The Link Between Vitamin D and Multiple Sclerosis: Implications for Relapse Management

Data from the Czech national multiple sclerosis registry show that higher vitamin D status is associated with lower relapse risk and reduced MRI inflammatory activity in adults with MS during long-term follow-up.

Unlike smaller randomized trials and fixed-dose interventions that yielded mixed results, this large, real-world cohort offers extended follow-up with repeated biochemical measurements, providing clearer context for observed links between serum vitamin D and clinical events in routine practice.

In a 10-year analysis of 1,861 adults drawn from the registry, each 10 nmol/L increase in 25-hydroxyvitamin D was associated with a 6.7% decrease in relapse risk (p<0.001). Patients with mean concentrations above 100 nmol/L had fewer relapses and a lower proportion of new or enlarging T2 lesions on MRI compared with those below 75 nmol/L, indicating concordant effects on clinical and radiological endpoints.

No significant adverse effects were observed with higher 25(OH)D levels; dosing in the cohort reflected individually adjusted supplementation as part of routine care rather than a fixed protocol.