SAN DIEGO—Vitamin D levels may be associated with brain imaging measures in patients with progressive multiple sclerosis (MS), according to an analysis presented at the ACTRIMS 2018 Forum. The association appears to be similar in primary progressive MS and secondary progressive MS and may reflect vitamin D’s protective effect on myelin in gray matter.
Research has identified vitamin D deficiency as a risk factor for MS. Low levels of the vitamin are associated with increased risk of brain lesions, relapses, and early progression of disability. Much of the literature focuses on relapsing-remitting MS. Less is known about the part that vitamin D plays in progressive MS, particularly with respect to clinical and imaging findings.
An Analysis of Phase II Data
Justin Abbatemarco, MD, a neurologist at Cleveland Clinic, and colleagues studied results from the phase II clinical trial of ibudilast to examine the association between vitamin D levels and clinical and MRI features in progressive MS. In the trial, investigators measured participants’ serum 25 OH vitamin D levels. At baseline, they collected demographic information such as age, gender, race, disease duration, duration of progression, prior treatment history, Expanded Disability Status Scale score, MS Functional Composite, and neurocognitive testing. Baseline MRI information included brain parenchymal fraction, diffusion tensor imaging (DTI), and magnetization transfer ratio (MTR).
Dr. Abbatemarco and colleagues used Spearman correlation to evaluate the associations between total vitamin D and vitamin D3 levels and clinical or imaging characteristics. They created a linear regression model to predict clinical and imaging outcome variables.
Vitamin D Was Associated With Whole Brain MTR
The analysis included 267 patients (47.2% male) with a mean age of 55.6. In all, 137 participants had primary progressive MS, and 130 participants had secondary progressive MS. Mean disease duration was 16.4 years. The population’s mean vitamin D3 level was 40.7 ng/mL, and mean total vitamin D level was 43.8 ng/mL. Mean brain parenchymal fraction was 0.8, mean T2 lesion volume was 10.3 mL, and mean whole brain MTR was 0.1.
The investigators did not observe a significant difference in mean vitamin D levels between patients with secondary progressive MS (44.7 ng/mL) and those with primary progressive MS (42.9 ng/mL). They did find positive associations between vitamin D3 and whole brain MTR, normal appearing brain tissue MTR, and normal appearing gray matter MTR. Dr. Abbatemarco’s group found no significant associations between vitamin D levels and brain parenchymal fraction, T1 or T2 lesion volume, or DTI metrics. The associations between vitamin D3 and MRI features were similar in patients with primary progressive MS and those with secondary progressive MS.
In a multivariate analysis that controlled for age, gender, disease duration, the time that vitamin D level was obtained, and latitude of study site, associations between vitamin D3 level and whole brain MTR remained significant. Every 10-ng/mL increase in vitamin D3 was associated with a 2.1% unit increase in whole brain MTR. The investigators found no association between vitamin D3 and brain parenchymal fraction, T2 lesion volume, T1 lesion volume, and clinical scores.
Dr. Abbatemarco and colleagues plan to test the effect of longitudinal changes on clinical and MRI measures once data become available.
Smolders J, Menheere P, Kessels A, et al. Association of vitamin D metabolite levels with relapse rate and disability in multiple sclerosis. Mult Scler. 2008;14(9):1220-1224.