NASHVILLE—Moderate-to-vigorous physical activity is positively associated with retinal nerve fiber layer thickness in children with multiple sclerosis (MS), according to research presented at the 2018 CMSC Annual Meeting. This finding may help to support an intervention targeting moderate-to-vigorous physical activity to improve anterior visual pathway integrity in children with MS.
More than one-third of pediatric patients with MS experience optic neuritis, and most experience visual pathway abnormalities, including reductions in their retinal nerve fiber layer and ganglion cell inner-plexiform layer. Previous studies in adults have shown a positive association between moderate-to-vigorous physical activity and the retinal nerve fiber layer; however, this association has not been evaluated in pediatric patients with MS.
To investigate the associations between mild-to-vigorous physical activity, the retinal nerve fiber layer, and the ganglion cell inner-plexiform layer in pediatric patients with MS, Alexander L. Pearson, a medical student at the University of Ottawa, and colleagues conducted a cross-sectional study.
The researchers recruited participants from the Pediatric MS and Demyelinating Disorders Center at the Hospital for Sick Children in Toronto. Eligible participants had a diagnosis of MS (according to the International Pediatric Multiple Sclerosis Study Group consensus definitions) and were younger than 18. Patients with neuroinflammatory abnormalities associated with underlying systemic or neurologic disorders, recurrent neuroinflammatory disorders other than MS, coexisting ocular pathologies, visual acuity ±6 diopters or worse, were excluded.
Participants received standardized visual evaluations, including ocular coherence tomography. Investigators performed evaluations more than 90 days after an optic neuritis episode using a spectral-domain ocular coherence tomography Cirrus scanner. Participants also completed the Godin Leisure-Time Exercise Questionnaire (GLTEQ) more than 30 days after a relapse. This questionnaire was used to calculate the health contribution score.
Generalized linear models were used to assess the associations between moderate-to-vigorous physical activity, the retinal nerve fiber layer, and the ganglion cell inner-plexiform layer when controlling for sex, number of optic neuritis episodes, disease duration at time of ocular coherence tomography, and within-subject correlation between eyes. Bonferroni correction was used to adjust for multiple comparisons.
Thirty patients participated in this study; 23 were female. Ocular coherence tomography was performed at a mean age of 15.7 (range, 10.6-18.0) and a median of 1.9 (interquartile range [IQR], 2.6) years from disease onset. The median retinal nerve fiber layer was 90 (IQR, 26.3) μm, and the median ganglion cell inner-plexiform layer was 73.5 (IQR, 20.3) μm. The median moderate-to-vigorous physical activity was 26.5 (IQR, 47) metabolic equivalents per week.
The research team found that moderate-to-vigorous physical activity was positively associated with retinal nerve fiber layer thickness. Although the retinal nerve fiber layer and ganglion cell inner-plexiform layer were moderately correlated, moderate-to-vigorous physical activity was not associated with the ganglion cell inner-plexiform layer said the authors.
“Next steps include a trial using mild-to-vigorous physical activity to improve anterior visual pathway integrity in children with MS,” the researchers concluded.