2026 American Academy of Neurology Abstract Website

Manon Rival¹, Christophe Demattei², Lysiane Boulet³, Thibault Mura², Hanane Agherbi⁴, Thouvenot Eric¹
¹IGF, CNRS, INSERM, Univ Montpellier, Service de Neurologie, CHU Nimes, ²Laboratoire de Biostatistique, Epidémiologie clinique, Santé Publique Innovation et Méthodologie (BESPIM), Univ Montpellier, CHU Nimes, ³Laboratoire de Biochimie Hormonale et Nutritionnelle, CHU Grenoble-Alpes, ⁴Service de Neurologie, CHU Nimes

Objective:

To evaluate the impact of plasma vitamin D (VD) increase on the 24-months risk of disease activity (DA, defined as a relapse and/or MRI activity (new and/or contrast-enhancing lesions)).

Background:

D-lay MS (NCT01817166), a double-blind, placebo-controlled, 24-month, parallel trial in 314 clinically isolated syndrome (CIS) patients across France, showed that oral cholecalciferol (vitamin D3) 100,000 IU every two weeks significantly reduced DA.

Design/Methods:

VD levels were measured centrally by mass spectrometry at baseline and 3 months to reflect the overall change in VD during the study. Groups were compared using a Wilcoxon test. Spearman R correlation coefficient was used for correlations. The effect of VD on DA was analysed using ROC curves and adjusted Cox models.

Results:

266 patients were analyzed (n=140 in the VD group and n=126 in the placebo group) and showed similar median VD levels (52.0 vs. 49.3 nmol/L). In both groups, VD levels at baseline did not predict DA. VD increase at 3 months discriminated DA vs. no DA in the placebo group (median increase 1.6 nmol/L, p=0.036) but not in the VD group (median increase 94.1 nmol/L, p=0.602), where it weakly correlated to patients’ weight (R=-0.22, p=0.031) and to body mass index (BMI, R=-0.37, p<0.001). Combining both groups, VD increase significantly reduced the risk of DA (HR=0.58 for 100 nmol/L increase, p=0.008).

Conclusions:

In line with the global results of D-lay MS, VD increase after supplementation with 100,000 IU cholecalciferol every two weeks significantly reduced the risk of DA at the cohort level. Interestingly, variations of VD levels at 3 months were predictive of DA in the placebo group but not in the VD group, suggesting a maximal effect in this high dosage. Overall, given the excellent safety of VD, these findings suggest that individual adjustment of this high-dose supplementation regimen may be unnecessary.