpes Simplex viruses‐1 (HSV‐1) and ‐2. We determined the heterogeneity of the effect of viral infection on the risk of having MS according to race, ethnicity and HLA‐DRB1:1501 status.ResultsA total of 356 pediatric cases and 493 controls were recruited. In multivariable models, EBV‐viral capsid antigen (VCA) seropositivity was associated with increased odds of having MS by 7.4 times (95% CI: 4.5–12.0, P < 0.001). Seropositivity for HSV‐1 was also associated with increased odds of having MS (OR 1.54, 95% CI: 1.06–2.25, P = 0.025) but this increase was seen only in Whites (OR = 2.18, 95% CI 1.35–3.52, P < 0.001) and those negative for HLA‐DRB1*1501 (OR = 1.89, 95% CI 1.17–3.03, P = 0.009). The effect of remote EBV infection on the risk of pediatric MS depended on race and HLA‐DRB1*15:01 status.InterpretationEBV seropositivity is strongly associated with pediatric MS, as is HSV‐1 seropositivity in subjects negative for HLA‐DRB1*15:01. Our report of interactions between select viral exposures, and age, race and DRB1 status suggests a complex effect of environmental and genetic risk factors on MS development.

Background: Strong evidence supports the role of both genetic and environmental factors in pediatric-onset multiple sclerosis (POMS) etiology. Objective: We comprehensively investigated the association between established major histocompatibility complex (MHC) and non-MHC adult multiple sclerosis (MS)-associated variants and susceptibility to POMS. Methods: Cases with onset <18 years ( n = 569) and controls ( n = 16,251) were included from the United States and Sweden. Adjusted logistic regression and meta-analyses were performed for individual risk variants and a weighted genetic risk score (wGRS) for non-MHC variants. Results were compared to adult MS cases ( n = 7588). Results: HLA–DRB1*15:01 was strongly associated with POMS (odds ratio (OR) meta = 2.95, p < 2.0 × 10 −16 ). Furthermore, 28 of 104 non-MHC variants studied (23%) were associated ( p < 0.05); POMS cases carried, on average, a higher burden of these 28 variants compared to adults (OR avg = 1.24 vs 1.13, respectively), though the difference was not significant. The wGRS was strongly associated with POMS (OR meta = 2.77, 95% confidence interval: 2.33, 3.32, p < 2.0 × 10 −16 ) and higher, on average, when compared to adult cases. Additional class III risk variants in the MHC region associated with POMS were revealed after accounting for HLA–DRB1*15:01 and HLA–A*02. Conclusion: Pediatric and adult MS share many genetic variants suggesting similar biological processes are present. MHC variants beyond HLA–DRB1*15:01 and HLA–A*02 are also associated with POMS.

Background: The role of diet in multiple sclerosis (MS) is largely uncharacterized, particularly as it pertains to pediatric-onset disease. Objective: To determine the association between dietary factors and MS in children. Methods: Pediatric MS patients and controls were recruited from 16 US centers (MS or clinically isolated syndrome onset before age 18, <4 years from symptom onset and at least 2 silent lesions on magnetic resonance imaging). The validated Block Kids Food Screener questionnaire was administered 2011–2016. Chi-squared test compared categorical variables, Kruskal–Wallis test compared continuous variables, and multivariable logistic regression analysis was performed. Results: In total, 312 cases and 456 controls were included (mean ages 15.1 and 14.4 years). In unadjusted analyses, there was no difference in intake of fats, proteins, carbohydrates, sugars, fruits, or vegetables. Dietary iron was lower in cases ( p = 0.04), and cases were more likely to consume below recommended guidelines of iron (77.2% of cases vs 62.9% of controls, p < 0.001). In multivariable analysis, iron consumption below recommended guidelines was associated with MS (odds ratio = 1.80, p < 0.01). Conclusion: Pediatric MS cases may be less likely to consume sufficient iron compared to controls, and this warrants broader study to characterize a temporal relationship. No other significant difference in intake of most dietary factors was found.

AbstractObjectiveThe aim of this study was to examine the relative contributions of body mass index (BMI) and pubertal measures for risk and age of onset of pediatric MS.MethodsCase–control study of 254 (63% female) MS cases (onset<18 years of age) and 420 (49% female) controls conducted at 14 U.S. Pediatric MS Centers. Sex‐ and age‐stratified BMI percentiles were calculated using CDC growth charts from height and weight measured at enrollment for controls, and within 1 year of onset for MS cases. Sex‐stratified associations between MS risk and age at symptom onset with both BMI and pubertal factors were estimated controlling for race and ethnicity.ResultsOnly 11% of girls and 15% of boys were prepubertal (Tanner stage I) at MS onset. 80% of girls had onset of MS after menarche. BMI percentiles were higher in MS cases versus controls (girls: P < 0.001; boys: P = 0.018). BMI was associated with odds of MS in multivariate models in postpubertal girls (OR = 1.60, 95% confidence interval [CI]: 1.12, 2.27, P = 0.009) and boys (OR = 1.43, 95% CI: 1.08, 1.88, P = 0.011). In girls with MS onset after menarche, higher BMI was associated with younger age at first symptoms (P = 0.031). Younger menarche was associated with stronger effects of BMI through mediation and interaction analysis. In pubertal/postpubertal boys, 89% of whom were obese/overweight, earlier sexual maturity was associated with earlier onset of MS (P < 0.001).InterpretationHigher BMI in early adolescence is a risk factor for MS in girls and boys. Earlier age at sexual maturity contributes to earlier age at MS onset, particularly in association with obesity.

OBJECTIVES: To describe the demographic and clinical characteristics of pediatric multiple sclerosis (MS) in the United States. METHODS: This prospective observational study included children and adolescents with MS. Cases were evaluated across 9 geographically diverse sites as part of the US Network of Pediatric MS Centers. RESULTS: A total of 490 children and adolescents (324 girls, 166 boys) were enrolled; 28% developed symptoms before 12 years of age. The proportion of girls increased with age from 58% (&lt;12 years) to 70% (≥12 years). Race and ethnicity as self-identified were: white, 67%; African American, 21%; and non-Hispanic, 70%. Most (94%) of the cases were born in the United States, and 39% had 1 or both foreign-born parents. Fifty-five percent of cases had a monofocal presentation; 31% had a prodrome (most frequently infectious), most often among those aged &lt;12 years (P &lt; .001). Children aged &lt;12 years presented more commonly with encephalopathy and coordination problems (P &lt; .001). Sensory symptoms were more frequently reported by older children (ie, those aged ≥12 years) (P &lt; .001); 78% of girls had MS onset postmenarche. The initial Expanded Disability Status Scale score for the group was &lt;3.0, and the annualized relapse rate was 0.647 for the first 2 years. Interval from symptom onset to diagnosis and from diagnosis to initiation of disease-modifying therapy was longer among those &lt;12 years of age. CONCLUSIONS: Pediatric MS in the United States is characterized by racial and ethnic diversity, a high proportion of children with foreign-born parents, and differences in clinical features and timing of treatment among those &lt;12 years of age compared with older children.

Multiple sclerosis and other demyelinating diseases in the pediatric population have received an increasing level of attention by clinicians and researchers. The low incidence of these diseases in children creates a need for the involvement of multiple clinical centers in research efforts. The Network of Pediatric Multiple Sclerosis Centers was created initially in 2006 to improve the diagnosis and care of children with demyelinating diseases. In 2010, the Network shifted its focus to multicenter research while continuing to advance the care of patients. The Network has obtained support from the National Multiple Sclerosis Society, the Guthy-Jackson Charitable Foundation, and the National Institutes of Health. The Network will continue to serve as a platform for conducting impactful research in pediatric demyelinating diseases of the central nervous system. This article provides a description of the history and development, organization, mission, research priorities, current studies, and future plans of the Network.