Vitamin D supplementation differentially affects seasonal multiple sclerosis disease activity

Area of Science:

• Neurology
• Endocrinology
• Immunology

Background:

• Low ultraviolet-B (UVB) radiation leads to hypovitaminosis D, a known risk factor for multiple sclerosis (MS).
• Hypovitaminosis D is associated with increased MS disease activity.

Purpose of the Study:

• To determine if vitamin D supplementation is most effective in reducing MS disease activity during periods of low UVB radiation.
• To investigate the impact of vitamin D on seasonal variations in MS disease activity.

Main Methods:

• Retrospective analysis of medical records from 40 MS patients.
• Measurement of serum 25-hydroxyvitamin D3 (25(OH)D3) concentrations via immunoassay.
• Collection of local UVB radiation data and calculation of annualized and quarterly relapse rates before and during vitamin D supplementation.

Main Results:

• Vitamin D supplementation (mean 18,950 IU/week) increased serum 25(OH)D3 by 51 nmol/L, eliminating seasonal variability.
• The annualized relapse rate in MS patients decreased by approximately 50% during supplementation.
• A significant reduction in quarterly relapse rates was observed in late winter/early spring, coinciding with the lowest 25(OH)D3 levels in unsupplemented patients.

Conclusions:

• Vitamin D supplementation effectively modulates seasonal MS disease activity.
• Supplementing MS patients with vitamin D, especially during winter and spring, demonstrates a beneficial effect on reducing disease relapses.