Vitamin D in clinically isolated syndrome: evidence for possible neuroprotection

Background and purpose Vitamin D status has been associated with inflammatory activity in multiple sclerosis ( MS ), but it is not known if it is associated with gray matter volume, the loss of which predicts long‐term disability in MS . The association of vitamin D levels with brain volume measures and inflammatory activity in patients with clinically isolated syndrome ( CIS ) was investigated. Methods In the phase 2 CIS trial of atorvastatin, 25‐hydroxyvitamin D levels were evaluated for their age‐adjusted associations with normalized gray matter and brain parenchymal volumes on brain magnetic resonance imaging ( MRI ). The relationships between 25‐hydroxyvitamin D levels and clinical and MRI measures of inflammatory activity were also assessed. Results In 65 patients in this substudy, each 25 nmol/l higher 25‐hydroxyvitamin D level was associated with 7.8 ml higher gray matter volume (95% confidence interval 1.0, 14.6, P = 0.025). There was a tendency for an inverse association of average 25‐hydroxyvitamin D levels and the composite end‐point of ≥3 new brain T2 lesions or ≥1 relapse within a year (odds ratio per 25 nmol/l higher 25‐hydroxyvitamin D level 0.66, 95% confidence interval 0.41, 1.08, P = 0.096). Conclusions Vitamin D status may impact neurodegeneration after CIS , although these results should be replicated in a second study. If confirmed in clinical trials, vitamin D supplementation may reduce long‐term disability.