Gut microbiome and physical activity in paediatric-onset multiple sclerosis
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Updated: Nov 2, 2026

Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing
Published on: October 15, 2019
S Stephens1, T Da Silva1, F Zhu2
1The Hospital for Sick Children, University of Toronto, Canada.
Objectives:
To examine associations between physical activity (PA) and gut microbiome diversity and composition in youth with pediatric onset multiple sclerosis (POMS) versus monophasic demyelinating syndromes (mono-ADS) and unaffected controls (UC), and to compare active versus inactive POMS.
Methods:
Thirty-seven youth with POMS, 40 mono-ADS, and 36 UC from the Canadian Pediatric Demyelinating Disorders Study were included. Stool samples underwent 16S rRNA sequencing. PA was assessed using the Godin Leisure-Time Exercise Questionnaire and analyzed as continuous (total PA, moderate and vigorous PA, strenuous PA) and binary (active vs. inactive) variables. Alpha diversity (Shannon, Simpson, Chao1) and beta diversity (UniFrac, Bray-Curtis) were assessed using permutation-based linear regression and PERMANOVA, adjusting for age, sex, and BMI. LEfSe identified differentially abundant taxa, and Spearman correlations assessed associations with PA.
Results:
No differences in alpha diversity were observed. In POMS, total PA showed modest associations with UniFrac beta diversity (R²≈0.04-0.05, p≈0.08; FDR p=0.13), but not Bray-Curtis. Inactive POMS had lower Firmicutes and higher Bacteroidetes, with enrichment of Bifidobacterium, Escherichia-Shigella, and Lactobacillus, whereas active POMS showed higher Firmicutes (e.g., Roseburia, Lachnospiraceae); Bifidobacterium was ∼4-fold higher in inactive POMS. These patterns were not observed in controls or mono-ADS. Firmicutes positively correlated with PA intensity, while Actinobacteria, Bacteroidetes, and Bifidobacterium were inversely correlated INTERPRETATION: PA-microbiome associations appear unique in POMS demonstrated by specific compositional patterns. These findings should be confirmed in larger cohorts with objective measures of physical activity and more comprehensive assessment of potential confounding factors.
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