DALLAS—Early exposure to other young children may be a protective factor against the development of neuromyelitis optica, suggesting that viral infections may contribute to disease risk modification, researchers reported at the 2014 Cooperative Meeting of CMSC and ACTRIMS.
Jennifer Graves, MD, PhD, Assistant Professor of Neurology at the University of California, San Francisco, Pediatric MS Center, and colleagues sought to determine whether environmental factors known to modify the risk for multiple sclerosis (MS) were associated with the risk for neuromyelitis optica in children. The researchers used chemoluminescence assay to measure serum 25(OH) vitamin D levels, and Epstein-Barr virus, cytomegalovirus, herpes simplex virus-1, and herpes simplex virus-2 antibody responses were determined by ELISA. The investigators also used multivariate logistic regression models to determine risk factor associations with neuromyelitis optica, including adjustments for age at sampling, sex, race, and ethnicity.
Analysis was based on 36 children with neuromyelitis optica, 491 with MS, and 224 healthy controls. Dr. Graves and colleagues found that daycare (odds ratio [OR], 0.33) and breastfeeding (OR, 0.41) were associated with lower odds of having neuromyelitis optica, compared with healthy children. “C-section tended to be associated with a twofold higher odds of neuromyelitis optica,” stated Dr. Graves. “Parental smoking was not meaningfully associated with neuromyelitis optica risk.”
A total of 34 children with neuromyelitis optica, 189 with MS, and 94 controls had serotyping. The investigators found that Epstein-Barr virus exposure “tended to be associated” with lower odds of having neuromyelitis optica, compared with children with MS. Exposure to herpes simplex virus-1 and being DRB1*15-positive were also associated with lower odds of having neuromyelitis optica.
“Unlike MS, pediatric neuromyelitis optica does not appear to be associated with exposures to common herpes viruses,” the investigators concluded.
—Colby Stong