Vitamin D levels not associated with adverse outcomes in European MS patients

WEST PALM BEACH, Florida — Genetically predicted levels of 25-hydroxyvitamin D were generally not associated with adverse disease outcomes in MS patients of European ancestry, according to a study presented at ACTRIMS Forum.

“There’s been an ongoing debate in the scientific world about the effects of vitamin D on disease prognosis,” Eleni Vasileiou, postdoctoral researcher in neuroimmunology at Johns Hopkins Hospital, said in the presentation. “There have been studies that reported a protective effect of vitamin D supplementation, but this could not be validated from bigger clinical trials.”

Vasileiou and colleagues sought to characterize the association of genetically determined 25(OH)D levels and disease outcomes in MS, since previous observational studies suggest that low levels may be linked with increased disease progression and negative long-term effects.
They included nearly 2,000 participants of European ancestry with MS with available genotyping data from cohorts from the CombiRx trial, Johns Hopkins MS Center and the Winnipeg IMID study. Outcomes across all cohorts included Expanded Disability Status Scale; walking speed; nine-hole peg test; new lesions; whole brain, gray, and white matter volume; and optical coherence tomography-derived ganglion cell inner plexiform layer thickness.

Using statistics from a large genome-wide association study of 25(OH)D levels that included 417,580 individuals of European ancestry, researchers formulated polygenic scores (PGS) as linear combinations of significantly associated variants weighted by their effect on 25(OH)D levels. In addition, a multivariable model specific to the outcome of interest in each cohort was made with adjustments for genetic ancestry, age, sex, vitamin D supplementation and pooled results.

Results showed that 25(OH)D PGS was not associated with disability progression (HR = 1.06; 95% CI, 0.88-1.26), relapse rate (HR = 0.97; 95% CI, 0.87-1.10), rate of change in walking speed (0.08%; 95% CI, –0.29%-0.45%) or 9-hole peg test completion speed (0.13%; 95% CI, –0.11%-0.37%). PGS also was not linked with new lesion accrual, lesion volume or other imaging-based outcomes.

“Because those (study) participants are being treated with high doses of vitamin D — levels which can be toxic — making this observation could perhaps make us redirect our research and our efforts into something different,” Vasileiou said.