A systematic review of the effects of modifiable risk factor interventions on the progression of multiple sclerosis

Several risk factors are associated with multiple sclerosis (MS) progression and may be amenable to intervention.

To systematically review the evidence for interventions targeting risk factors for MS progression.

We searched six databases and existing reviews till March 2015 and consulted with experts to identify randomized controlled trials (RCTs) of interventions targeting MS risk factors (PROSPERO 2015:CRD42015016461).

In total, 37 RCTs met inclusion criteria. Expanded Disability Status Scale (EDSS) scores after exercise interventions did not differ compared with untreated controls (standardized mean differences (SMDs): 0.02; confidence interval (CI): -0.40, 0.44; I²: 0%; seven RCTs; very low quality of evidence (QoE)). Dietary interventions did not show a statistically significant effect on the relative risk (RR) of progression (RR: 0.86; CI: 0.67, 1.05; I²: 0%; four RCTs; moderate QoE) compared to placebo. EDSS scores after vitamin D supplementation were not significantly different from placebo (SMD: -0.15; CI: -0.33, 0.02; I²: 0%; five RCTs; very low QoE).

We did not identify any risk factor interventions with significant effects on MS progression, but the overall QoE was limited. More adequately powered trials are needed on vitamin D supplementation, long-term exercise, and smoking cessation.