Amirreza Azimi, - MS Research Center, Neuroscience Institute, Tehran University of Medical Sciences,Tehran, Iran.
Sara Hanaei, - Research Center for Immunodeficiencies (RCID), Tehran University of Medical Sciences (TUMS), Tehran, Iran/Universal Scientific Education and Research Network (USERN), Tehran, Iran
Mehdi Mohammadifar, - Department of Radiology, Zanjan university of medical sciences
Sreeram V Ramagopalan, - Bristol-Myers Squibb, Uxbridge, United Kingdom
Mahsa Ghajarzadeh, - Universal Council of Epidemiology (UCE), Universal Scientific Education and Research Network (USERN), Tehran University of Medical Sciences, Tehran, Iran
Mahsa Ghajarzadeh, - Universal Council of Epidemiology (UCE), Universal Scientific Education and Research Network (USERN), Tehran University of Medical Sciences, Tehran, Iran

Background: Multiple sclerosis is an inflammatory disease while there are controversies regarding the role of vitamin D supplements in controlling relapse and disability improvement during treatment.Objective: The goal of this systematic review and meta-analysis was to evaluate the effect of vitamin D supplements on MS related relapse and Expanded Disability Status Scale (EDSS) Methods: We searched databases to include randomized clinical trials (RCTs) which were published up to October 2018. We included RCTs, being single-blinded or double-blinded or open-label trials in which one of the main outcomes was EDSS and/ or relapse after vitamin D supplementation. All statistical analyses were performed using RevMan 5.3. Odds ratios (OR) and95% confidence intervals (95% CI) were calculated for relapse between treatment arms..Mean difference was calculated for EDSS comparisons.Results: Nine articles were included for analysis.Of these 9 studies, five compared vitamin D supplement groups with placebo (group 1 studies) and 4 compared high and low dose vitamin D groups. There was a total of 561 patients analyzed. Being treated with vitamin D instead of placebo showed no effect on relapse rate(OR=0.66, 95% CI=0.28-1.54) as well as EDSS (mean difference=0.06, 95%CI (-0.31, 0.42)). The results of studies comparing high vs. low vitamin D interventions showed no significant effect on relapse rate (OR=1.08, 95%CI(0.29-4.08) as well as final EDSS (mean difference=0.17, 95%CI= -0.73, 1.07)..Conclusion: Our findings show that vitamin D supplements (high or low dose) have no significant effect on relapse rate and disability during treatment in MS patients.

Systematic review, Vitamin D, Multiple sclerosis, relapse, disability